spongiform encephalopathies · elizabeth mumford ernst nef lukas perler andrew speedy food and...
TRANSCRIPT
ManageMent OF transMissible spOngiFOrM encephalOpathies in livestOck Feeds and Feeding
3
Olivier Fumièredaniel guidondagmar heim
elizabeth Mumford ernst nef
lukas perlerandrew speedy
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONSrome, 2007
CApACITy BUILDING FOR SURvEILLANCE AND pREvENTION OF BSE AND OTHER ZOONOTIC DISEASES
course manual
The designations employed and the presentation of material in this information product do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal or development status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.
All rights reserved. Reproduction and dissemination of material in this information product for educational or other non-commercial purposes are authorized without any prior written permission from the copyright holders provided the source is fully acknowledged. Reproduction of material in this information product for resale or other commercial purposes is prohibited without written permission of the copyright holders. Applications for such permission should be addressed to the Chief, Electronic Policy and Support Branch, Communication Publishing Division, FAO, Viale delle Terme di Caracalla, 00153 Rome, Italy or by e-mail to [email protected]
© FAO 2007
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CONTENTS
Foreword v
Courseobjectives vii
INTRODUCTION TO TRANSmISSIBLE SpONGIFORm ENCEpHALOpATHIES
1. transmissible spongiform encephalopathies 1
2. bovine spongiform encephalopathy 3
3. Measures for control and prevention 5
4. clinical signs of bse 10
5. diagnosis of bse 10
6. surveillance systems 14
7. risk assessment 16
8. references 17
OvERvIEw: ImpLEmENTATION OF TRANSmISSIBLE SpONGIFORm ENCEpHALOpATHIES mEASURES FOR LIvESTOCk FEEDS
1. general concepts 21
2. ban on srM in feeds 21
3. scope of feed bans 22
4. control of cross contamination 22
5. import restrictions 23
6. enforcement 23
7. references 23
pROTEIN USE IN LIvESTOCk FEEDING
1. general concepts 25
2. protein sources and supplements 28
3. summary of tse-relevant concepts 31
4. references 32
INACTIvATION OF TRANSmISSIBLE SpONGIFORm ENCEpHALOpATHIES AGENTS
1. general concepts 33
2. inactivation procedures 33
3. Future development of inactivation in rendering 35
4. references 36
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RENDERING OF ANImAL By-pRODUCTS
1. general concepts 37
2. the rendering process 37
3. goals of the rendering process 38
4. Other options for animal by-product disposal 39
5. animal by-product legislation in the european Union 39
6. the future use of meat and bone meal 41
7. summary of tse-relevant concepts 41
8. references 42
mANUFACTURING OF COmpOUND FEEDS FOR LIvESTOCk
1. general concepts 43
2. structure of a feed production plant 43
3. Feed production processes 45
4. references 50
LIvESTOCk FEED REGULATIONS AND INDUSTRy GUIDELINES
1. general concepts 51
2. international standards and national/regional regulations 52
3. implementation of international and national standards and regulations: industry guidelines 57
4. summary of tse-relevant concepts 60
5. references 61
QUALITy ASSURANCE IN FEED-pRODUCING pLANTS
1. general concepts 63
2. important points for quality assurance 64
3. documentation and data 69
4. complaints and product recall 70
5. sample collection 71
6. summary of tse-relevant concepts 72
7. references 73
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LABORATORy ANALySIS FOR THE DETECTION OF pROHIBITED mATERIALS IN LIvESTOCk FEED
1. general concepts 75
2. available test methods 76
3. comparison of tests 80
4. summary of tse-relevant concepts 81
5. references 82
BSE RISk AND TRADE IN ANImAL pRODUCTS AND LIvESTOCk FEEDS
1. general concepts 83
2. the effects of bse on global trade 83
3. assessing the risks of bse in trade 83
4. trade data: quality and quantity 84
5. assessing bse exposure risk 86
6. summary of tse-relevant concepts 89
7. references 89
AppENDIX 1
course contributors and staff 91
AppENDIX 2
related background reading and Web links 95
AppENDIX 3
glossary of technical terms and acronyms 101
AppENDIX 4
project summary 109
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FOREwORD
Tosupportcountrieswitheconomiesintransitionanddevelopingcountriesinthecon-trol and prevention of bovine spongiform encephalopathy (BSE), the project CapacityBuildingforSurveillanceandPreventionofBSEandOtherZoonoticDiseases,involvingcollaboration between the Food and Agriculture Organization of the United Nations(FAO), Safe Food Solutions, (SAFOSO, Switzerland) and national veterinary offices inpartnercountries,andfundedbytheGovernmentofSwitzerland.
Theaimoftheproject istobuildcapacity,establishpreventivemeasuresandana-lyserisksforBSE.PartnercountriesarethusenabledtodecreasetheirBSErisktoanacceptablelevelordemonstratethattheirBSEriskisnegligible,andtherebyfacilitateregionalandinternationaltradeundertheAgreementontheApplicationofSanitaryandPhytosanitaryMeasures (SPS)of theWorldTradeOrganization (WTO).Abriefprojectsummaryisincludedasanappendixtothiscoursemanual.
Activitiesoftheproject:• Thespecificneedsofpartnercountriesareassessed.• Fourcomprehensivecoursesto“trainthetrainers”areprovidedtoselectedpar-
ticipantstoimproveunderstandingoftheepidemiologyofandrelevantriskfactorsfor BSE and Transmissible spongiform encephalopathies (TSE) and to developspecificknowledgeandskillsforimplementingappropriatecontrols.
• Inathirdstep, in-countrycoursesareheldbytrainednationalpersonnel inthelocallanguageandaresupportedbyanexperttrainer.
FAOhasthemandatetoraiselevelsofnutritionandstandardsofliving,toimproveagricultural productivity and the livelihoods of rural populations. Surveillance andcontrol of diseases of veterinary public health importance contribute to this objec-tive.SAFOSO,aprivateconsultingfirmbasedinSwitzerland,isprovidingthetechnicalexpertiseforthisproject.
This manual is a supplement to the training course Management of transmissiblespongiformencephalopathiesinlivestockfeedsandfeeding,whichisgivenwithintheframeworkoftheproject.ThispracticalcourseistargetedatgovernmentalandindustrypersonnelwhowillcontributetothedevelopmentandimplementationofthenationalBSEsurveillanceandcontrolprogramme,andtotheBSEriskassessmentforthepart-nercountries.
Theinformationincludedinthemanualisnotintendedtobecompleteortostandonitsown.Forfurtherreading,specificreferencesareincludedattheendofthechapters.General background material and Web links, and a glossary of terms and frequentlyusedacronymsareincludedasappendices.
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ThepreparationofthismanualwasacollaborativeeffortofthetrainersoftheMan-agementoftransmissiblespongiformencephalopathiesinlivestockfeedsandfeedingcourseofferedinSwitzerlandandtheprojectstaff.Thecontentofthemanualreflectstheexpertiseandexperienceoftheseindividuals.FAOandSAFOSOaregratefultotheprofessionalspreparingthemanualandtotheGovernmentofSwitzerlandforfundingthispublic-privatepartnershipprojectinsupportofsaferanimalproductionandtrade.
Samuel C. Jutzi Ulrich kihm Director Director FAOAnimalProductionandHealthDivision SafeFoodSolutions Rome,Italy Berne,Switzerland
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COURSE OBJECTIvES
UponcompletionofthelecturesandexercisesofthecourseonManagementoftrans-missible spongiform encephalopathies in livestock feeds and feeding, of the projectCapacityBuildingforSurveillanceandPreventionofBSEandOtherZoonoticDiseases,theparticipantsshould:
• basic informationonBSEandTSEs, including transmission,pathogenesis, riskfactors,andepidemiology;
• renderingandinactivationofTSEagents;• categorization ofanimal by-productsand knowledge of the risks of animal by-
productsinanimalfeed;• modernprocesstechnology in feedandpremixmanufacturingplants, including
controlofcrosscontaminationwithanimalby-products;• internationalandnationalregulationsinfeedmanufacturing,includingguidelines
fortheuseofanimalby-products;• qualitymanagementinfeedmanufacturing;• samplingstrategiesfortestingoffeedandprinciplesofthetests;• inspectionoffeedplants,includingBSEcontrols;• globalmarketforanimalfeed,includingassessmentandcontroloftherisks.
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INTRODUCTION TO TRANSmISSIBLE SpONGIFORm ENCEpHALOpATHIES
1. TRANSmISSIBLE SpONGIFORm ENCEpHALOpATHIESTransmissible spongiform encephalopathies (TSE) are a class of neurodegenerativediseasesofhumansandanimalscharacterizedbyspongiformdegenerationofthebrainandtheassociatedneurologicalsigns.TSEsareslowlydevelopinganduniformlyfatal.
Diseasesincludekuru,Gerstmann-Sträussler-ScheinkersyndromeandCreutzfeldt-Jakobdisease(allinhumans),scrapie(insheepandgoats),felinespongiformencepha-lopathy(FSE;incats),bovinespongiformencephalopathy(BSE;incattle),chronicwast-ingdisease(CWD;incervids)andtransmissibleminkencephalopathy(TME;inmink).MostoftheseTSEshadalreadybeenreportedbeforethefirstdetectionofBSE.(Figure1)(Lasmezas,2003).
FigUre 1
year in which the various TSEs were first reported
1700 1750 1800 1850 1900 1950 2000
Variant Creutzfeldt-Jakob disease
Feline spongiform encephalopathy
Bovine spongiform encephalopathy
Chronic wasting disease
Transmissible mink encephalopathy
Gerstmann-Sträussler-Scheinker syndrome
Creutzfeldt-Jakob disease
Kuru
Scrapie
The TSE with the longest history is scrapie, which was recognized as a disease ofsheepinGreatBritainandothercountriesofwesternEuropemorethan250yearsago(DetwilerandBaylis,2003).Scrapiehasbeenreportedinmostsheep-raisingcountriesthroughouttheworldwithfewnotableexceptions(e.g.Australia,NewZealand).
Transmissible mink encephalopathy (TME) was first described in 1947. It is a rarediseaseoffarmedminkandhasbeenrecordedincountriesincludingtheUnitedStatesofAmerica(USA),Canada,Finland,GermanyandtheRussianFederation.ContaminatedfeedissuspectedtobethemainsourceofTMEinfection.
Chronicwastingdisease(CWD)incaptiveandfree-roamingNorthAmericandeerandelkwasfirstdescribedinthe1960s.Initially,caseswereonlyreportedincaptivedeerandelkinColorado(USA),butCWDincaptiveand/orfreeroamingdeer,elkandmoosehasnowbeenreportedinseveralotherstatesintheUSAandinareasofCanada.TheoriginofCWDisstillunknown.
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Scrapie, kuru, Creutzfeldt-Jakob disease, Gerstmann-Sträussler-Scheinker syn-drome,TME,andCWDarebelievedtobedistinctfromBSE.However,straintypinghasindicatedthatsomeotherTSEsarecausedby thesamestrainof theTSEagent thatcausesBSE incattle.Only fouryearsafter the initialBSEcaseshadbeendiagnosedin cattle in the United Kingdom of Great Britain and Ireland (UK), BSE in domesticcats (feline spongiform encephalopathy / FSE) was first reported. Almost all of theapproximately100FSEcasesdiagnosedworldwideoccurredintheUK.Themostwidelyacceptedhypothesis is that theaffecteddomesticcatswereexposedtoBSE infectiv-ity throughcontaminatedcommercialcat feedor freshslaughteroffal thatcontainedbrainorspinalcordfrombovineBSEcases.SeverallargecatskeptinzooswerealsodiagnosedwithFSE.Theseincludedcheetahs,lions,ocelots,pumasandtigers.AllofthelargecatsthatwerediagnosedwithFSEoutsidetheUKoriginatedfromUKzoos.It issuspected that these largecatsacquired the infectionbybeing fedcarcassesofBSE-infectedcattle.
NotlongafterBSEwasdiagnosedincattle,sporadiccasesofBSEinexoticruminants(kudus,elands,Arabianoryx,ankolecows,nyala,gemsbockandbison)werediagnosedinBritishzoos.OnezebuinaSwisszoowasalsoBSEpositive.Inthemajorityofthesecases,exposuretoanimalfeedproducedwithanimalprotein(andthereforepotentiallycontainingBSEinfectivity)waseitherdocumentedorcouldnotbeexcluded.
Moreover, there has long been concern that sheep and goats could have beenexposed to BSE, because it has been experimentally demonstrated that BSE can beorally transmitted tosmall ruminants (SchreuderandSomerville,2003). In2005, thefirstcaseofBSE inagoatwasconfirmed inFrance (Eloit etal., 2005), though therehavebeennoconfirmedBSEcasesinsheeptodate.Itisdifficulttodistinguishbetweenscrapie and BSE in sheep, as differentiation is currently not possible by clinical orpathologicalmeans.
SeveralTSEshavebeenreportedtooccurinhumans,includingtwoformsofCreut-zfeldt-Jakobdisease(sporadicCJDandvariantCJD[vCJD]),Kuru,Gerstmann-Sträus-sler-Scheinkersyndrome,aswellas fatal familial insomnia.Of these,onlyvCJDhasbeenassociatedwithBSE.SporadicCJDwasfirstidentifiedin1920asanencephalopa-thyoccurringalmostexclusivelyinelderlypatientsworldwide.TheincidenceofsporadicCJD isapproximately0.3-1.3casespermillion individualsper year,and issimilar inmostcountries.Thedurationofthediseaseisapproximatelysixmonths.Approximately80-89%ofCJDcasesarebelievedtobesporadic,10%arefamilial(aresultofaheritablemutationinthePrPgene),andtheremainderarebelievedtobeiatrogenic.
VariantCJDwasfirstreportedinMarch1996intheUK(Willetal.,1996).IncontrasttosporadicCJD,patientsareyoung(averageage29years)andthedurationofthediseaseis longer(average22months).Epidemiologically, little isknownaboutvCJD. Insomecasesthediseasewasseeningeographicalclusters,andthereareindicationsthatspe-cialconsumptionpatternsmayhaveplayedarole.Geneticfactorsmayalsoplayaroleininfection,aspatientswithclinicaldiseasehavebeenhomozygousformethionineatcodon129oftheprionproteingene.InEurope,thisgenotypeaccountsforapproximately30%ofthepopulation.
The expected course of the vCJD epidemic is difficult to predict, since importantvariablessuchashumanexposurerate,theinfectiousdose,theincubationperiodandhumansusceptibilityarelargelyunknown.Thepredictions initiallyrangedfromafewhundredtoafewmillionexpectedcases.However,thelowerpredictionsaremoreprob-
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ablebasedonthecurrentincidenceofvCJDcases(Figure2).ThelinkbetweenBSEandvCJDiscommonlyaccepted.Initially,thetemporospatial
associationoftheoutbreakssuggestedacausalrelationship.Experimentally,inocula-tionoftheBSEagentintothebrainsofmonkeysproducesfloridplaqueshistologicallyidenticaltothosefoundinthebrainsofvCJDpatients.Inaddition,theagentsassociatedwithBSEandvCJDaresimilar,bothbyglycotyping(evaluatingtheglycosylationpattern)andbystraintyping,whereastheprionsassociatedwithotherTSEs(suchassporadicCJD,scrapieandCWD)aredifferent.
2. BOvINE SpONGIFORm ENCEpHALOpATHy2.1. Origin and spread of BSEBSEwasfirstdiagnosedincattleintheUKin1986(Wellsetal.,1987).Extensiveepide-miologicalstudieshavetracedthecauseofBSEtoanimalfeedcontaininginadequatelytreated ruminant meat and bone meal (MBM) (Wilesmith et al., 1988). Although ele-mentsofthescenarioarestilldisputed(e.g.originoftheagent;Wilesmithetal.,1991;Princeetal.,2003;SSC,2001a), itappears likely thatchanges inUKrenderingproc-essesaround1980allowedtheetiologicalagenttosurviverendering,contaminatetheMBM,andinfectcattle.SomeoftheseinfectedcattlewouldhavebeenslaughteredatanolderageandthereforewouldhavebeenapproachingtheendoftheBSEincubationperiod.Potentially,theyhadnoclinicalsignsorthesignsweresubtleandwentunrec-ognized, although the cattle would have harboured infectivity levels similar to thoseseen inclinicalBSEcases.Thewasteby-products from thesecarcasseswould thenhavebeenrecycledthroughtherenderingplants,increasingthecirculatinglevelofthepathogen(whichbynowwouldhavebecomewelladaptedtocattle)intheMBM,thuscausingtheBSEepidemic.
In1989,thefirstcasesoutsidetheUK,intheFalklandIslandsandOman,wereidenti-fiedinlivecattlethathadbeenimportedfromtheUK.In1989,Irelandreportedthefirstnon-imported(“native”or“indigenous”)caseoutsidetheUK,andin1990Switzerland
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
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20
15
10
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3
10
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18
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FigUre 2
Number of vCJD cases in the Uk over time
Source:DepartmentofHealthUK(2006)
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reportedthefirst indigenouscaseontheEuropeancontinent. IndigenouscaseswerethenreportedinmanycountriesthroughoutEurope.In2001,JapanreportedthefirstindigenouscaseoutsideEurope,andthiscasehasbeenfollowedbyindigenouscasesinIsraelandNorthAmerica.1
2.2. EpidemiologyCattletestingpositiveforBSEhaverangedfrom20monthsto19yearsofage,althoughmostofthecasesarebetween4and6yearsofage.Abreedorgeneticpredispositionhasnotbeenfound.MostcasesofBSEhavecomefromdairyherds,likelyduetodif-ferences infeedingsystemswhencomparedwithbeefcattle.Additionally,beefcattlearetypicallyyoungeratthetimeofslaughter.Becausetheaverageincubationperiodisfourtosevenyears,infectedbeefcattlewillgenerallynotlivelongenoughtodevelopclinicalsigns.
Thereisnoexperimentalorepidemiologicalevidencefordirecthorizontaltransmis-sionofBSE,andthereisstillcontroversyregardingthepotentialforverticaltransmis-sion.Noinfectivityhasthusfarbeenfoundinmilk(TAFS,2007;SSC,2001b),ova,semen,or embryos from infected cattle (SSC 2002a, 2001c; Wrathall, 1997; Wrathall et al.,2002).SomeoffspringofBSEcasesintheUKwerealsoinfected,andacohortstudyofUKcattleconcludedthatverticaltransmissioncouldnotbeexcluded.However,theroleofvariationingeneticsusceptibilityorothermechanismsinthisconclusionisunclear,andnooffspringofBSEcaseshavebeenreportedwithBSEoutside theUK. Ifsomeamountofmaternaltransmissiondoesoccur,it isclearlynotenoughtomaintaintheepidemic,evenwithintheUK.
2.3. pathogenesis Intheearly1990s,infectivitystudiesofBSEincattlewereongoing.Atthattime,experi-mentalinoculationoftissuesfromBSE-infectedcattleintomicehadonlyidentifiedinfec-tivityinbraintissue.Therefore,definitionofspecifiedriskmaterials(SRM;thosetissuesmost likely to be infective) was based on scrapie infectivity studies. Scrapie replicatesprimarilyinthelymphoreticularsystem,andscrapieinfectivityhasbeenfoundinnumer-ouslymphnodes,tonsils,spleen,lymphoidtissueassociatedwiththeintestinaltractandplacenta.Duringthelaterpreclinicalphase,infectivityisfoundinthecentralnervoussys-tem(CNS).Inaddition,scrapieinfectivityhasbeendetectedinthepituitaryandadrenalglands,bonemarrow,pancreas,thymus,liverandperipheralnerves(SSC,2002b).
The first resultsofBSEpathogenesisstudies, inwhichcalveswere intracerebrallyinoculatedwithtissuefromBSEfieldcasesandfromcattleexperimentallyinfectedbytheoral route,becameavailable in themid-1990s (Wellsetal.,1996;1998). Incattleexperimentally infectedby theoralroute,BSE infectivityhasbeen found in thedistalileumatspecificintervalsduringtheincubationperiod,startingsixmonthsafterexpo-sure(Wellsetal.,1994).Furthermore,CNS,dorsalrootgangliaandtrigeminalgangliawerefoundtobeinfectiveshortlybeforetheonsetofclinicalsigns.Recently,lowlevelsof infectivity early in the incubation period have been detected in the palatine tonsil.Inonestudy,sternalbonemarrowcollectedduringtheclinicalphaseofdiseasewasinfective;however,thisresulthasnotbeenreproduced(thereforeitmaypossiblyhavebeenduetocrosscontamination)(Wellsetal.,1999;Wells,2003).
1 CurrentthroughJanuary2007.
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2.4. TSE agentsAlthough some controversy still exists regarding the nature of the BSE agent, mostresearchersagreethataresistantprionproteinisthecauseofthedisease.Researchhasshowntheagenttobehighlyresistanttoprocessesthatdestroyothercategoriesofinfectiousagents,suchasbacteriaandviruses,andnonucleicacidhasbeenidentified.
Ineukaryoticspecies,mostcellscontainanormalprionprotein,termedPrPC(super-script “C” for “cellular”).Thisprotein isnormallydegradablebyproteases.TSEsarethoughttobecausedbyanabnormal,infectiousformofPrPC,inwhichthestericcon-formationhasbeenmodifiedandwhich ishighlyresistant toproteinasedegradation.This infectious form ismostcommonly termedPrPSc(initially for “scrapie”),butmayalsobereferredtoasPrPBSEorPrPres(fortheportionthatis“resistant”toaspecificpro-teinase,proteinaseK).Becauseprionproteinisverycloselyrelatedtothenormalcel-lularPrPCprotein,itdoesnotinducetheproductionofantibodiesininfectedanimals.
TheroleofPrPCinnormalanimalsisstillunderdiscussion.GeneticallymodifiedmicelackingthegeneforPrPC(andexpressingnoPrPC)canbeexperimentallyproduced,butthesemicehavenoobviousphysiologicalchangesthatcanbeattributedtolackingtheprotein.Theycannot,however,beinfectedexperimentallywithTSEagents.
3. mEASURES FOR CONTROL AND pREvENTION3.1. Aims of measuresTheultimateaimsofBSEcontrolandpreventionprogrammesaretoreduceexposureriskbothtocattleandtohumans(Figure3).Twolevelsofmeasuresmustthereforebeconsidered:
• thosethatblockthecycleofamplificationinthefeedchain;• thosethatpreventinfectivematerialfromenteringhumanfood.
Asaresultoftheprolongedincubationperiod,itmaybemorethanfiveyearsbetweeneffective enforcement of measures and a detectable decrease in the number of BSEcases,i.e.beforetheeffectofthemeasuresisseen.Thisintervalmaybeevenlongerifthemeasuresarenotenforcedeffectively,asisusuallythecaseforsometimeafterimplementation.
FigUre 3
Reducing BSE exposure risk to both cattle and humans
Blockamplification
EradicateBSE
Prevent the BSE agent from entering human food
Prevent animal exposure
Prevent human exposure
Recycling andamplification cycle in cattle
MeasuresIntermediate
goalsUltimate
aims
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RiskmanagementforBSEisnotgloballyharmonized.InEurope,thememberstatesoftheEuropeanUnion(EU)havecommonrulesfortheimplementationofmeasures,andothercountriesinEuropeandcountrieswantingtojointheEUareadaptingtheirmeasures accordingly. However, the implementation of these measures still variesconsiderablyfromonecountrytoanother.
3.2. measures to protect animal healthFeed bansRecognitionofMBMasasourceofinfectionledtobansonfeedingMBMtoruminantsinordertobreakthecycleofcattlereinfection(DEFRA,2004a;EC,2004;HeimandKihm,1999).Implementationofa“feedban”maymeandifferentthingsindifferentcountries.FeedscontainingMBMofruminantormammalianoriginmightbebanned,orthebanmight includeallanimalproteins (i.e.mammalianMBM, fishmealandpoultrymeal).Thebanmightprohibitfeedingofthematerialstoruminantsortoalllivestockspecies,ormightentirelyprohibituseofthematerial.
Insomecountries,afeedbanofruminantMBMtoruminantswasimplementedasthefirststep.ThebanwasthenoftenextendedtomammalianMBMduetothediffi-cultyindistinguishingbetweenheat-treatedMBMofruminantoriginandMBMofothermammalianorigin.Thisextendedbanwasgenerallyeasiertocontrolandenforce.
EvenwhennoMBMisvoluntarilyincludedincattlefeed,thereisstillariskofrecyclingtheagentthroughcrosscontaminationandcrossfeeding.ExperiencehasshownthatsmallamountsofMBMinfeedaresufficienttoinfectcattle.ThesetracesmayresultfromcrosscontaminationofMBM-freecattlefeedwithpigorpoultryfeedcontainingMBM,e.g.fromfeedmillsthatproducebothtypesoffeedinthesameproductionlines,fromtransportbythesamevehiclesorfrominappropriatefeedingpracticesonfarms.Apparently,usingflushingbatchesasasafeguardagainstsuchcrosscontaminationinfeedmills isnotsufficient.ThetracesofMBMincattlefeedthathavebeendetectedinEuropeancountriesaremostoftenbelow0.1%,whichseemstobeenoughtoinfectcattle.Therefore,aslongasfeedingofMBMtootherfarmedanimalsisallowed,crosscontaminationofcattlefeedwithMBMisverydifficulttoeliminate.Dedicatedproduc-tionlinesandtransportchannelsandcontroloftheuseandpossessionofMBMatfarmlevelarerequiredtocontrolcrosscontaminationfully. InmostEuropeancountries,abanonfeedingMBMtoallfarmanimalshasnowbeenimplemented.
Moredetailed informationonmeasures for livestock feedscanbe found insubse-quentchaptersofthiscoursemanual.
Rendering parametersRenderingofanimalby-products(e.g.bovinetissuesdiscardedattheslaughterhouse)andfallenstockintoMBM,whichisthenfedtoruminants,canrecycletheagentandallowamplification.Whenrenderingprocessesareproperlyapplied,thelevelofinfec-tivityisreduced.Ithasbeendeterminedthatbatch(ratherthencontinuous)renderingat133ºCand3barsofpressurefor20minuteseffectivelyreducesinfectivity(providingthat the particle size is less than 50 mm) although it does not completely inactivatetheagent(Tayloretal.,1994;TaylorandWoodgate,1997;2003;OIE,2005a).Therefore,using these parameters does not guarantee absolute freedom from infectivity in theMBM,especiallywhenmaterialwithhighlevelsofBSEinfectivityenterstherenderingprocess.
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More detailed information on measures for rendering can be found in subsequentchaptersofthiscoursemanual.
Specified risk materialsSpecifiedriskmaterials(SRM),aretissuesthathavebeenshown(orareassumed)tocontainBSEinfectivityininfectedanimals,andthatshouldberemovedfromthefoodand feedchains (TAFS,2004a). If thesematerialsareremovedatslaughterand thenincinerated, the risk of recycling the pathogen is markedly reduced. In addition, inordertoremoveinfectivityfurtherfromthefeedchain,carcassesfromhigh-riskcattle(e.g.fallenstock)shouldalsobetreatedasSRM.CountriesdefineSRMdifferently,anddefinitionssometimeschangeasnew informationbecomesavailable;however,mostdefinitionsincludethebrainandspinalcordofcattleover30months(Table1).
3.3. measures to prevent human exposureTheabovemeasurestoprotectanimalhealthindirectlyprotecthumanhealthbycon-trolling the amplification of the BSE agent. The most important direct measures forpreventinghumanexposure to theBSEagent in foodsaredescribed in the followingpages.
Ban of SRm and mechanically recovered meat for foodExcludingSRMandmechanically recoveredmeat (MRM) from thehuman foodchaineffectivelyminimizestheriskofhumanexposureandisthemostimportantmeasuretakentoprotectconsumers (TAFS,2004a).MRMisapastederived fromcompressed
TABLE 1. A summary of designated SRm in Europe (as of October 200�)
Species and tissue European Union Uk and portugal Switzerland
Age
CATTLE
Skull(includingbrainandeyes) >12months - >6months
Entirehead,(excludingtongue) - >6months >30months
Tonsils Allages Allages Allages
Spinalcord >12months >6months >6months
Vertebralcolumn(includingdorsalrootgangliabutNOTvertebraeoftailortransverseprocessesoflumbarandthoracicvertebrae) >24months >30months >30months(includestail)
Intestinesandmesentery Allages Allages >6months
Spleen - >6months -
Thymus - >6months -
SHEEp AND GOATS
Skull(includingbrainandeyes) >12month >12months >12months
Spinalcord >12months >12months >12months
Tonsils >12months >12months Allages
Ileum Allages Allages Allages
Spleen Allages Allages Allages
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carcasscomponentsfromwhichallnon-consumabletissueshavebeenremoved.Thesecarcasscomponentsincludebonesaswellasthevertebralcolumnwiththespinalcordanddorsalrootgangliaoftenattached.TheMRMisthenusedincookedmeatproducts,suchassausagesandmeatpies,and,ifruminantmaterialisincluded,isregardedasamajorBSEriskfactor.
BSE detection at slaughterMeasuresforminimizingrisksforhumanhealthrequiretheidentificationandelimina-tionofclinicallyaffectedanimalsbeforeslaughter,whichcanonlybeachievedthroughanadequatesurveillanceprogrammeincludinganantemorteminspectionspecificforBSE.BecausetheSRMfromclinicallyaffectedanimalsisknowntocontaininfectivity,removalanddestructionof theseanimalsprior toentering theslaughterhousehavetwoclearlypositiveeffects:
• Theriskofinfectivematerialenteringthefoodandfeedchainsisreduced.• There is lesscontaminationof theslaughterhouse,and lesspotential forcross
contaminationofnormalcarcasses.Inaddition,mostcountriesinEuropehavebeenconductinglaboratorytestingofall
slaughter cattle over 30 months of age (or even younger) for BSE since 2001 (TAFS,2004b).
Thebenefitsoftestingregularslaughtercattleare:• It identifies the very few positive animals that may not yet be showing clinical
signs.• Itdecreasestheriskofcontaminatedmaterialenteringthe foodchain in those
countrieswhereothermeasures(e.g.antemorteminspection,SRMremoval)maynotbeeffectivelyimplemented.
• Itcouldincreaseconsumerconfidenceinbeefandbeefproducts.• Itmayallowimportbanstobelifted(althoughsomeimportsbansmaybeinviola-
tionofWTOrules).Thedrawbacksare:• Itisextremelyexpensive.• Itmaygiveafalsesenseofsecuritytoconsumers.• It may diminish the incentive to implement effectively and enforce other, more
effectivemeasures(suchasantemorteminspection).• Itcouldleadtoincreasedcontaminationwithinslaughterhousesduetoprocess-
ingofagreaternumberofpositivecarcasses ifothermeasuresarenot imple-mented.
AllcurrentlyavailablemethodsfordiagnosingBSErelyonthedetectionofaccumu-latedPrPScinthebrainofinfectedanimals.Therefore,cattlemusthavealreadybeenslaughteredbeforeconfirmationofdiseasestatuscanbemade,potentiallyincreasingtheriskofcontaminationofcarcasseswithaninfectiousagent.Topreventthis,identi-ficationandremovalofclinicallyaffectedanimalsbythefarmerorveterinarianduringanantemorteminspectionareoptimalcontrolsteps.
measures to avoid cross contamination of meat with SRmIthasbeenshownthattheuseofcertaintypesofcaptiveboltgunstostuncattlepriortoslaughtercausesbraintissuetoenterthebloodstreamthatcould,bedisseminatedthroughout the carcass (including muscle). Therefore, pneumatic bolt stunning and
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pithingarenowforbiddenbymanycountriesinEuropeandelsewhere.Hygienicmeas-urestakenintheslaughterhousetoreducepotentialcontaminationofmeatwithSRMarealsoimportant.
MoredetailedinformationonSRMremovalandothermeatproductionissuescanbefoundintheCapacityBuildingforSurveillanceandPreventionofBSEandOtherZoonot-icDiseasesprojectcoursemanualentitledManagementof transmissiblespongiformencephalopathiesinmeatproduction(FAO,2007a).
3.4. On-farm measuresClassicalcontrolmeasuresforinfectiousdiseases(biosecurity,quarantine,vaccination)donotgenerallyapplytoBSE.Givenallavailableevidence,theBSEagentisnottrans-mittedhorizontallybetweencattlebutonlythroughfeed,primarilyingestionofcontami-natedMBMduringcalfhood.WhenaBSEcaseisdetected,ithasbeenshownthatothercattlewithinthatherdareunlikelytotestpositiveforBSE,despitethelikelihoodthatmanycalvesofsimilaragetothecaseallconsumedthesamecontaminatedfeed.
However,someon-farmstrategies,primarilythosethatfocusonfeedasasourceofinfection,andsomecullingprogrammesdocontributetothecontrolanderadicationofBSE.Cullingstrategiesvaryamongcountries,andoftenchangeovertime.Somediffer-entcullingstrategiesthathavebeenappliedinclude(SSC,2000;2002c).
• theindexcaseonly• allcattleonthefarmwheretheindexcasewasdiagnosed• allcattleonthefarmwheretheindexcasewasbornandraised• allcattleontheindexcasefarmandonthefarmwheretheindex casewasbornandraised• allsusceptibleanimalsontheindexcasefarm (includingsheep,goatsandcats)• “feed-cohort“(cattlethatcouldhavebeenexposedto thesamefeedastheindexcase)• “birth-cohort“(allcattlebornoneyearbeforeoroneyear aftertheindexcaseandraisedonthesamefarm)
Whileherdcullingmaybeapoliticallyexpedientmeansofincreasingconsumercon-fidenceandfacilitatingexports,itisunlikelytobeanefficientriskmanagementmeas-ure (Heim and Murray, 2004). There are significant problems in implementing suchastrategy.Farmerssee itasaradicalapproachbecause it results inaconsiderablewasteofuninfectedanimals.Althoughtheremaybesufficientcompensationforculledanimals, farmersmaynotbelieve it is reasonable tocullapparentlyhealthy,produc-tiveanimals.Inadditiontheyarelikelytolosevaluablegeneticlinesand/ortheir“life’swork”.Forthesereasons,farmersmaybelesswillingtonotifysuspectcasesifcullingoftheirentireherdcouldresult.
Evidencefromanumberofcountriesindicatesthat,inthoseherdswheremorethanonecaseofBSEhasbeendetected,theadditionalcase(s)werebornwithinoneyearoftheindexcase.Asaresult,cullingabirthcohortisamorerationalriskmanagementstrategyasitfocusesonthoseanimalswithinaherdthathavethegreatestchanceofhavingBSE.Evenso,dependingontheinitiallevelofexposureandtheoriginalsizeofthecohort,itislikelythatrelativelyfewadditionalcasesofBSEwillbedetectedinthe
Herdculling
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birthcohortofaherd indexcase.Cohortculling is,however, likely tobemuchmoreacceptabletofarmerswhencomparedwithherdculling.
3.�. Import controlThebestmeansofpreventingtheintroductionofBSEistocontroltheimportofcertainBSEriskproductsfromcountrieswithBSEorcountriesthatareatriskofhavingBSE.Mostcountriesdonotbanimportsofpotentiallyinfectivematerialsuntiltheexportingcountry has reported their first BSE case. This is usually too late, however, becausethe risk already existed before the first case was detected. Materials that should beconsideredriskyforimport(unlessappropriatesafetyconditionsaremet)includeanymammalianderivedmeals (includingMBMandotherproteinmeals), feedcontainingMBM,livecattleandoffal. Importofbeefandbeefproductsforhumanconsumption,including processed beef products, whole cattle carcasses and bone-in beef, shouldalsobecontrolled,especiallyfortheexclusionofSRM.Debonedbeefmeatisgenerallyconsideredasnon-riskyforimport.
3.�. EnforcementAlthoughimplementationofeachmeasuredecreasestheoverallriskofexposure,com-biningmeasuresdecreasestheriskmoreprofoundly(HeimandKihm,2003).Forexam-ple, feedbansimplementedinconjunctionwithanSRMbanforfeedhaveastrongerimpact. Moreover, measures must be effectively implemented and enforced. Simplyissuing a regulation or ordinance without providing the necessary infrastructure andcontrolswillnotachievethedesiredgoals.Educationofallpeopleinvolvedisrequiredatalllevelsandinallsectorsinordertoimproveunderstandingandcapacity,andthusimprovecompliance.
4. CLINICAL SIGNS OF BSEIncontrasttomanyBSEcasespicturedinthemedia,mostcattlewithBSEhavesubtlesignsofdisease.Signsareprogressive,variableintypeandseverity,andmayincludedepression,abnormalbehaviour,weightloss,sensitivitytostimuli(light,sound,touch)andgaitormovementabnormalities.Othersigns thathavebeennoted insomeBSEcasesincludereducedmilkyield,bradycardiaandreducedruminalcontractions(Braunetal.,1997).
Differential diagnoses for BSE include bacterial and viral encephalitides (e.g.bornadisease,listeriosis,sporadicbovineencephalitis,rabies),brainedema,tumors,cerebrocortical-necrosis (CCN), cerebellar atrophy, metabolic diseases and intoxica-tions,aswellasothercausesofweightlossandneurologicalabnormalities.
Becausenoneof theclinical signsarespecific (pathognomonic) for thedisease,adefinitive clinical diagnosis cannot be made. With experience, however, farmers andveterinarianscanbecomeefficientatearlyidentificationofBSEsuspects.Thesesuspi-cionsshouldalwaysbeconfirmedthroughlaboratorytesting.
�. DIAGNOSIS OF BSE�.1. BiosafetyMicroorganisms are classified by the World Health Organization (WHO) accordingto their pathogenicity for humans and animals. According to this classification, pre-cautions must be taken when handling these agents primarily to protect the people
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handling them and also to protect the general human population and livestock fromaccidentalexposure.Dependingontheclassificationofthemicroorganism,precautionsalso must be taken to protect laboratory workers and the community from possibleexposureandinfection.Thus,WHOhasdefinedfourbiosafetylevel(BL)categoriesforlaboratories.ThesecategoriescorrelatesomewhatwiththeWHOriskgroupcategories,butalsoreflectwhatisbeingdonewiththemicroorganisminthelaboratory.
Themostinternationallywell-acceptedguidelineontheclassificationsystemforandthehandlingofmicroorganismsistheWHOLaboratorybiosafetymanual(WHO,2003).Thismanualdefinestheriskgroups,therequirementsforriskassessments,andtherequirementsforeachofthelaboratoryBLs.
In2000,theEUpublishedadirectivebasedontheWHOguidelines,whichdefinesanewriskgroupforBSEandrelatedanimalTSEsbasedonBSEagentcharacteristics(e.g.limitedriskforlaboratorypersonnelandthecommunity,inabilitytoexcludeaero-sol transmission). This new risk group is called 3**, which means risk group 3 withsomealleviations.Scrapie,ontheotherhand,isstillclassifiedasriskgroup2.
AccordingtotheSwissExpertCommitteeforBiosafety,differentbiosafetylevelsarerequiredwhenhandlingBSEmaterials,dependingonthetypeofmaterial(SwissExpertCommittee for Biosafety, 2006). For example, histology and Immunohistochemistry(IHC)onformicacid-inactivatedBSEmaterialcanbeperformedinaBL1laboratory,androutineBSEdiagnosticscanbeperformedinaBL2laboratorywithsomeadditionalmeasures.Areference laboratory forTSEmustbeBL3,butsomemodificationsareallowed.Attentionshouldbepaid to the fact thatBSE laboratory requirementsoftendifferamongcountries.
�.2. Sample collectionBecauseboththehighestconcentrationofPrPScandthemostprominentrelatedlesionstendtobelocatedintheareaoftheobexregionofthebrainstem(Figure4),samplingthisregionoptimizessensitivity,regardlessofthediagnostictestmethodused.Ifthis
FigUre 4
Tissue selected for testing for BSE (histopathology and rapid tests), (s), includes the obex region (o)
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regionisnotsampledcorrectly,falsenegativeresultsmaybeobtained.Thisrequiresthatindividualscollectingsamplesarefamiliarwiththeanatomyinthisregion.
All animals clinically suspected of having BSE should be examined post mortem.Optimally,severalrepresentativeareasofthebrainofclinicalsuspectsareexamined;therefore,thewholeheadoftheanimalshouldberemovedandsenttothelaboratory.Aswell,thisallowsteststobeperformedforotherdifferentialdiagnoses.Atthelabora-tory,thebrainisremovedassoonaspossibleforfurthertestingandonehalfisfixedinformalin(forhistopathologyandIHC).Theremaininghalfofthebrainisfirstsampledforrapidtestsandthenfrozenat-20°Cor-80°C.
Incasesofemergencyslaughter,fallenstockorroutinescreening,onlythecaudalbrainstem (medulla oblongata) is generally removed for testing, without opening theskull.Thecaudalendofthebrainstemshouldbevisiblethroughtheforamenmagnumafterseparationofthehead,andaspeciallydesignedspooncanbeusedtoremovethebrainstem(includingtheobexregion)throughtheforamen.Thebrainstemisthensplitlongitudinally,andonehalffixedinformalinforhistopathologyandIHCwhiletheotherhalfisreservedandsampledforrapidtests.Thefreshtissueremainingaftersamplingforrapidtestsisthenfrozenat-20°Cor-80°C.
ForneuropathologyandIHC,tissueisfixedinformalin,inactivatedwithformicacid,andthenembeddedinparaffin.Theembeddedbrainsamplesaresectionedandplacedonglassslides.Forneuropathologicexamination,sectionsarethenstainedwithstand-ardhaematoxylinandeosin(H&E)stain.
�.3. Neuropathology and immunohistochemistryVisualizationof typicalneuropathologicchangesrequires that the tissuestructurebeintact.Thereforeitmaynotbepossibletoevaluateevenslightlyautolyticsamples(e.g.samplesfromfallenstockorcadavers,samplesimproperlyfixedfortransport).Freez-ingofsamplesalsodestroysthetissuestructure.
Aftercharacterizationofthehistopathologicfeaturespresentinasample,BSEmustbedifferentiatedfromotherneuraldiseasesshowingsimilarlesions.Theterm“spongi-form” ispurelydescriptiveand issometimesused interchangeablywithother terms,suchasvacuolation,spongiosis,spongydegenerationormicrocavitation.Vacuolationoftheneuropilcanbeseeninmanydifferentdiseasesandeveninanormalbrain,sopos-siblecausesofspongiformchangesmustbedifferentiated(e.g.normalvacuolationvspathologicalvacuolationvsvacuolationfrompostmortemartifacts).“Encephalopathy”referstothefactthatthediseaseisprimarilydegenerativeand,apartfromgliosis,doesnotshowanyinflammatorychanges.
Afterneuropathologicexamination,IHCcanbeusedtoidentifyPrPScdirectly,inthesamplebylabellingitwithspecificantibodies.Insomecases,IHCmayallowadefinitivediagnosisofBSEtobemadewhenquestionableorevennoneuropathologicchangesareseen.
However,becausethenormalPrPprotein(PrPC)present inthebraincellshasthesameaminoacidsequenceasPrPSc,antibodiesnormallyusedinIHCdetectbothPrPScandPrPC.Therefore,inordertobeabletodetermineifthereisanyPrPScpresent,thetwoproteinsmustfirstbedifferentiated.ProteinaseKisanenzymethatcausestotalproteolysisofnormalPrPC,althoughPrPScisresistanttoproteolysisbyproteinaseKtoalargeextent.OnlysmallpartsatthebeginningandattheendofPrPScaredigestedand the remaining part, generally referred to as the core fragment or PrPres, is still
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detectedbytheantibodies.Therefore,proteinaseKisusedinIHCtodigesttotallythePrPCpresentinthesample,ensuringthatanyPrPdetectedwillbePrPSc.Withoutthisstep, samples could yield a false positive result because of the detection of normalPrPC.Similarly,incompletedigestioncouldleadtofalsepositiveresults.
Formostantibodiesusedintesting,therespectiveepitopeonPrPisnotaccessibleinthenativePrPconformation.Therefore,anadditionalsteptodemasktheappropriateepitopeonPrPres isrequired.Demaskingcanbeaccomplishedbydenaturationoftheproteinorbyusingnon-specificproteases.
�.4. Rapid BSE tests TestsareavailabletoanalyseBSEsuspectmaterialsrapidly(OIE,2005b).Whichrapidtestsarelicensedandapprovedinvariouscountriesthroughouttheworldarevariableandlistsareconstantlybeingupdated(EuropeanFoodSafetyAuthority,2005).
AllcurrentlylicensedBSErapidtestshaveseveralthingsincommon.First,theyusematerial from the brainstem, i.e. they are post mortem tests. Second, current rapidtestsarebasedonthesameprinciplesofhomogenization,proteinaseKdigestion(withthe exception of the IDEXX HerdChek BSE Antigen EIA), and detection. Although theprinciplesof thesestepsaresimilaramongtests, therearesignificantdifferences intheexecution.Thematerialsandproceduresarespecifictoeachtestsystemandtestperformance is validated under these specific conditions, thus protocols cannot bemodifiedorinterchangedamongtests.
Initially,thesampleofcentralnervoussystem(CNS)materialmustbehomogenizedwith a specific buffer containing stabilizers and detergents. After homogenization,proteinaseKisusedtodigestthePrPC(withtheexceptionoftheIDEXXHerdChekBSEAntigenEIA)andtheepitopeisdemasked.Then,theproteinaseKresistantfragmentofPrPSc,ifpresent,isdetectedwithspecificmonoclonalorpolyclonalantibodiesusingwesternblotorenzymelinkedimmunosorbentassay(ELISA)technology.
Althoughtherearedifferencesbetweenthetests,theoverallperformance(sensitivityandspecificity)iscomparable.Greatdifferencescanbefoundinthehandlingandtheversatilityofthetestsforhighandlowthroughputlaboratoryset-ups.
�.�. New developmentsWorkisconstantlybeingdoneonthedevelopmentofnewrapidtests.Newtestsmaybebasedontherefinementofanestablishedprocedureoronthereplacementofproce-duresbycompletelynewconcepts.
All new tests are still based on post mortem sampling as they use brain materialfromtheobexregion.Ofcourse,theabilitytodiagnoseBSEantemortemwouldbeahugeadvantage,andmuchresearchisbeingdoneinthisfield.Reportsonpossibleantemortemtestsarepublishedregularly.However,noneofthesetestshassofarpassedthe validationprocess,andan imminentbreakthrough inantemortem testing isnotforeseen.
DiagnosisofTSEsiscoveredindepth intheCapacityBuildingforSurveillanceandPreventionofBSEandOtherZoonoticDiseasesprojectcoursemanualDiagnosticTech-niquesfortransmissiblespongiformencephalopathies(FAO,2007).
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�. SURvEILLANCE SySTEmS�.1. Objectives of surveillance ThetwomajorobjectivesforBSEsurveillancearetodeterminewhetherBSEispresentinthecountryand,ifpresent,tomonitortheextentandevolutionoftheoutbreakovertime. In this way, the effectiveness of control measures in place can be monitoredandevaluated.However, thereportednumberofBSEcases inacountrycanonlybeevaluatedwithinthecontextofthequalityofthenationalsurveillancesystemandthemeasurestaken.BSEriskcanstillexist inacountry,evenifnocasesarefoundwithsurveillance.Surveillanceaimstosupplementthemorecomprehensivedataprovidedbyariskassessment(HeimandMumford,2005).
Generalguidelinesfordiseasesurveillanceandspecificguidelinesforanappropri-ate levelofBSEsurveillancefor thedifferentcategoriesofnationalriskareprovidedintheOIETerrestrialAnimalHealthCode(OIE,2005c,d).Theserecommendationsareconsidered by the WTO (WTO; World Trade Organization, 1994) and the internationalcommunityastheinternationalstandards.
�.2. passive surveillanceInmostcountriesBSEislistedasanotifiabledisease,whichisabasicrequirementforafunctioningpassive(aswellasactive)surveillancesystem.However,somecountrieshavenonationalpassivesurveillancesystemforBSE,oronlyaweaksystem.
Until1999,BSEsurveillanceinallcountrieswaslimitedtothenotificationofclinicallysuspectedcasesbyfarmersandveterinarians(andothersinvolvedinhandlinganimals)totheveterinaryauthorities(passivesurveillance).Itwasassumedthatthiswouldallowearlydetectionofanoutbreak(HeimandWilesmith,2000).However,becausepassivesurveillancereliessolelyonthereportingofclinicalsuspectsandisdependentonmanyfactors,includingperceivedconsequencesonthefarmanddiagnosticcompetence,itisnotnecessarilyconsistentorreliable.Thus,althoughpassivesurveillance isacrucialcomponentofanyBSEsurveillancesystem,ithasbecomeincreasinglyobviousthatpas-sivesurveillancealoneisnotsufficienttoestablishtherealBSEstatusofacountry.
Forapassivesystemtofunctioneffectively,severalfactorsmustbeinplace:
Veterinarystructure: Thediseasemustbenotifiable.Casedefinition: A legal definition of BSE must exist and must be broad
enoughtoincludemostpositivecases.Diseaseawareness: Theappropriate individuals (farmers,veterinarians)must
beabletorecognizeclinicalsignsofthedisease.Willingnesstoreport: There must be minimal negative consequences to the
identificationofapositivecaseatthefarmlevelandmeas-uresmustbeconsidered“reasonable”.
Compensationscheme: Thecostsofculledanimalsmustbereasonablycompen-sated.
Diagnosticcapacity: Theremustbeadequatelaboratorycompetence.
Becausethesefactorsvarygreatly,bothamongcountriesandwithincountriesovertime,theresultsofpassiveBSEsurveillancesystemsaresubjectiveandevaluationandcomparisonofreportednumbersofBSEcasesmustbemadecarefully.
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�.3. Active surveillanceTooptimizeidentificationofpositiveanimalsandimprovethesurveillancedata,thosepopulationsofcattlethatareatincreasedriskofhavingBSEshouldbeactivelytargetedwithinanationalsurveillancesystem.Withtheintroductionoftargetedsurveillanceofcattleriskpopulationsin2001,alargenumberofcountriesinEuropeandalsothefirstcountriesoutsideEuropedetectedtheirfirstBSEcases.
Cattlewithsignsofdiseasenon-specifictoBSEandcattlethatdiedorwerekilledforunknownreasonsmaybedefinedindifferentcountriesassickslaughter,emergencyslaughter,fallenstockordownercows.TheprobabilityofdetectingBSE-infectedcat-tleishigherinthesepopulations,asitmayhavebeenBSEthatledtothedebilitation,death,cullorslaughteroftheseanimals.ManyofthesecattlemayhaveexhibitedsomeoftheclinicalsignscompatiblewithBSE,whichwerenotrecognized.Theexperienceofmanycountriesinthelastyearshasshownthat,afterclinicalsuspects,thisisthesec-ondmostappropriatepopulationtotargetinordertodetectBSE.Targetedsurveillanceaimstosamplecattleintheseriskgroupsselectively,andtestingoftheseriskpopula-tionsisnowmandatoryinmostcountrieswithBSEsurveillancesystemsinplace.
Healthycattle Routineslaughter
Cattlewithnon-specificsigns(e.g. Sick/emergencyslaughter,weightloss,lossofproduction)and fallenstock,downercowscattlethatdiedforunknownreasons(onthefarm,duringtransport)
CattlewithspecificsignsofBSE BSEsuspects(orsuspicionofBSE)
Theageofthepopulationtestedisalsoimportant,astheepidemiologicaldatashowthatcattleyoungerthan30monthsrarelytestpositiveforBSE.Therefore,targetedsur-veillanceaimstosamplecattleselectivelyover30monthsofageintheriskpopulations,whichmaybeidentifiedonthefarm,attransportorattheslaughterhouse.
However,despite the fact that correctly implementedsamplingof riskpopulationswouldhypotheticallybesufficient toassessBSE inacountry, testingasubsampleofhealthyslaughteredcattleshouldbeconsidered.Thisisneededtominimizediversionofquestionablecarcassestoslaughter,i.e.toimprovecompliance.Iffarmersareawarethat randomsampling isoccurring,andwhen theprobabilityofbeing tested is largeenough,theyarelesslikelytosendsuspectanimalsdirectlytoslaughter.
Thespecificsurveillanceapproachesvaryamongthedifferentcountries.TheEUandSwitzerlandaretestingtheentireriskpopulationover24and30monthsofage,respec-tively.IntheEU,additionally,allcattlesubjecttonormalslaughterover30monthsofage are currently tested, whereas in Switzerland a random sample of approximately5%istested.CountriesoutsideEuropehaveimplementedavarietyofdifferenttestingsystems.FromtheexperiencesgainedinEurope,itisclearthatitismostefficienttoensuretheeffectiveimplementationofpassiveandtargetedsurveillanceinriskpopula-tionsratherthantofocusontestingoftheentirenormalslaughterpopulation.
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PreventionofBSEandOtherZoonoticDiseasesprojectcoursemanualentitledEpide-miology,surveillance,andriskassessmentfortransmissiblespongiformencephalopa-thies(FAO,2007).
�. RISk ASSESSmENT�.1. BSE status and international standardsFora longtime,BSEwasconsideredaproblemexclusivelyof theUK.Evenafter thedetectionofBSEcasesinseveralcountriesoutsidetheUK,theriskofhavingBSEwascategoricallydeniedbymanyothercountries.Onlyaftertheintroductionofactivesur-veillancedidseveral“BSE-free”countriesdetectBSE.
Before2005,theOIEdescribedfiveBSEcategoriesforcountries,butinMay2005anewBSEchapterwasadopted(OIE,2005d)reducingthenumberofBSEstatuscatego-riestothefollowingthree:
•Country,zoneorcompartmentwithanegligibleBSErisk•Country,zoneorcompartmentwithacontrolledBSErisk•Country,zoneorcompartmentwithanundeterminedBSEriskAccording to the OIE, a primary determinant for establishing BSE risk status of a
country,zoneorcompartmentistheoutcomeofascience-basednationalriskassess-ment.Thisassessmentmaybequalitativeorquantitative,andshouldbebasedontheprinciplesgivenintheCodeChapters1.3.1and1.3.2onRiskanalysisandtheAppendix3.8.5 on Risk analysis for BSE (OIE, 2005 e,f,g). The OIE Code Chapter on BSE (OIE,2005d) lists the followingpotential factors forBSEoccurrenceandtheirhistoricper-spectivethatmustbeconsideredinsuchanassessment:
Release assessment2
• theTSEsituationinthecountry• productionandimportofMBMorgreaves• importedliveanimals,animalfeedandfeedingredients• importedproductsofruminantoriginforhumanconsumptionandforinvivouse
incattleIn addiction, surveillance for TSEs and other epidemiological investigations (espe-
cially surveillance for BSE conducted on the cattle population) should be taken intoaccount.
Exposure assessment: • recyclingandamplificationoftheBSEagent• the use of ruminant carcasses (including from fallen stock), by-products and
slaughterhousewaste,theparametersoftherenderingprocessesandthemeth-odsofanimalfeedmanufacture
• thefeedingbansandcontrolsofcrosscontaminationandtheirimplementation• thelevelofsurveillanceforBSEandtheresultsofthatsurveillance
In addition to an assessment of BSE risk, the OIE status categorization for BSEincludesevaluationofsomeofthemeasuresinplaceinthecountry.Accordingtothe
2 In2006,theOIEBSEchapterwasmodifiedsothatonlyBSE,andnototherTSEs,isincludedintheexposureassessment.
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OIECode,factorsevaluatedintheestablishmentofBSEstatusshouldinclude:• theoutcomeofariskassessment(asdescribedabove)• disease awareness programmes to encourage reporting of all cattle showing
clinicalsignsconsistentwithBSE• compulsorynotificationandinvestigationofallcattleshowingclinicalsignscon-
sistentwithBSE• examinationinanapprovedlaboratoryofbrainsamplesfromthesurveillanceand
monitoringsystem.
�.2. The geographical BSE risk assessmentThegeographicalBSEriskassessment(GBR)isaBSEriskassessmenttooldevelopedby theScientificSteeringCommitteeof theEuropeanCommissionandbasedonOIEassessmentcriteria.TheGBRisaqualitativeindicatorofthelikelihoodofthepresenceofoneormorecattlebeinginfectedwithBSE,atagivenpointintimeinacountry,andhasbeenappliedtoanumberofcountriesthroughouttheworld.Themethodisaquali-tativeriskassessment,whichusesinformationonriskfactorsthatcontributeeithertothepotentialforintroductionofBSEintoacountryorregionortotheopportunityforrecyclingof theBSEagent inacountryorregion.The followingquestions,relatedtoreleaseandexposure,areansweredthroughtheGBR:
• Wastheagentintroducedintothecountrybyimportofpotentiallyinfectedcattleorfeed(MBM),andifsotowhatextent?
• Whatwouldhappeniftheagentwereintroducedintotheanimalproductionsys-tem,i.e.woulditbeamplifiedoreliminated?
Beforethedetectionofthefirstcasesinmany“BSE-free”countries,theGBRshowedthatariskcouldbepresent.Thisconfirmedtheconceptthataserious,comprehensiverisk assessment must be carried out to estimate the extent of the BSE problem incountries.
Thus, decisions on preventive measures should be based on such a detailed riskassessment, whether it is the GBR or another science-based assessment based onOIErecommendations.Nocountryshouldwaituntilthefirstcaseoccursbeforetakingpreventivemeasures.ThereremainmanycountrieswithanunknownBSErisk.Inordertominimizeimportrisksfromthesecountries,furtherriskassessmentsareneededtoevaluatetherealBSEdistributionworldwide.
RiskassessmentforTSEsiscoveredindepthintheCapacityBuildingforSurveillanceandPreventionofBSEandOtherZoonoticDiseasesprojectcoursemanualEpidemiol-ogy,surveillanceandriskassessmentfortransmissiblespongiformencephalophathies(FAO,2007c).
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transmissible spongiform encephalopathy agents. Terrestrial Animal Health Code, Appendix
3.6.3.http://www.oie.int/eng/normes/mcode/en_chapitre_3.6.3.htm
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OIE. 2005d.Bovinespongiformencephalopathy.TerrestrialAnimalHealthCode,Chapter2.3.13.http://www.oie.int/eng/normes/MCode/en_chapitre_2.3.13.htm
OIE.2005e.Generalconsiderations(riskanalysis).TerrestrialAnimalHealthCode,Chapter1.3.1.
http://www.oie.int/eng/normes/MCode/en_chapitre_1.3.1.htm
OIE. 2005f. Import risk snalysis. Terrestrial Animal Health Code, Chapter 1.3.2. http://www.oie.
int/eng/normes/MCode/en_chapitre_1.3.2.htm
OIE. 2005g. Factors to consider in conducting the bovine spongiform encephalopathy risk
assessment recommended inchapter2.3.13.TerrestrialAnimalHealthCode,Appendix3.8.5.
http://www.oie.int/eng/normes/MCode/en_chapitre_3.8.5.htm
prince mJ, Bailey JA, Barrowman pR, Bishop kJ, Campbell GR, wood Jm.2003.Bovinespongiform
encephalopathy.RevscitechOffintEpiz22(1),37-60
Schreuder BE, Somerville RA.2003.Bovinespongiformencephalopathyinsheep?RevscitechOffintEpiz22(1),103-120
1�
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spongiform
encephalopathies
SSC (Scientific Steering Committee of the European Commission).2000.OpinionoftheScientific
SteeringCommitteeonBSE-relatedcullingincattle.Adoptedatthemeetingof14/15September
2000.http://europa.eu.int/comm/food/fs/sc/ssc/out138_en.pdf
SSC.2001a.OpiniononhypothesesontheoriginandtransmissionofBSE.AdoptedbytheScientific
SteeringCommitteeatitsmeetingof29-30November2001.http://europa.eu.int/comm/food/fs/
sc/ssc/out236_en.pdf
SSC. 2001c. Opinion on the six BARB BSE cases in the UK since 1 August 1996. http://europa.
eu.int/comm/food/fs/sc/ssc/out237_en.pdf
SSC.2001b.SafetyofmilkwithregardtoTSE:stateofaffairs.http://europa.eu.int/comm/food/fs/
sc/ssc/out175_en.html
SSC.2002a.Thesafetyofbovineembryos.AmendmenttotheSSCopinionof18-19March1999
onthepossibleverticaltransmissionofbovinespongiformencephalopathy(BSE).http://europa.
eu.int/comm/food/fs/sc/ssc/out263_en.pdf
SSC. 2002b. Update of the opinion on TSE infectivity distribution in ruminant tissues. Initially
adoptedbytheScientificSteeringCommitteeatitsmeetingof10-11January2002andamended
atitsmeetingof7-8November2002.http://europa.eu.int/comm/food/fs/sc/ssc/out296_en.pdf
SSC.2002c.OpinionoftheSSContheadditionalsafeguardprovidedbydifferentcullingschemes
under the current conditions in the UK and DE. Adopted on 11 January 2002. http://europa.
eu.int/comm/food/fs/sc/ssc/out242_en.pdf
Swiss Expert Committee for Biosafety. 2006. http://www.umwelt-schweiz.ch/buwal/eng/
fachgebiete/fg_efbs/index.html
TAFS (International Forum for TSE and Food Safety).2004a.TAFSpositionpaperonspecifiedrisk
materials. http://www.tseandfoodsafety.org/position_papers/TAFS_POSITION_PAPER_SPECIFI
ED%20RISK%20MATERIALS.pdf
TAFS.2004b.TAFSpositionpaperontestingofcattleforBSE–Purposeandeffectiveness.http://
www.tseandfoodsafety.org/position_papers/TAFS_POSITION_PAPER_ON%20TESTING%20OF%
20CATTLE.pdf
TAFS.2007.TAFSpositionpaperon thesafetyofbovinemilkandbovinemilkproducts”.http://
www.tseandfoodsafety.org/position_papers/TAFS_POSITION_PAPER_ON_MILK.pdf
Taylor Dm, Fraser H, mcConnell I, Brown DA, Brown kL, Lamza kA, Smith GRA. 1994.
Decontamination studies with the agents of bovine spongiform encephalopathy and scrapie.
ArchVirol139,313–326
Taylor Dm, woodgate SL.1997.Bovinespongiformencephalopathy:thecausalroleofruminant-
derivedproteinincattlediets.RevscitechOffintEpiz16,187–198
Taylor Dm, woodgate SL.2003.Renderingpracticesandinactivationoftransmissiblespongiform
encephalopathyagents.RevscitechOffintEpiz22(1),297-310
wells GA.2003.PathogenesisofBSE.VetResCommun.Suppl1,25-28
wells GA, Scott AC, Johnson CT, Gunning RF, Hancock RD, Jeffrey m, Dawson m, Bradley R.1987.
Anovelprogressivespongiformencephalopathyincattle.VetRec121(18),419-420
wells GAH, Dawson m, Hawkins SAC, Green RB, Dexter I, Francis mE, Simmons mm, Austin AR,
Horigan mw. 1994. Infectivity in the ileum of cattle challenged orally with bovine spongiform
encephalopathy.VetRec135(2),40-41
wells GAH, Dawson m, Hawkins SAC, Austin AR, Green RB, Dexter I, Horigan mw, Simmons
mm. 1996. Preliminary observations on the pathogenesis of experimental bovine spongiform
encephalopathy. In: Bovine spongiform encephalopathy: the BSE dilemma. Ed. C.J. Gibbs,
SeronoSymposia,Norwell,USASpringer-Verlag,NewYork,Inc.pp.28-44
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and feeding
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wells GA, Hawkins SA, Green RB, Austin AR, Dexter I, Spencer yI, Chaplin mJ, Stack mJ, Dawson
m. 1998. Preliminary observations on the pathogenesis of experimental bovine spongiform
encephalopathy(BSE):anupdate.VetRec142(5),103-106
wells GA, Hawkins SA, Green RB, Spencer yI, Dexter I, Dawson m. 1999. Limited detection
of sternal bone marrow infectivity in the clinical phase of experimental bovine spongiform
encephalopathy(BSE).VetRec144(11),292-294
wHO (world Health Organization).2003.Laboratorybiosafetymanual.Secondedition(Revised).
ReferencenumberWHO/CDS/CSR/LYO/2003.4.http://www.who.int/csr/resources/publications/
biosafety/Labbiosafety.pdf
wilesmith Jw, wells GA, Cranwell mp, Ryan JB. 1988. Bovine spongiform encephalopathy:
epidemiologicalstudies.VetRec123(25),638-644
wilesmith Jw, Ryan JB, Atkinson mJ.1991.Bovinespongiformencephalopathy:epidemiological
studiesontheorigin.VetRec128(9),199-203
will RG, Ironside Jw, Zeidler m, Cousens SN, Estibeiro k, Alperovitch A, posers S, pocchiari m,
Hofman A, Smith pG.1996.AnewvariantofCreutzfeldt-JakobdiseaseintheUK.Lancet347,
921–925
wrathall AE.1997.Risksoftransmittingscrapieandbovinespongiformencephalopathybysemen
andembryos.RevscitechOffintEpiz16(1),240-264
wrathall AE, Brown kF, Sayers AR, wells GA, Simmons mm, Farrelly SS, Bellerby p, Squirrell
J, Spencer yI, wells m, Stack mJ, Bastiman B, pullar D, Scatcherd J, Heasman L, parker J,
Hannam DA, Helliwell Dw, Chree A, Fraser H. 2002. Studies of embryo transfer from cattle
clinicallyaffectedbybovinespongiformencephalopathy(BSE).VetRec150(12),365-378
wTO (world Trade Organization).1994.Agreementonsanitaryandphytosanitarymeasures.FinalActoftheUruguayRound,Article5.http://www.wto.org/english/docs_e/legal_e/15-sps.pdf
21
Overview:
Implementation
of transmissible
spongiform
encephalopathy
measures for
livestock feeds
OvERvIEw: ImpLEmENTATION OF TRANSmISSIBLE SpONGIFORm ENCEpHALOpATHy mEASURES FOR LIvESTOCk FEEDS
1. GENERAL CONCEpTSCurrently, it is well accepted that cattle are exposed to the BSE agent through theingestionofcontaminatedfeed.Therefore,akeymeasureinpreventingthespreadandrecyclingof theBSEagent is toprevent ruminant-derivedproteins frombeing fed toruminants.Ultimately,thisisthesimplegoalofanyfeedban,however,achievingthisgoalisnotsosimple.ExperienceinEuropeandelsewherehasshownthataseriesofeffectivemeasuresmustbeimplementedtoassurethatthisgoalismet.
When feed bans were first introduced in Europe, the goal of preventing ruminantmaterialfrombeingfedtoruminantswaslogicallyimplementedintheleastdisruptivemannerpossible(i.e.ruminanttoruminantbansormammaltoruminantbans).Later,“flushing”batches(batchesoffeedprocessedortransportedinbetweenfeedbatchescontainingprohibitedandnon-prohibitedmaterials)were introducedtoreducetracesof prohibited materials from the equipment and reduce cross contamination. ThesemeasuresdoindeedreducetheriskofexposureofcattletotheBSEagent;however,thecontinuedappearanceofanimalswithBSEthatwerebornaftertheimplementationoftheseinitialbans(animalsbornaftertheban,or“BAB”)showedthatthemeasureswereinsufficient(HeimandKihm,2003).
Ithasbecomeclearthatacomplementarysystemofintegratedfeedcontrolmeas-ures must include (1) a ban on including specified risk material (SRM; those animaltissuesmostlikelytocontainTSEinfectivity,includingbovinefallenstock)infeeds,(2)strictfeedbansthatareeffectivelyenforced,and(3)controlofcrosscontaminationatevery step along the feed production chain from transport of raw materials throughfeedingpracticesonthefarm,inordertoultimatelypreventexposureofruminantstopotentialinfectivity(HeimandKihm,2003).Inaddition,restrictionsonimportsofriskyproductsmustbeevaluated,toprevententryorre-entryofinfectivematerial.Enforce-mentandcontrolofallmeasuresthroughself-regulationandexternalauditsiscrucial.Finally,educationanddiseaseawarenessmustbepromotedinordertopromotecom-pliancewiththemeasuresateverystepalongthefeedproductionchain, includingatthefarmlevel.
ExactlywhichmeasuresareimplementedinacountrywilldependonnationalBSErisk(asdeterminedbyanationalBSEriskassessment),economics,trade,andcapacityavailabletoeffectivelyenforcethemeasures.Insomecases,morerestrictivemeasuresmaybeeasier toenforce,and thereforemaybemoreeconomically justifiablebutallmeasuresultimatelyaimtopreventtheingestionoftheBSEagentbyruminants.
2. BAN ON SRm IN FEEDSBecauseSRMpotentiallycontainsthehighestBSEinfectivity,itshouldbeexcludednotonlyfromthehumanfoodchain,butalsofromthefeedchain,atminimumforruminantspeciesbutoptimallyforallanimals.RenderingofSRM,evenatthestandardprocessing
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parametersof133ºCand3barsofpressurefor20minutes,doesnotentirelyinactivatetheagent(TaylorandWoodgate,2003).ThereforeremovalandsubsequentdestructionofallSRM(includingfallenstockandBSEsuspectanimals)isaveryeffectivemethodforexcludingthisinfectivityfromtheBSErecyclingsystemandsubstantiallyreducingtheriskofintentionalorinadvertentexposureofruminants.Controlsattheslaughter-house(aswellasattherenderingplantinthecaseoffallenstock)mustbeinplacetoassuretheappropriateseparationanddisposalofthedifferenttypesofmaterial.
3. SCOpE OF FEED BANSCurrently, different countries have different bans, i.e. different rules regarding whatspecificmaterialsareprohibitedinfeedsandforwhatspeciesbutallbansaimtoulti-mately prevent the ingestion of ruminant material by ruminants. Feed bans directedatparticulargroupsofanimals (ruminant to ruminant,mammalian to ruminant)aregenerally more difficult to implement and enforce than those with a broader scope(mammalian tomammalian,ormammalian toall livestock)because, inanyagricul-turalsystem,thepresenceofmaterialandfeedsprohibitedforonespeciesandnotforothersincreasestheriskforcrosscontaminationorcrossfeeding.Moreover,availablefeedtestsaregenerallymoreeffectiveatdistinguishingbetweenmaterialsthatareverydifferent (e.g.plants vs.animals,or fishvs. terrestrialanimal) thanatdifferentiatingbetweenmaterialsfromdifferentmammalianspecies.
Thus,takingintoconsiderationnationalTSErisk,insomecountriesitmaybemorefeasible to implement a broader ban. However, broader bans have greater economicconsequences, as more animal by-products must be alternately disposed of and, insomecases,substantialchangesinthemanagementofthefeedproductionlinesarerequired.
4. CONTROL OF CROSS CONTAmINATIONThe importance of cross contamination has been emphasized with the continuedappearance of BAB animals in Europe. It is known that as little as one milligram ofinfectivebrainmaterialissufficienttoinfectacalf(DannyMatthews,VeterinaryLabora-toriesAgency,UK,personalcommunication,2005).Intheproductionoffeedswithbatchsizesofaboutonetonne,eventhesmallamountsofcrosscontaminationthatnormallyoccurcouldallowthisamountofmaterialtobepresentinsubsequentbatches.There-fore,incountrieswithoutotheradequatemeasures(suchasabanonSRM)thisamountofcrosscontaminationcouldleadtoexposure(andpotentiallyinfection)ofcattle.
Currently,itisbelievedthatdedicatingseparateproductionlinesforfeedscontainingprohibitedmaterialsandthosenotcontainingprohibitedmaterials (dependingonthefeedbaninplace)isthemosteffectivemeasureforpreventingthispotentialexposure.Alternatively, entirely separate plants may be established. Certainly, if feed for petanimals isproducedusinganimal-derivedmaterials, theseproduction linesmustbeseparate.Theextentof lineseparationforotherlivestockfeedswillbedependentonthe particular feed ban in place. In addition, control of cross contamination must beimplementedateachstepalongthefeedproductionchainfromhandlingrawmateri-als throughproduction, transport,andstorage, to feedingon the farm.This requiresadequaterecord-keepingandeducationofpersonnelinalltheoperationsinvolved.
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�. ImpORT RESTRICTIONSThespreadofBSEtocountries throughout theworldhasbeenattributed to trade inlivecattle,animalby-products(primarilymeatandbonemeal/MBM)andfeedscontain-ing(orpotentiallycontaining)MBM.ThisriskisnotlimitedtoexportingcountriesthathavereportedBSEcases.Therefore,importingcountriesmustnotonlyevaluatetheirdomesticriskbutalsotheriskposedbyanyimportsoftheseriskyproducts.
�. ENFORCEmENTInordertobeeffectiveatreducingrisk,allimplementedmeasuresmustbecontrolledandenforcedthroughasystemofcontrolsandauditsintegratedateverystepalongthefeedproductionchain.Asystemforsamplingandanalysisoffeedsandfeedingredientstodetectprohibitedmaterialswhichmaybepresentduetonon-compliancewiththefeedbanorowingtocrosscontaminationmustalsobeinplace,whichincludestestingofbothdomesticallyproducedproductsandimports.Thetestingmethodchosenmustbeappropriatenotonlytothespecificfeedbaninplace,butalsototheprocessparam-etersthatwereusedorpotentiallyusedinproduction.
Thesebasicconceptsaredevelopedinfurtherdetail,inparallelwithcurrentgeneralrenderingandlivestockfeedproductionconcepts,inthefollowingcoursemanualchap-ters.Attheendofmanychapters,bulletpointsemphasizetheTSE-relevantconceptsfromtheinformationpresentedwithinthechapter.
�. REFERENCESHeim D, kihm U. 2003. Risk Management of transmissible spongiform encephalopathies in
Europe.RevscitechOffintEpiz22(1),179-199
Taylor Dm, woodgate SL.2003.Renderingpracticesandinactivationoftransmissiblespongiform
encephalopathyagents.RevscitechOffintEpiz22(1),297-310
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protein use in
livestock feeding
Protein use in livestock feeding
1. GENERAL CONCEpTS Allanimals requirecertainbasicnutrients, includingenergy (from fatsandcarbohy-drates),protein,mineralsandvitamins.Compoundfeedsareformulatedtoprovideallor most of these nutritional requirements for a particular species and/or productionclassoflivestock.Itisimportanttoconsiderproductionclasswhenformulatingrations,becauseasananimalgrowsmoreenergyisneededformaintenanceofthelargerbodymassand tosupportan increasingproportionof fatdeposition.Thus,younggrowinganimalshavegreaterrequirementsformanynutrientsthandoolderanimals.Similarly,classesofhigh-producinganimals(suchaslactatingdairycattle)willalsohavehighernutritionalrequirements.
In general, the protein requirements for animals are given as some amount ofprotein (or sometimes of specific amino acids) per unit of time, usually the amountrequiredperday.Proteinrequirementsareusuallyalsoexpressedasaconcentrationwithin the ration (diet),usuallyasg/kgof the rationas fed.Aswithothernutritionalrequirements,proteinrequirementsdiffergreatlydependingon livestockspeciesandproductionclass.Inolderanimalsboththerequiredproteinconcentrationoftherationand the protein:energy ratio decline. In addition, in older animals the voluntary feedintakeincreases,sothattheincreasedamountofproteinrequiredcanbemetwithalowerproteinconcentrationintheration.Therefore,itisimportanttobespecificwhendescribingrequirementsforprotein,aswellasforaminoacids.AdetailedreviewoftheproteinrequirementsoflivestockisavailablefromMiller(2004).
Whenformulatingrations,othernutrientsandmicronutrientscontainedinthevari-oussourcesandsupplementsmustbeconsiderednotonlybecauseoftheirnutritionalbenefit but also because, in some cases, they may be present at detrimentally highlevels. These nutrients include the major minerals, calcium (Ca), phosphorus (P),sodium(Na),potassium(K),andchlorine(Cl),aswellasvitamins(includingvitaminB12,cholineandvitaminD)andessentialfattyacids.
1.1. protein requirements for monogastric animalsAlthough many ration formulations are described in terms of crude protein (CP;Table 1), monogastric animals do not have a requirement for crude protein as such.Instead,monogastricanimalsrequireninetotenspecificaminoacidsthattheycannotsynthezise,togetherwithasourceofaminonitrogenthatcanbeusedforthesynthesisoftheremainingaminoacids.Therefore,therationmustbeformulatedinconsiderationofthoseaminoacidsthatareessentialandthosethatarelimiting.
Essentialaminoacidsare thosethatcannotbesynthesizedandthereforemustbeprovidedbytheration.Inaddition,theaminoacidscysteineandtyrosinecanbesynthe-sizedinthebodybutonlyfromtheessentialaminoacidsmethionineandphenylalanine,respectively.Consequently,cysteineandtyrosinearenotabsolutelyrequiredifsufficientmethionineandphenylalanineareavailable,andsoaretermedsemi-essential.How-ever,ifcysteineandtyrosinearealsoprovidedintheration,thenadditionalmethionine
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andphenylalaninearenotrequired.Arginine isanessentialaminoacidforbirdsandfish but is synthesized in mammals as part of the urea cycle. However, the amountavailableforproteinsynthesismaybeinadequateasmostofthesynthesizedarginineisbrokendowntoreleaseurea.Therefore,additionaldietaryargininemaypromotegrowthinyounganimals.Incertainsituations,suchasinyounganimalsandrapidlygrowingchicks,glycineandserinemaynotbesynthesized insufficientquantities,andsoaretermedconditionallyessential.
Limitingaminoacidsarethoseessentialaminoacidsforwhichtherequirementscannotbemetbecausetheaminoacidcompositionsofthedifferentproteinsourcesinarationdonotmatchtheneedsof(i.e.arenotbalancedfor)thespecificproductionclass.Not surprisingly, animal protein sources are usually better able to match the aminoacidneedsofanimals,andsobetterabletomeettherequirements.Proteinsourcesthatcloselymatchtherequirementsofaparticularspeciesorproductionclasswellaretermedhighqualityproteinsforthatclass.Inattemptingtoformulateabalancedration,theminimalaimistomeettherequirementsforthefirsttwolimitingaminoacids.Ofcourse,anoptimallybalancedrationwillmeettheanimal’sneedsforallaminoacids,howeverthisisdifficulttoachieve.
Forpoultry,methioninepluscysteine(M+C;generallyconsideredtogetherascysteinecanbederivedfrommethionine)andlysineareusuallythefirsttwolimitingaminoacidsincommonlyusedfeedingredients.Lysinerequirementsmaybemetbycomplementinglysine-deficientcerealgrainswithalysine-richlegumeproteinsuchassoya.However,
TABLE 1. Typical crude protein (Cp) concentrations in rations for various classes of monogastric livestock species (in grams per kg air-dried feed)
Class weight/age Cp g/kg
SWINE
Starter:3weekweaning 5-10kg 240 5weekweaning 10-20kg 210
Grower 20-60kg 165
Finisher 60-90kg 140
Sows: lactating 176 pregnant 130
BIRDS
Broiler: starter 0-2weeks 230 grower 2-4weeks 210 finisher 4-7weeks 190
Rearingpullets 0-6weeks 210 6-12weeks 145 12-18weeks 120
Layinghens 160
Turkey: starter 0-6weeks 300 grower 6-12weeks 260 finisher 12+weeks 180
Breedingturkeys 160
FISH
Salmonidsfry fingerlings 550 smolt 400-460
Catfish 320-360
Source:adaptedfromMillerEL,2004.
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as proteins from both of these sources are also deficient in M+C, the mixed rationremainsM+Cdeficient.This isnormallyandmosteconomicallycorrectedbysupple-mentationwithsyntheticmethionine.
For pigs, lysine is normally the first limiting amino acid. Extensive research intodietaryrequirementsforyoungpigshasdeterminedtheidealaminoacidpatternandallowedexcessesofindispensableaminoacidstobeeliminated,resultinginamaximaloverallreductioninproteinrequiredintheserations.Consequently,thiscanappearasaproportionalincreaseinrequiredlysine.Assomeoftheanimalproteinshaveveryhighlevelsoflysine,theyareoptimalforuseinbalancingtheaminoacidcompositionofthecerealcomponentoftheserationstoachievetheidealratio.
Inthepast,mostrationformulationhasbeenbasedonthechemicallydeterminedaminoacidcontentoffeeds,i.e.established“bookvalues”representativeoftheclassratherthananalysesof the individual feedbatch.Someimprovement in theseestab-lishedvaluesmaybemadebydeterminingCPcontentofthebatchandthepublishedregressionequationsofaminoacidcontentinrelationtoCP.Anadditionalproblemisthat, at the tissue level, theaminoacidschemicallydetermined tobepresent in therationmaynotbeavailabletotheanimal.Thus,itisalsonecessarytoconsideraminoacidavailability.
1.2. protein requirements for ruminantsIn the ruminant, ingested feed is fermented by microorganisms in the rumen. Vola-tile fatty acids absorbed from the rumen and omasum provide the major part of themetabolizableenergytotheanimal.Thefermenteddigesta,aswellasruminalmicro-florathenleavetherumenandarefurtherdigestedintheabomasum(truestomach)andintestines(asinthemonogastricanimal).Themajorityofaminoacidsavailabletoruminantsareprovidedbydigestionandabsorptionofmicrobialprotein in thesmallintestine.Becausetheaminoacidbalanceofmicrobialproteinisgenerallymoresimilartothatof livestockthanarecerealgrains,theaminoacidrequirementsofruminantscanbemetatmaintenancelevelbymicrobialproteinalone.Withanincreaseinenergysupplied in the ration, extra microbial protein is produced and an increased level ofproductioncanbesustained.
However, the microbial protein yield is eventually limited by the fermented energysupply,thereforeformoderateandhighlevelsofproductionthemicrobialaminoacidsupplymustbesupplementedwithdietarysourcesofprotein,orprotectedaminoacidsthat escape degradation in the rumen. The nitrogen (N) requirements of ruminantsproducingathigherproductionlevelsarethustwofold:
1. AsourceofdegradableNtomeettheneedsoftherumenalmicrobialmicroflora.Thiscanlargelybemetbynon-proteinNsources,suchasurea,whicharecon-vertedtoammoniaintherumen.However,growthofthemicrofloraisadditionallystimulatedbyasupplyofproteinpeptides.
2. A source of non-degradable N that is later digested in the small intestine andprovidesaminoacidstocomplementthemicrobialaminoacidsandmeettissueneeds(“by-passproteins”).
Hence, importantcharacteristicsforproteinsuppliedintherationaretherateandextentofdegradationintherumen,whicheffecttheprotein’scontributionnotonlytotheammoniaandpeptideneedsofthemicroflorabutalsotothesupplyofaminoacidsformeetingtissueneeds.Considerablevariationinthesecharacteristicsexistsamong
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differentproteinsources.Anotherimportantcharacteristicofproteinsisthedigestibilityoftheundegradedproteinthatleavestherumen.Microbialproteinhasatruedigest-ibilityof85%inthesmallintestine,butvaluesforfeedproteinscanrangefrom50to90%.Finally,aswithmonogastricanimals,theaminoacidcompositionofthedigestedproteinmustalsobeconsidered.
2. pROTEIN SOURCES AND SUppLEmENTS Mostrations,especially thoseforyounggrowingorhigh-producinglivestockclasses,will require balancing with an additional protein source or protein supplement. His-torically,aninexpensivesourceofproteinformanufactureoflivestockfeedshasbeenmealsmadefromrenderedby-productsofanimals(MatthewsandCooke,2003),partic-ularlymeatandbonemeal(MBM).However,aftertheemergenceofBSEandthedirectimplicationof ruminant-derivedprotein in the transmissionandrecyclingof theBSEagent, itwasdeterminedthateffectivecontrolof thediseaserequiresrestrictionsonthefeedingofsometypesofanimal-derivedproteinstosomeorallclassesoflivestock(asdescribed in the“Overview: ImplementationofTSEmeasures for livestock feeds”chapterinthiscoursemanual).OneimportantresultoftheimplementationofthefeedbansinmanycountriesworldwidehasbeenadramaticdecreaseintheuseofMBMandotheranimal-derivedmealsforlivestockfeeding.Consequently,newsourcesofproteinarebeingsoughtandoldersourcesreconsidered.
Classesofproteinsourcesincludeanimal-derivedmeals,plantproteinsources,andsyntheticaminoacids.Thesesources,aswellasotherproteinsources thatmustbeconsideredinthecontextofTSEs,aredescribedbelow.
2.1. Animal-derived mealsInadditiontoclassicMBM,whichgenerallycontainsby-productsfrommultiplespecies(including ruminants), other sources of rendered animal protein include blood meal,meatmeal,bonemeal,andfeathermeal,aswellasmealsmadefromexclusivelyfishorpoultrymaterial.Insomecountries,dedicatedrenderingplantsproduceMBMfrompureequineorporcinematerial.Animal-derivedmealstendtohaveaminoacidcom-positionsthatmatchtherequirementsofanimals(aspreviouslydescribed),aswellasbeinghighinvitaminB12.Animal-derivedmealsarealsohighinlysine,whichisimpor-tantbecauselysineisthefirstlimitingaminoacidinfeedsformanylivestockclasses.
Unfortunately, thedefinitionsappliedtovariousmealsproducedthroughrenderingarenotalwaysconsistentbetweencountries,whichcausessomeconfusion.Forexam-ple,iftheashcontentishigh,thismayindicatethatthemealcontainssomeamountofbone,andsoitisreferredtoasMBM.Iftheashcontentisloweritmaybereferredtoasmeatmeal.Theterm“meatmeal”inthecontextofinternationaltradealsooftencoversarangeofproducts(e.g.meatmeal,MBM,bonemeal,bloodmeal,feathermeal)frommanyspecies(e.g.includingbovine,ovine,porcine,avian,pets,andwild/zooanimals).Therecanalsobeawidevariationinwhatexactlygoesintothemealthatisbeingpre-pared,notonlybetweenrenderingplantsbutalsobetweenindividualbatcheswithinaplant. Insomecases,spillageandwaste fromother industries (suchas thepet foodindustry)isalsorendered.Somegeneraldescriptionsaregivenhere.
Meatandbonemeal(MBM)hasawell-balancedaminoacidprofileand,priortotheappearance of BSE, was considered an excellent source of supplemental protein foranimalfeeds.Itiswellsuitedforfeedingmonogastricanimals,asitisnotonlyawell-
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balancedproteinsource,butalsoasourceofavailablecalcium,phosphorusandothernutrients(e.g.potassium,magnesium,sodium).
ThedigestibilityoftheMBMproteinfractionisnormallyhigh(81to87%).Theproteinqualityislowerthanthatoffishmealorsoyabeanmeal,limitingitsusefulnessasaCPsupplementincereal-basedrationsformonogastricanimals.However,becausetheCPislessdegradableintherumencomparedtomanyothersupplementalproteinsources,inruminantsitcanbeusedtoreplacemostothersupplementalproteins.MBMhasbeenconsideredagoodsourceofby-passproteinforruminants,andparticularlyvaluableinrationsforhigh-producingdairycows.
SupplementationofrationswithMBMhasbeensuccessfullyusedtopromoteproduc-tioninotherlivestockclasses,includingfish.ReplacingsoyabeanmealorfishmealwithMBMalsomayincreaseproductioninpigs,mainlybecauseofitshighlysinecontent.
Othermeatmealsandbonemealsaredefinedaccording to therelativeconcentra-tionsofthesecomponents,andthesedefinitionsdifferwidely.Theusefulnessofthesespecificproducts for feedingvariouslivestockproductionclasseswilldependontheirexactcomposition.
Fishmealhasbeenwidelyusedasasupplementalproteinsourceformanyyears,pri-marilyformonogastricanimals.Theaminoacidqualityoffishmealisexcellentformostproductionclasses,althoughthecomposition(e.g.CP,ash,energy)canvarydependingupontheexactsubstrateandprocessingmethod.Itisoftenusedasaby-passproteinsourceforfeedinglactatingdairycattle.Themainconstraintontheuseoffishmealbythefeedindustryisitsrelativelyhighcost.Fishmealisgenerallyprocessedseparatelyfrommaterialofruminantanimals,thereforemaybeconsideredofnegligibleBSEriskifcrosscontaminationiscontrolledduringtransportandstorage.
Poultrymeal isnutritionallysimilar toMBM,but isderivedentirely fromavianspe-cies.This is important inthecontextofBSE,becausegenerallypoultryslaughterandproduction isentirelyseparatedfromthatofruminantanimals.Thus, if therenderingprocess,transport,andstoragearealsoseparated,thentheriskofpoultrymealbeingcrosscontaminatedwithruminantproteinsisextremelylow.
Feathermeal,hornmeal,andmealfromswinebristlesarealsoseparatelyavailable.These products are generally used as supplements for the protein creatine, but theirdigestibilityisquitelow.TheyaregenerallynotconsideredariskforBSEifcrosscon-taminationiscontrolledasabove.
Bloodmealmayalsobeusedasasourceofprotein.Thisproduct isalsogenerallynotconsideredarisk forBSE ifspecificstunningmethodsareforbidden,and ifcrosscontaminationiscontrolledasabove.
2.2. plant protein sourcesPlantproteinsourcesvarywidelyintheirabilitytomeetthenutritionalrequirementsoflivestock.Inalmostallcases,plantsourcesmustbecombinedtoachieveanadequatebalanceofnutrients,particularlyaminoacids.
Soybeanmealorcakeisavaluablesourceofvegetableprotein,andiswidelyusedinrationsforpoultry,pigsandruminants.Theaminoacidcompositioniscomparabletothatofmilkprotein.Whenusingsoybeanmealasasubstitute foranimalproteins incom-poundfeeds,however,itisimportanttoconsiderthatsomemineralsarepresentonlyinsmallquantities.Inaddition,althoughsoybeanmealisagoodsourceofsomevitamins,itlacksvitaminB12,whichislikelythevitaminmostcommonlylackinginpoultryrations.
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Cottonseedmealisavaluableproteinsupplementforadultcattle.Thepresenceofgossypol(apolyphenolictoxin)notonlylimitsitsusefulnessforpigs,poultryandimma-tureruminants,butalsohaspublichealthimplications.Adultruminantsareprotectedfromgossypoltoxicityduetodenaturationofthetoxinintherumen.Cottonseedmealhasaconstipatingeffectoncattle,whichisbeneficialinfeedswithhighmolassescon-tent.Cottonseedmealhasrelativelylowrumendegradabilityandisthereforeausefulsourceofby-passprotein.
Groundnut (peanut)cakeisthematerial leftafteroilextractionofgroundnuts. It isasafefeedforallclassesoflivestockandhasagoodaminoacidbalance.Formatureruminantstherearenorestrictionsontheuseofgroundnutcake.Itmaybedecorticatedorundecorticated,andthehighfibrecontentofundecorticatedcakemakesitausefulcorrectiveforcattlefeedingongrassthatislowinfibre.Theresidualoilingroundnutcake may cause soft fat in bacon pigs; therefore, the extracted decorticated meal ispreferableforpigfeeding.Becauseofthelowfibreandhighproteincontentofdecorti-catedgroundnutmeal,itisavaluableingredientinpoultryrations.
Maize gluten meal is the by-product of the wet milling of maize (corn) and has ahigherproteincontentthanmostcerealgrains.Asitisnotverypalatableitcannotbefedalone,anditsrelativelyunbalancedaminoacidcompositionrestrictsitsuseinbothpoultry and pig rations, with maximum recommended levels of 10 to 16%. However,becauseitretainstheyellowcolouringpigmentofthegrainitisavaluableadditiontopoultryrations.
Other plant sources of protein include meals and cakes of coconut, palm kernel,rapeseed,lupin(e),safflower,sesame,mustardandlinseed,aswellaspeasandbeans,eachwithspecificlimitationsontheiruse(FAO,2004).
2.3. Synthetic amino acids Syntheticaminoacidshavebeenusedforover40years,startingwithDL-Methioninepro-ducedbychemicalsynthesisinthelate1950sand60sandL-Lysineproducedbyfermen-tation in the1960s. In the late1980s,L-ThreonineandL-Tryptophanwere introduced.With progress in biotechnology, the cost of production of each amino acid has beensignificantlyreduced,akeyfactorintheexpansionofaminoaciduseinanimalfeed.
2.4. Other protein sources that must be considered in the context of TSEs WiththeemergenceofBSE,therisksofotherfeedcomponentshavehadtobeconsid-eredandpreviouslycommonfeedingpracticesre-evaluated.
Pet foodspillageoftencontainsanimal-derivedproteinsthatmaybeprohibitedforlivestockspeciesbecause inmanycountriespet food isexemptfromaspectsof feedbans. Pet food that spills or is otherwise considered unfit for feeding pets may beintentionally or inadvertently fed to livestock on the farm. Moreover, these materialsaresometimessentback through the renderingprocessasaby-productofpet foodmanufacturing.
Catering(table)wastealsooftencontainsanimal-derivedproteins(suchasbeef)thatmaybeotherwiseprohibitedforlivestockspecies.However,becauseallcateringwastewas at one time deemed fit for human consumption, it should pose no risk if otheradequateTSEcontrolmeasuresareinplace.Forexample,eventhoughthefeedingofruminantproteintoruminantsisprohibitedbyallfeedbans,ifSRMsareexcludedfromthe human food chain and appropriate slaughter methods are used, then beef meat
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protein use in
livestock feeding
shouldposeanegligiblerisk.Thisproductismostimportantinthecontextofthespreadofotheranimaldiseases,suchasfootandmouthdisease(FMD).
Milkreplacers,tallow,andotherfat-basedproductshavebeensuspectedtoberiskfactorsfortheintroductionofBSEintosomecountries,althoughthishasneverbeenproven.FatitselfisnotconsideredtobeSRM.RenderedtallowisconsiderednegligibleriskifSRMisexcludedfromtherenderingprocess,andifrestrictionsonthecontentofproteinsandothersolidsinthefatsandotherprocessingguidelinesaimedtoreducetheriskofBSEinfectivityarecompliedwith.Milk-basedproductsareconsideredtobeofnegligibleriskOIE,2005).
Poultry litter includes excreta, bedding, unconsumed feed, and feathers, and hasbeenusedasasourceoffreenitrogenandofproteinpeptidesinlivestockfeeds,pri-marilyasaninexpensivemethodofdisposal.AlthoughpoultryspeciesarenotknowntobesusceptibletoTSEs,ithasbeensuggestedthatprionspotentiallypresentinpoultryfeedsmightpassthroughthedigestivetractandbepresentinthelitter.Thiscouldposeaverysmallriskifthelitterwasthenfedtoruminants.
2.�. Impact of the BSE feed bans on animal nutritionInEurope,andsubsequentlyinothercountries,theMBMbanshaveresultedinaneedtofindalternativeproteinsourcesforlivestockfeed.AccordingtoAbeletal.(2002),foralltheprotein(andaminoacids)previouslysuppliedby2.3milliontonnes(MT)ofMBMtobereplacedintheEU,about2.3MTsoyabeanmeal,4.6MTpeas,3.9MTbeansor2.8MTlupin(e)swouldbeneeded.However,theseauthorsalsosuggestthatplantmealsare inferiortoanimalmealswithregardtovariousothercomponents,andthatplantmealsmaycontainanti-nutritive factors thatcannegativelyaffect feed intakeand/ornutrient availability. In some countries, differences in costs of the different sourcesmustalsobeconsidered.However,moreaccuratelivestockfeedingsystems(e.g.phasefeeding)withadjusteddietaryaminoacidconcentrationshaverecentlybeendevelopedthatallowforproteinstoremainatlevelssimilartothatcontributedbyMBM.Consider-ingthis,MBMbanscouldberegardedaminorprobleminsomecountriesintermsofensuringaminoacidsupply.
Anadditionalconsequenceofthefeedban,atleastintheEU(whichhashadatotalfeedbansince2001), isanoverall reduction inphosphorous (P) supply,which isnotcompensatedbytheuseofplantmeals.Anadditional100000tonnesofinorganicPforfeedisnowneededintheEU(Abeletal.,2002).Atpresent,thisissuppliedbyincreasedminingofrockphosphates.Useofmicrobialphytaseenzyme(whichincreasestheavail-abilityofPfromplantmaterials)inlivestockrationscouldhelptosolvethisprobleminthefuture.
3. SUmmARy OF TSE-RELEvANT CONCEpTS• Fromanutritionalandeconomicstandpoint,animalby-productswereconsidered
agoodandplentifulsourceofproteinforlivestockfeeds.• BecausetotheemergenceofBSE,appropriatealternateproteinsourcesforlive-
stockfeedshavehadtobefound,whichisnutritionallymorechallengingforpigandpoultryfeedsthanitisforruminantfeeds.
• TherisksofMBMfromsomeregionsmadefromcertainhigh-riskmaterialsarewell documented, but alternative protein sources (including some that are notprohibitedinfeeds)mayalsostillposesomeBSErisk.
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• Someproductsthatposenoinherentriskmaystillcontaininfectivityduetocrosscontaminationduringproduction.
4. REFERENCESAbel Hj, Rodehutscord m, Friedt w, wenk C, Flachowsky G, Ahlgrimm H-J, Johnke B, kühl
R, Breves G. 2002. The ban of by-products from terrestrial animals in livestock feeding:
consequences for feeding, plant production, and alternative disposal ways. Proc Soc NutrPhysiol 11,201-229
FAO.2004.AnimalFeedResourcesInformationSystem(AFRIS).http://www.fao.org/ag/AGA/AGAP/
FRG/AFRIS/index_en.htm
matthews D, Cooke BC.2003.Thepotentialfortransmissiblespongiformencephalopathiesinnon-
ruminantlivestockandfish,RevscitechnOffintEpiz,22(1),283-296
miller EL.2004.Proteinnutritionrequirementsoffarmedlivestockanddietarysupply.In:Proteinsourcesfortheanimalfeed industry.ExpertConsultationandWorkshop.Bangkok,29April-3May 2002. http://www.fao.org/documents/show_cdr.asp?url_file=/docrep/007/y5019e/y5019e00.
htm
OIE (world Organization for Animal Health).2005.Bovinespongiformencephalopathy.TerrestrialAnimalHealthCode,Chapter2.3.13.http://www.oie.int/eng/normes/MCode/en_chapitre_2.3.13.
htm
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Inactivation of
TSE agents
inactivation of tse agents
1. GENERAL CONCEpTSAlthoughthereremainquestionsaboutthecharacteristicsandpathophysiologyoftheprionsthatarethediseaseagentsofTSEs,theirinfectivityisknowntobehighlyresist-ant tomany formsof inactivation.This resistance to inactivation is important,as thepresenceofinfectiveagentinrenderedanimalby-productssubsequentlyfedtoanimalshasbeentheprimaryfactorintheexpansionofBSEintheworld.Therefore,controlofboth theprocessingparameters for renderingofanimalby-productsand thesubse-quentuseoftheprocessedproductsinanimalfeedarecrucialcomponentsofanyTSEcontrolprogram.
Moreover,manyexamplesof inadvertent transmissionofotherTSEs throughcon-taminatedmaterialsexist.SporadicCreuzfeldt-Jakobdisease(CJD)isdocumentedtohavebeentransmittedfrompatienttopatientthroughtheuseofinadequatelydecon-taminatedneurosurgicalequipment(Bernoullietal.,1997).Scrapiehasbeentransmit-ted to sheep and goats through the survival of this agent in formol-treated vaccines(Agrimietal.,1999).
Foreffectivedevelopmentandimplementationofcontrols,somefundamentalfactsaboutTSEagentinactivationmustbetakeninaccount.
2. INACTIvATION pROCEDURES Rendering isusedtomanufacturemeatandbonemeal (MBM)fromanimalby-prod-uctsprimarily,butnotexclusively,forinclusioninanimalfeed.Therenderingprocessisdescribedinthe“Renderingofanimalby-products”chapterinthiscoursemanual.However,BSEinfectivityhasbeendocumentedtoremaininmaterialafterbeingsub-jectedtothecommonrenderingprocessesusedworldwide(TaylorandWoodgate,2003).It isthissituationthat iscreditedwiththeexpansionoftheBSEoutbreakthroughoutEuropeandtheworld.
Worldwide,oneormoreofthefollowinginactivationprocedureshavegenerallybeenusedformaterialpotentiallycontainingprions:
• batchautoclavingat134-138ºCfor18minutes(Europe);• exposure tosodiumhypochloritesolution (20000ppm)available inchlorine for
onehour(Europe);• exposureto1Msodiumhydroxideforonehour(USA);• continuousautoclavingat132ºCforonehour(USA).
Some of these methods have been incorporated into formal recommendations onreducingTSEinfectivity(OIE,2005;EU,2002),althoughthereisstillsomequestionasto their actual effectiveness in certain situations. Because different research studiesofinactivationandinfectivityusedifferentTSEagentsandstrainsofagents,thereareoftendiscrepanciesbetweenstudyresults,andthereforeinterpretationsmustbemadecarefully.
Inactivationproceduresrelyingsolelyonheatandpressureareusedonalargescaleintherenderingindustry,whereaschemicalinactivationmostoftenisappliedtomate-
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rialfromdiagnosticlaboratoriesorfromresearch.Inmanylaboratoriesacombinationofbothproceduresisapplied.Thesetwoproceduresarebrieflydiscussedbelow.
2.1. Heat/pressure inactivationAlthoughheatiscommonlyusedinanattempttoinactivateprions,ithasbeenreportedthatdryheatmaynotbeveryeffective.Inonestudy,dryheatattemperaturesupto180ºCforonehourdidnotinactivatetheME7strainofscrapieagentandsomeinfectivityremainedevenafterexposuretodryheatat160ºCfor24hours.However,aone-hourtreatment of dry heat at 200 ºC was effective with certain TSE strains (Taylor et al.,1996)
InmorerecentstudiescarriedoutbyBrownetal.(2000)itwasreportedthattracesofscrapieinfectivitycouldstillbedetectedafterbraintissueinfectedwith263K(anotherstrainofscrapieagent)hadbeenexposedtodryheatat600ºCfor15minutes.Ithasbeen speculated that this is due to the persistence of an inorganic skeleton of theinfectiveprionevenafterheatingto600ºC,andthatthisskeletonmightstillbeabletotriggertheconversionofnormalcellularprionprotein(PrPc)intotheinfectiveprionform(PrPsc).Completeburningofmaterialattemperatureabove1000ºCisgenerallyeffectiveforcompleteinactivation.
However,whenmoistureisaddedtheeffectivenessofheatinactivationimproves.IthasbeendemonstratedthatsmallamountsofTSEagentcanbe inactivated inbatchrenderingsystemswhenexposedto134ºCandhighmoisturecontentfor14-18min-utes (Kimberlim et al., 1983). However, further studies with larger samples showedthattheinactivationmightnotbecomplete.IthasbeensuggestedthatlargersamplesmorerealisticallyrepresenttheactualvolumeofpotentiallyTSE-infectedtissuethatisdisposedofbyslaughterhouses(aswellasbyhumanorveterinaryhealthcaresystemsandotheragriculturalsystems)andthatsubsequentlyrequiresinactivation.Also,par-tialdryingofsmallamountsofinfectedtissueontoglassormetalsurfaceswithintheautoclavingorrenderingsystemshouldbetakenintoaccountwhendefiningeffectivestandards for inactivation of TSE agents by heat, as these materials might harbouradditionalinfectivity.
Otherexperimentshaveinvestigatedtheinactivationofdifferentscrapiestrains,dif-ferentamountsofinfectivity,anddifferentexposuredurationsattemperaturesbetween134and138ºC(TaylorandWoodgate,2003).Thesedatasuggestthatthethermostabilityofsomescrapieagentsvarieswiththeheatingprocedure,andinactivationisdependentonboth temperatureandholding time.Therefore,simply increasing the temperatureandkeepingtheholdingtimeconstantwillnotnecessarilylinearlyimprovetheinactiva-tion.Consequently,bothparametersshouldbeanalysedtogether.
In summary, most experimental evidence confirms that application of the conven-tionalrenderingparametersof133ºCat3barsofpressurefor20minutesreducestheinfectivityofaTSEagent in renderedmaterialbyanaverageof three logs.However,otheraspectsoftherenderingprocessareimportanttooptimizetheinactivation.Parti-clesizeshouldbenogreaterthan50mm(OIE,2005)andabatchratherthancontinuousprocessshouldbeused.Finally,complementarymeasures (e.g.anSRMban)shouldbeinplacetoexcludehighconcentrationsofTSEinfectivityfrominitiallyenteringthesystem(HeimandKihm,2003).
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2.2. Chemical inactivationExperimentsinvestigatingtheinactivationofvariousTSEagentsusingchemicalshavealsobeenpublished. Inonestudy, twoyearsofexposureof theBSEagent to formolsalinehadlittleeffectonreducinginfectivity(Fraseretal.,1992).TSEagentsalsoresistinactivationbyformalinandotheraldehydes,althoughBSEinfectivitywasinactivatedby30minutesofexposuretoasolutionofsodiumhypochlorite(NaOCl)containing16500ppmofavailablechlorine(Tayloretal.,1994).
StudieswithBSE-infectedbovinebrainandscrapie-infectedrodentbrainshowedthattreatmentwith1or2Msodiumhydroxide(NaOH)foruptotwohoursdidnotcompletelyinactivatetheseagents,andpermittedthepersistenceofuptofourlogsof infectivity(Tayloretal.,1994).Thedetectionofresidualscrapieinfectivityaftertreatmentwith1MNaOHforonehourandthesurvivalofCJDinfectivityafterexposureto1or2MNaOHhavealsobeenreported(ErnstandRace,1993).
EffectiveinactivationofTSEagentscanalsobeachievedbycombiningtheautoclavingprocedureandtheexposuretoNaOH.Ithasbeenshownthatthe22Astrainofscrapieisinactivatedbyautoclavingat121ºCfor30mininthepresenceof2MNaOH(Tayloretal., 1997).Therearepracticalproblemswith thisprocedure,suchas thepotentialexposureofoperatorstosplashingwithNaOH,andthepotentialdeleteriouseffectontheautoclaveandthematerialswithin(e.g.surgicalinstruments).
Although these chemical methods are not practical for inactivation of TSE agentsin large volumesofanimalby-products, theycouldbeapplied todecontamination inlaboratorysituationsorwhensurgical instrumentsmustbesterilizedprior to reuse.This is of considerable importance, since major concerns exist in human medicineabout inactivation of TSE agents in instruments used in general surgery, as well asneurosurgery.
3. FUTURE DEvELOpmENT OF INACTIvATION IN RENDERING It is widely accepted that the conventional techniques used for rendering animal by-productsconsiderablyreduce infectivity,butdonotcompletely inactivateTSEagents.Therefore,itwillbemostimportantinthefuturetodefinetheparametersforhandling,storageanduseofrenderedmaterial.Tooptimizeinactivation,high-riskmaterialmustbeexcludedfromanyrenderingprocesswheretheproductscouldbeincludedinanimalfeed.
Asdescribedabove for inactivationgenerally, thespecific inactivationeffectduringrenderingisdefinedbymultiplefactorssuchastemperature,moisturecontent,particlesize,TSEstrain,chemicalagents,bindingsurfacesandtime.Resultsunderlaboratoryconditionshavetobeadaptedtorenderingonalargescale.Becausethereisnogener-allyaccepted inactivationcurve forall typesof inactivation, it isat leastquestionableto apply results from one rendering system to another without further investigation.Theseissuesareexploredfurtherinthe“Renderingofanimalby-products”chapterinthiscoursemanual.
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4. REFERENCESAgrimi U, Cardone F, pocchiari m, Caramelli m. 1999. Epidemic of transmissible spongiform
encephalopathyinsheepandgoatsinItaly.Lancet353,560-561
Bernoulli C, Siegrief J, Baumgartner G, Regli F, Rabinowicz T, Gajdusek DC, Gibbs CJ Jr.1977.
Dangerofaccidentalperson toperson transmissionofCreutzfeldt-Jakobdiseasebysurgery.
Lancet1(8009)478-479Brown p, Rau EH, Johnson Bk, Bacote AE, Gibbs CJ Jr, Gajdusek DC.2000.Newstudiesonthe
heat resistance of hamster-adapted scrapie agent; threshold survival after ashing at 600C
suggestsaninorganictemplateofreplication.PNAS97,3418-3421
Ernst DR, Race RE. 1993. Comparative analysis of scrapie agent inactivation. J Virol. Methods41,193-202
EU (European Union). 2002.Regulation (EC)No1774/2002 layingdownhealthrulesconcerning
animalby-productsnotintendedforhumanconsumption.http://europa.eu.int/eur-lex/pri/en/oj/
dat/2002/l_273/l_27320021010en00010095.pdf
Fraser H, Bruce mE, Chree A, mcConnel I, wells GA. 1992.Transmissionofbovinespongiform
encephalopathyandscrapietomice.JGenVirol173,1891-1897
Heim D, kihm U. 2003. Risk Management of transmissible spongiform encephalopathies in
Europe.RevscitechOffIntEpiz22(1),179-199
kimberlin RH, walker CA, millson GC, Taylor Dm, Robertson pA, Tomlinson AH, Dickinson AG. 1983. Disinfection studies with two strains of mouse-passaged scrapie agent. Guidelines for
Creutzfeldt-Jakobandrelatedagents.JNeurolsci59,355-369
OIE (world Organization for Animal Health). 2005.Procedures for the reductionof infectivityof
transmissible spongiform encephalopathy agents. Terrestrial Animal Health Code, Appendix3.6.3.http://www.oie.int/eng/normes/MCode/en_chapitre_3.6.3.htm
Taylor Dm, Fraser H, mcConnell I, Brown DA, Brown kL, Lamza kA, Smith GR. 1994.
Decontamination studies with the agents of bovine spongiform encepholopathy and scrapie.
ArchVirol139,313-326
Taylor Dm, mcConnell I, Fernie k.1996.TheeffectofdryheatonME7strainofscrapieagent.JGenVirol.77,3161-3164
Taylor Dm et al. 1997. Inactivation of the 22A strain of scrapie agent by autoclaving in sodium
hydroxide.VetMicrobiol58,87-91
Taylor m, woodgate SL.2003.Renderingpracticesand inactivationof transmissiblespongiform
encephalopathyagents.RevscitechOffIntEpiz22(1),297-310
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Rendering
of animal
by-products
rendering of animal by-Products
1. GENERAL CONCEpTSWhenconsideringthemeatindustry,itisoftenforgottenthatasubstantialproportionofeachslaughteredanimaldoesnotenterthehumanfoodchain.Duringthenormalslaughterandprocessingofanimals,33-43%oftheliveanimalweightisremovedanddiscardedas inediblewaste (by-products). Theactualpercentagedependsmostlyonthespecies,andishighestforruminants,moderateforswine,andlowestforpoultry.Moreover,italsodependsonthecountry,withindustrializedcountriesusingthelow-est percentage of each animal for human consumption. These discarded animal by-products(e.g.fattrim,meattrim,viscera,bone,blood,feathersinpoultry)mustbesafe-lydisposedof,astheymayrepresentariskforhumanandanimalhealth.Inaddition,someanimalsdieonthefarm,havetobeeuthanizedforvariousreasons,orarejudgedunfitforhumanconsumption.Thesafedisposaloftheseanimals(generallycalledfallenstockordowneranimals)isanimportantissuewithregardtoTSEcontrol.
Inmanycountries,animalby-productsarecollectedandthenprocessedbytheren-deringindustryintohigh-qualityfats(tallow)andproteins(meatandbonemeal/MBMandotherproteinmeals).Historically,MBMhasbeenanexcellentsourceofsupplemen-taryproteinduetoitswell-balancedaminoacidprofile,asdescribedinthe“Proteinuseinlivestockfeeding”chapterinthiscoursemanual.Inthepast,renderersintheformer15countriesof theEUprocessedabout16million tonnesofanimalby-productsperyear,whilethoseinNorthAmericaprocessednearly25milliontonnesperyear.Argen-tina,Australia,BrazilandNewZealandcollectivelyprocessedanother10milliontonnesperyearandthe increasingproduction inAsiarepresentsbetween10and14milliontonnesperyear.Fromaneconomicpointofview,therenderingindustryhastradition-allybeenquiteprofitable,astherenderedproductsweresoldforusebytheanimalfeedandoleochemicalindustriesaroundtheworld.Thetotalvalueofthefinishedrenderedproductsworldwide,beforetheimplementationofthecurrentTSE-relatedfeedbans,wasestimatedtobebetweenUS$6andUS$8billionperyear(Hamilton,2002).
2. THE RENDERING pROCESS Theterm“renderingofanimalby-products” isusedtodescribemanydifferentproc-esses applied to raw animal by-products. In this course manual, rendering refers tothepressureheatingofanimalby-productstomakeproductsforfurtheruse,includinguse inanimalfeeding.Renderingcantakeplaceaspartof theactivitiesofaspecificslaughterhouseorataseparateplantwhereanimalby-productsfrommultiplesourcesarecollected.
After arrival and collection at the rendering plant, animal by-products are movedontoaconveyerbelt,passedthroughametaldetector,andtransportedtoacrusher.There,therawmaterialiscrushedtoreduceparticlesize.Thenthematerialispressuresterilizedinthesterilizer.Aftersterilizationaviscousmassremains,whichispassedthroughafiltertoseparateliquidsandsolids.Inanenergy-intensiveprocessstep,thesolidparticlesarethendriedandground,yieldingacoarse-grainedpowderwithahigh
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animalproteincontent(animalmeal).Theliquidphasecontainsthefatfraction.Usingcentrifugalforcesorpresses,thefatsareseparatedfromtheotherliquidproductsandcanbefurtherprocessed.
Inthisprocess,temperature,pressure,andtimeareallimportant.Theheatingandpressuremustbeapplied in thesterilizer for theentire time, i.e. thetime it takestoreachthecorrecttemperatureandpressureshouldnotbeincludedintheprocessingduration. Also, the system used for the flow of raw material being processed in thesterilizer is important.Systemswherethematerialsareprocessed inbatches (batchsystems) are optimal for achieving the appropriate conditions, whereas continuous(i.e.flow-through)systemsmaynotbe.Inaddition,themaximalsizeoftheparticleisimportant,aspenetrationandthereforeinactivationimproveswithsmallerparticlesize.Therefore,mostcountriesrequireareductionoftheparticlesizebeforeheattreatmenttolessthan50millimetres(OIE,2005).
Therenderingparameterscanvaryaccordingtolegislativerequirements.InEurope,therenderingparametersformostanimalby-products(includingallBSEriskmaterial)requireaminimumheatingattheOIE-recommendedparametersof133°Cat3barsofpressurefor20minutes(OIE,2005).Lessstringentparametersonlycanbeappliedtocertaincategoriesofmaterialsthatrepresentminorrisktohumanandanimalhealth(EU,2002).
Worldwide,theminimumparametersfortheprocessingofanimalby-productsvarysubstantially,andaregenerallysubstantiallylowerthanrecommendedbytheOIE.Heatrequirementsmaybebelow100°Candpressuremayonlyberequiredincertainsitua-tions.Often,particlesizeisnotcontrolled,andcontinuoussystemsareused.
3. GOALS OF THE RENDERING pROCESS Irrespectiveoftheultimateusemadeoftherenderedproducts,twogoalsofrenderingareto:
• reduce the volume of animal by-products through the separation of the waterfractionfromtheremainingmaterial;
• minimizetheanimalandpublichealthriskfrompossiblepathogensthroughthepressuresterilizationprocess.
Unprocessed animal by-products contain approximately 60-65% water, as deter-minedby therelativeamountofmeat (higherwatercontent)andbones (lowerwatercontent).Theheatusedintherenderingprocessremovesmostofthemoisture,therebyreducingthevolume,whichisimportantwhenconsideringdisposal.Theindividualper-centagesofthefinalanimalmealandfatfractionsvaryaccordingtotheproportionofmeatandboneintherawanimalby-products,butthecombinedfinalweightisnormallyapproximately35%oftherawanimalby-productweight.Thefinalvolumeoftheanimalmealfractionisapproximately23%andthefatfractionapproximately12%oftherawanimal by-product volume. Globally, the rendering process reduces the total animalby-productvolumefrom60milliontonnesofrawmaterialtoabout8milliontonnesofanimalproteinsand8.2milliontonnesofrenderedfats(Hamilton,2002).
Theheatoftherenderingprocessalsosterilizestheby-products,astheprocessingtemperaturesareusuallymorethansufficienttokillbacteria,virusesandmanyothermicroorganisms.Arecentstudyshowedthatrenderingat133°Cat3barsofpressurefor 20 minutes eliminated Clostridium Spp., Listeria Spp., Campylobacter Spp.andSalmonellaSpp.inrawanimaltissues(Troutetal.,2001).Suchhightemperaturesare
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Rendering
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by-products
alsoeffectiveinkillingtheanthraxbacterium(Clostridiumanthracii)anddestroyingthefootandmouthdiseasevirus.However,renderingdoesnotcompletelydestroytheprioncausingBSE(seethe“InactivationofTSEagents”chapterinthiscoursemanual),whichhasledtothevariousbansonincludingrenderedanimalproteininlivestockfeedsinEuropeandinmanyothercountries(asdiscussedthroughoutthiscoursemanual).
4. OTHER OpTIONS FOR ANImAL By-pRODUCT DISpOSALWith implementation of the MBM bans in livestock feed, the disposal of animal by-products,eitherassuchorasrenderedmeals,becomesanextremelylargeproblemforallcountries.Whatultimatelyhappenstothesematerialsandproductswilldependonwhatrawmaterialwasusedaswellastheregulationsofthecountry.
Some alternatives currently being applied or considered are incineration, co-incineration(e.g.inthecementindustry,inwasteincineration,orinfertilizerprocess-ing),burial,disposal in landfills,use inbiogasproductionorcomposting.MostEuro-pean countries are using some form of incineration. However, incineration requiresinitialrendering(primarilytoreducethevolume)andstorageoftherenderedmaterialbeforeincineration.Directincinerationofrawmaterialispossible,butcannotbeusedon a large scale. Recent estimates by the European Fat Processors and RenderersAssociationgivetheannualincinerationcapacityintheEUas2.5milliontonnes,whilethequantitytobeincineratedisputat3.6milliontonnes(EU,2001).
Abeletal.(2002)alsonotetheproductionofgreenhouseandnoxiousgasesproducedby incineration. They calculate that combustion of one kilogram (kg) of MBM causesreleaseofabout1.4kgofcombinedcarbondioxide(CO2),carbonmonoxide(CO),andsome further trace gases including nitrous oxide (N2O) and sulphur dioxide (SO2). Ofthese, N2O is the most dangerous because its global warming potential has beenestimatedat310timesthatofCO2andbecauseofitsozonedepletingpotentialinthestratosphere.
Composting and other biological methods of raw material disposal do not achievethehightemperaturesnecessarytomakethematerialmicrobiologicallysafewithoutpriorheating.Inaddition,burial,disposalinlandfills,andstorageofdrymaterialposeunacceptableenvironmental risksas theyaresubject to incursionofbirdsandotheranimals,whichmaythenspreaddiseaseagentsoutintotheenvironment.
Regardlessofmethod,thecostsofdisposalmaybeveryhigh.Theyarecertainlyhigh-erthanbeforeTSE-relatedfeedbanswereimposed,whentherenderingindustrygen-erallypaidtopurchasetherawanimalby-productsfromfarmersandslaughterhousesandstillproducedproductsataprofit.ThedataofAbeletal.(2002)showthatthetotalcostsofthealternativeuseordisposalof3.6milliontonnesofMBMvariesfrom€1.0-1.8billion.Onaverage,everykgofMBMnotusedinlivestockfeedincursacostofabout€0.32,ornearlytwicethe1999supplypriceofMBM.Expresseddifferently,foreverykgofMBMnotusedinlivestockfeed,thereisanoveralleconomiclossofabout€0.14.
�. ANImAL By-pRODUCT LEGISLATION IN THE EUROpEAN UNIONAregulationlayingdownrulesconcerninganimalby-productsnotintendedforhumanconsumptionwasadoptedbytheEUinOctober2002,andappliedon1May2003(EU,2002).Inparticular,theregulation(referredtohereasRegulation1774/2002)introducesstringent conditions throughout the food and feed chains including safe collection,transport,storage,handling,processing,useanddisposalofanimalby-products.
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Asageneralprinciple,Regulation1774/2002describesarisk-basedcategorizationsystemforanimalby-products,andtheirpossibleuses.Threecategoriesaredefined.
• Category 1 Regulation1774/2002requires thecompletedisposal,by incinerationor landfill
afterappropriateheattreatment(133°C/3bars/20minutes),ofCategory1mate-rials.TherawmaterialofCategory1isdefinedasanimalby-productspresentingthe highest risk for diseases such as BSE or other TSEs (e.g. scrapie). It alsoincludesfallenstockfromruminantsandfromanimalsnotintendedforhumanconsumption(e.g.companionanimals,researchanimals).
• Category 2 Category 2 material can be used in the same way as animal by-products of
Category 1. In addition, it may be recycled for technical uses after proper heattreatment (e.g.biogas,composting,oleochemicalproducts).Theuseforanimalfeedingisprohibited.TherawmaterialofCategory2includesanimalby-productsthathavebeenrejectedbyante/postmortem inspection in theslaughterhouse.TheyalsopresentariskofcontaminationwithanimaldiseasesotherthanBSE.
• Category 3 Regulation 1774/2002 states that only Category 3 materials may be used in the
productionofanimalfeeds(includingpetfoods)followingappropriatetreatmentinapprovedprocessingplants.TherawmaterialofCategory3isdefinedasanimalby-products derived from healthy animals slaughtered for human consumption.
Thus, under Regulation 1774/2002, only materials derived from animals declaredfitforhumanconsumptionfollowingveterinaryinspectionmaypotentiallybeusedforthe production of livestock feeds. The regulationalso requires the exclusion of deadanimalsandothercondemnedmaterialsfromthefeedchain,thecompleteseparationduring collection, transport, storage, handling and processing of animal by-productsnotintendedforanimalfeedorhumanfood,andthecompleteseparationofrenderingplantsdedicatedtofeedproductionfromrenderingplantsprocessinganimalby-prod-uctsdestinedfordestruction(i.e.bycategoryofrawmaterialprocessed).
Italsosetsoutclearrulesonwhatcanandmustbedonewiththeexcludedanimalmaterials,includingimposingastrictidentificationandtraceabilitysystemandrequir-ingcertainproductssuchasMBMandfatsdestinedfordestructiontobepermanentlymarkedtoavoidpossiblefraudandriskofdiversionofunauthorizedproductsintofoodand feed.ThecontrolofmovementsofSRMbyarecord-keepingsystemandaccom-panyingdocumentsorhealthcertificates isalso required.Regulation1774/2002alsoprohibits any intra-species recycling of processed proteins (feeding material derivedfromaspeciesbacktothesamespecies).
However, Regulation 1��4/2002 does not in any way change or affect the current EU total ban on the feeding of mBm to farmed animals, which is a separate issue and remains in force without any termination date set.Regulation1774/2002onlyestab-lishesclearsafetyrulesfortheproductionofMBMincaseit iseverreauthorizedforinclusioninfeedforcertainnon-ruminantspecies,e.g.poultryorpigs.
WiththeadoptionofRegulation1774/2002,theenvironmentalandeconomicreper-cussionsof thefeedbancanpotentiallybereduced inthefuture,asonly twomilliontonnes of material derived from animals unfit for human consumption (compared tothe16million tonnesofanimalby-products incaseofa totalban)wouldneed tobedisposedof.
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Rendering
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�. THE FUTURE USE OF mEAT AND BONE mEALItispossiblethat,inthefuture,MBMcouldagainbeusedinfeedforfarmedanimalsin countries where it is presently banned (including countries in Europe) if appropri-atelegislationandcontrolsareimplementedandenforced.However,itsusewillmostprobablyalwaysberestrictedtonon-ruminantanimals.IfSRMisremoved,fallenstockareexcluded,andtheprocessensuresheattreatmentat133°Cat3barpressurefor20minutesitisassumedthattheriskofinfectivityofaTSEagentthatmightbepresentismarkedlyreduced.Inaddition,betterclassificationandseparationofdifferentmate-rials would further reduce the risk from the rendered products. However, caution isrequiredasthisstepmustonlybetakenifthesemeasurescouldbeeffectivelyimple-mented.
Irrespectiveofanyscientificjustifications,however,theBSEoutbreakhasseriouslyaffectedthepublicperception,atleastinEurope,regardingtherenderingindustry,thefeedingofanimalproteinstonaturallyherbivorousanimals,andthefeedingofproteinsderivedfromonespeciesbacktothesamespecies(whichmaybeseenascannibal-ism).TheseperceptionswillundoubtedlyinfluencetheacceptanceoftheuseofMBMoranimal-derivedproductsinanimalfeedsinthefuture.
�. SUmmARy OF TSE-RELEvANT CONCEpTS• Renderingprocessesandparametersvarysubstantiallyamongcountriesthrough-
outtheworld.• AppropriaterenderingcanreduceTSEinfectivityinanimalby-products,although
infectivityisnotentirelyinactivated.• Incinerationbysomemethodiscurrentlythemosteffectivemethodofdisposalof
TSEriskmaterial(rawandprocessedanimalby-products).• Although there is limitedcapacity foralternatedisposalof the largeamountof
rendered material that is now prohibited in feed, it must be assured that thismaterial isproperlydisposedofsothatitdoesnotillegallyre-enterthefoodorfeedchain.
• Separationofby-productsbyriskcategorycouldeventuallyallowtheuseofsomeanimalproductsinlivestockfeeds.
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�. REFERENCESAbel HJ, Rodehutscord m, Friedt w, wenk C, Flachowsky G, Ahlgrimm H-J, Johnke B, kühl
R Breves G. 2002. The ban of by-products from terrestrial animals in livestock feeding:
consequences for feeding, plant production, and alternative disposal ways. Proc Soc NutrPhysiol11,201-229
EC (European Commission). 2001.Commissionservicespaperon theprocessing,disposaland
usesofanimalby-productsinMemberStates.http://europa.eu.int/rapid/pressReleasesAction.
do?reference=MEMO/01/378&format=HTML&aged=0&language=EN&guiLanguage=en - file.
tmp_Foot_5
EU (European Union).2002.Regulation (EC)No1774/2002 layingdownhealthrulesconcerning
animal by-products not intended for human consumption. http://europa.eu.int/eur-lex/pri/en/
oj/dat/2002/l_273/l_27320021010en00010095.pdf
Hamilton CR.2002.Realandperceivedissuesinvolvinganimalproteins.Proceedingsofanexpert
consultationonalternativeproteinsourcesfortheanimalfeedindustry.FAO,Rome.
OIE (world Organization for Animal Health). 2005.Procedures for the reductionof infectivityof
transmissible spongiform encephalopathy agents. Terrestrial Animal Health Code, Appendix3.6.3.http://www.oie.int/eng/normes/MCode/en_chapitre_3.6.3.htm
Trout HF, Schaeffer D, kakoma I, pearl, G. 2001. Directors Digest No. 312. Fats and Proteins
ResearchFoundation.
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mANUFACTURING OF COmpOUND FEEDS FOR LIvESTOCk1
1. GENERAL CONCEpTSAlthoughproductionofcompoundfeedsforlivestockhaslevelledofforisdeclininginmanypartsofEuropeandNorthAmerica(Figures1aandb),itstillmaintainsanimpor-tanteconomicposition.ForexampleinEurope,compoundfeedproductionranksthirdaftermeatanddairyproduction,accountingfor7%ofthetotalsalesofCHF750billioninthissector.Feedmanufacturingwilllikelymaintainthisroleintheforeseeablefuture,althoughgrowthmayshiftgeographically.
Compoundfeedsaremanufacturedprimarilyfromorganiccompoundsofvegetableoranimalorigin.Thesmallinorganicpercentageisprimarilyofmineralorigin.Becauseofthehistoricalimportanceofincludingingredientsofanimalorigin,manufacturingofcompound feeds throughout theworldhasbeenaffectedby theappearanceofTSEs.Inmanycountries,feedproductshavehadtoundergoreformulationtocompensateforprohibited materials, and stricter controls of contamination and cross contaminationhavebeenimplementedinfeed-producingplants.
Inthischapter,amodernfeedmanufacturingprocess,usingthemosttechnologicallyadvancedequipmentpossible,isdescribed.ThischapterdoesnotcontainasummaryofTSE-relevantconcepts.Otheraspectsoffeedproductionarepresentedinotherchap-tersofthiscoursemanual.Forexample,aspectsofqualityassurancefortheprocessingstepsdescribedherearepresentedinthe“Qualityassuranceinfeed-producingplants”chapter.
2. STRUCTURE OF A FEED pRODUCTION pLANTA feedproductionplantcangenerallybedivided into themainprocessingareasandsecondaryprocessingareas,andservicesand infrastructure.Theservicesand infra-structurewillnotbedescribedhere,astheydonotdirectlyrelatetothequalityorsafetyofthefeedsproduced.
Mainprocessingareas:• Reception(intake)andcleaning• Proportioningandweighing• Grinding• Mixingandhomogenizing• Pelleting• Finishedproducts
1 ThemajorityofinformationwithinthischapterisextracteddirectlyoradaptedfrommaterialscopyrightedbytheSwissInstituteofFeedTechnology(SFT),underabilateralagreementwithSAFOSO(Nef,2002).TheSFTreserves all rights to this material and the objects described herein. This information must not be furtherreproducedorduplicated,eitherwhollyor inpart,norbemadeaccessible,eitherwhollyor inpart, to thirdpartiesinanyformwhatever,norbeusedforanypurposeotherthanthatforwhichithasbeengiventotherecipient.
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Secondaryprocessingareas:• Crushingofgrain• Hullingofgrain• Flaking• Extrusion• Expansion• Heattreatment
Servicesandinfrastructure• Exhaustsystems• Compressedairsupply• Steamsupply• Watersupply• Electricinstallationandcontrolsystem
FigUre 1a
world feed production by feed type, 1��4
Source:adaptedfromNef(2002).
Compound feeds:530 million tons
Home mixing: 350 million tons
Single ingredients:220 million tons
FigUre 1b
percent of world feed production by region, 1��4
Source:adaptedfromNef(2002).
North America24%
Latin America11%
Asia & Oceania26%
Eastern Europe11%
Western Europe24%
Middle East & Africa
4%
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3. FEED pRODUCTION pROCESSES 3.1. Intake of raw ingredientsTherawingredientstobeprocessedmayarriveatthefeedplantviaship,rail,orroad.Weight checks are usually performed at weighing bridges in the case of rail or roadvehicles,and/orbyintakescalesinthevariousin-plantconveyingsystems.
Grainisnormallysuppliedinbulk,andmealsormeal-typeingredients maybesup-pliedinbulkorinbags.Feedplantswithalowcapacitycanusethesamelineformealreceptionas forgrainreception.Largecapacity feedplants,ontheotherhand,musthaveseparatereceivingsectionsandconveyinglinestoaccommodatethelargevolumeofgrainarrivingperday.
Mineralsaswellaspremixesmaybesuppliedinplasticorpaperbags,tincans,ordrums, or they may be supplied by bulk trucks (tankers) with attached blowers. Forthistypeofsupply,apneumaticreceivinglinemustbeprovided.Premixesmayalsobeproducedin-house.
Bothfatandmolassesarenormallysuppliedinaheatedandliquidform.Theyaredischargedfromthebulktrucksintothestoragetanksdirectlybypumps.
The following machines and installations are used for receiving and conveying therawingredients:
• Shipunloadingsystems• Chainconveyors• Screwconveyors• Beltconveyors• Bucketelevators• Pneumaticconveyingsystems• Liquidspumps
3.2. Cleaning of raw ingredientsDependingontheiroriginandpreviousprocessing,rawingredientsmaybeheavilycon-taminatedandcontainforeignmatterthatmustberemoved.Asaresult,thecleaningsysteminafeedplanthastwofunctions:
• toseparateundesirableimpuritiessuchasstones,piecesofwood,strings,paper,straws,sand,andmetalparts;
• toprotectexpensive feedplantequipmentsuchasdischargers,hammermills,mixers,pelletmillsandothersagainstdamage.
Thefollowingequipmentmaybeusedforcleaningtherawingredients:• Drumsieves• Centrifugalsieves• Oscillatingsieves• Separators• De-stoners• Spoutmagnets• Cascademagnets• Drumtypemagnets
Dependingontheparticularmachine,theoutputfromthecleaningprocessincludestheacceptablematerial,aswellascourseimpurities,fineimpurities,anddust.
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3.3. Discharge and weighing of raw ingredientsBecauseoftheimportanceofofferingabalancedrationforaparticularlivestockspe-ciesorclass,compoundfeedproductsareusually formulatedandcontinuouslyopti-mizedbymeansofmoderncomputerprograms.Mostoftherawingredientsarestoredinbins.Theindividualpercentagesoftherawingredientsaredischargedfromthebinsusinga typeofdischargerappropriate to theparticularmaterial. Themostcommontypesareslidegatedischargers,rotarybindischargers,andscrewdischargers.
Afterdischarge,rawmaterialsarefedtotheallocatedscales.Inordertoguaranteethemostpreciseinputweighingpossible,themachineryiscapableofproportioningthematerialbyfastanddribbleflow.
Todeterminethenumberofbinsandthescalesize(s)needed,aproductformulalistisestablishedshowingtherequiredquantitiesoftheindividualingredients.Thescalesizeandthenumberofscalesareobtainedfromthelowestallowableingredientweightandthetotalweightperscaletobeweighedatonetime.Thelowestingredientweightthatcanbeweighedbyabatchscalemustbeatleast4%ofthescalecapacity.
3.4. Grinding Togetherwithmixingandpelleting,grindingtoreducetheparticlesizeofrawingredi-entsisakeyprocessincompoundfeedmanufacturing.About80%ofallrawingredi-entsusedfortheproductionofcompoundfeedrequiresizereduction.Sizereductionrankssecondinfeedplantenergyconsumption(afterpelleting),whichunderscorestheimportanceofcorrectsizingandoptimizedoperationofgrindingsystems.
Thepurposeofgrindingis:• toachievetherequiredmaterialfineness(texture)matchedtotheanimal'snutri-
tionalrequirementsanddigestivesystem;• toachieveuniformparticlesizeinordertoobtainahomogeneousproductduring
thesubsequentmixingoperation;• toachievethenecessaryfinenessinordertoobtainanacceptablepelletqualityif
thematerialissubsequentlypelleted.Abasicdistinction ismadebetweenpre-grindingandpost-grinding,andbothsys-
temsmayalsobedesignedforcirculationormulti-stagegrinding.Inpre-grindingsystems,alltheingredientsarefirstindividuallyground.Theadvan-
tagesofpre-grindingarethatgrindingisindependentofmixingandcanthereforebeefficientlyapplied,night-timegrindingatlowpowerratesispossible,andtheparticlesizedistributionof the individualmaterialscanbe varied.Thedisadvantagesare thehighcapitalcostofgrindingbinsandconveyorsforseparateingredients,thefactthatwithdifferentparticlesizedistributions there isdangerofsegregation (separationofrawingredients)inthefinishedfeedandthatmaterialscontainingchaffaredifficulttogrind.
Inpost-grindingsystems,alltheingredientsofamixarefirstproportioned,weighed,addedtogether,andthenground.Ifpossible,thefinesshouldbesiftedoutbeforegrind-ing.Theadvantagesofpost-grindingarethattheendparticlesizedistributioncanbecontrolledandtheproducttextureisuniform,hardtogrindmaterialsareeasiertogrindwhenmixedwithother ingredientsandbuildingcostsarelowerbecausenoseparategrindingbinsareneeded.Thedisadvantagesarethatindividualingredientscannotbeselectivelyreducedtoadesiredparticlesizeandthemixingsystemisdirectlydepend-entuponthegrindingcapacity.
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Dependingontherequiredcapacity,theparticlesizedistributionrequirements,andotherdevelopmentsinthemarketplace,differentgrindingmachinesmaybeused.
A tootheddiskmill canbeused forbreakingofgrainaheadof flaking, forpoultryfeed production and for detaching and grinding of minerals. Its advantages are easeofoperationandlowpercentageoffines,anditsdisadvantagesarethe lowthroughput(approximately4000kg/hr)andalackofabilitytovarytheparticlesizedistribution.
Arollermillisusedifaparticlesizedistributionofmaximumuniformityisrequired.Itsadvantagesarealowpowerrequirement,sizereductionisaccomplishedgentlyandwithoutalotofheatgenerationandthereisanarrowparticlesizedistribution.Itsdisad-vantagesareahighcapitalinvestment,itsunsuitabilityforfibregrinding,itsexpensivedesignanditslimitedinputparticlesize.
A conventional hammer mill is considered the universal grinding machine in feedmanufacturingand itallowssizereductionofalldry feed ingredients. Itsadvantagesareitsuniversalapplicability,highpossiblethroughputs,easyvariationofparticlesizedistribution,simpledesignandeasyoperation. Itsdisadvantagesareitswideparticlesizedistributionandahighpowerrequirement.
Thedevelopmentoftheverticalrotor (hammer)millhasopenednewpossibilities inthegrindingprocess.Comparedtoconventionalhammermills,itsadvantagesarethatnoexhaustsystemisrequired,thereisalowerburdenontheenvironment,thereisnolossofmoisture,ithasalowpowerrequirement,ahigherthroughputandalowernoiselevel.
3.�. Conveying Pneumaticsuctionsystems,pneumaticpressuresystems,ormechanicaltransportsys-temscanbeusedforconveyingmaterialsaftergrinding.Becauseoftheirhighoperat-ingcosts,pneumaticconveyingisgenerallyappliedforlow-capacityplantsonly.
3.�. mixing, addition of liquids, and homogenizationMixers are the main machines in feed plants. Their function is to uniformly mix theindividualrawingredients,whoseparticlesizesandbulkdensitymayvaryconsiderably.Micro-ingredientsmaybegravimetricallyaddedinthemixerusingspecialdispensingunitsorbyhand.
In the feed manufacturing industry, the mixers almost exclusively used are of thebatchtype,inwhichentireunits(normally500–5000kg,dependingonthemixersize)arepre-weighed,groundandthenmixed.Thistypeofmixingsystemensuresahomo-geneousproduct.
Themixersize,type(verticalorhorizontal)andmixingtimedeterminethecapacityofabatchmixingsystem.Dependingonthetypeofmixerused,themixingtimeswillvaryconsiderably.Forexampleusingaverticalmixerwithscrew,themixingtimewillbeapproximately10-30minutes,andifusingahorizontalmixerwithribbonflightorpad-dles,themixingtimewillbeapproximatelyonetofourminutes.Generally,horizontalmixerswithcountercurrentmixingactionononeshaftwillachievetherequiredmixingqualitywithintheshortesttime.Allmixersshouldmeetthefollowingstandards:
• Themixingaccuracyshouldbeguaranteedatadilutionof1:100000.• Homogeneityshouldbeachievedwithintheshortesttimepossible.• Thematerialtobemixedshouldbehandledgentlyaspossible.• Whenthemixerisemptied,residuesshouldbeatanabsoluteminimum.• Themixershouldbeadaptableforadditionofliquids.
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Inhorizontalmixers,thedryingredientsarefedbatchbybatchintothemixerwhiletherotorisrunning,andarehomogeneouslymixedinthemixingchamber.Themixingtimeisgenerallytwotofourminutes.Horizontalbatchmixersmaybeequippedwithapaddlerotororaribbonflightrotor.
Withribbonflightrotors,loadingispossiblealongtheentirelengthofthemixer.How-ever,partialbatchesmustbeloadedataminimumof50%capacityandribbonflightchangesarelabour-intensive.Theexpectedresidueisabout0.2%.Withpaddlerotors,loadingisonlypossibleinthecentrebutpartialbatchesdownto20%arepossible.Thepaddlesareadjustable,andthematerialsaremoregentlytreated.Theexpectedresidueis<0.2%.
The use of horizontal speed mixers can contribute to the plant flexibility and toreductionofcontamination.Comparedtoconventionalhorizontalmixers,speedmixershave:
• shortermixingtimes(1.5minutes);• athroughputofupto20batches/hour;• smallermixer,scalesandhoppers;• fastandcompletedischarge;• aresiduelevelofonly0.05%• atroughshape(length:depthratio=1:1);• norequirementforanairreplacementduct;• norestrictionregardingfilling;• easiermaintenance.
Theadditionofliquidingredientstofeedsisbecomingincreasinglyimportant.Liquidsmaybeaddedinordertobeabletouselessexpensiveby-productsfromotherproductionprocesses,toenrichenergy,tocontroltaste,smellandcolour,toreducedustgenerationandsegregation, to increasemoisturecontentand to improvepreservation.Commonliquidsincludewater,fats/oils,molasses,propionicacidandflavouringagents.Becauseoftheirviscosity,fats,oilsandmolassesmustbeheatedtoacertaintemperaturebeforetheycanbeaddedtofeeds.Thepointoftheprocessatwhichtheliquidisaddedandtherateofadditiondependsonthetypeandquantityofliquidtobeused.
Abatchmixer isgenerallynotsuitable for theadditionof liquids to the feed,how-everitmaybepossibleiftheadditionrateislowerthan5%.Otherwise,problemsmayincludelumpformation,contaminationofrotorandtrough, increasedpowerrequire-mentandincreasedamountofresidue.
Inthefeedindustry,homogenizationistheincorporationofliquidsintodrysolidsinacontinuousprocess.Homogenizersoperateatfairlyhighrotaryspeedsandensurethor-oughintermixingoftheliquidwiththesolids.Homogenizersmaybeusedaheadoforafterthebatchmixer,andcanhandlethesimultaneousadditionofuptothreeliquids.
3.�. pelletingThe purpose of pelleting is to transform a loose, mealy bulk material into normallycylindricalpelletsbycompactionandshaping.Pelletedfeedoffersanumberofadvan-tagesoverfineandcoarsemeal-typefeeds.
• Benefitstothefeedproducer:- lessstoragespaceandsmallerconveyersrequired;- costreduction(lowercostrawmaterialscanbeused);- lowerriskofsegregationandcontamination.
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• Benefitsinstorage/handling:- simplerdischargefrombins;- nosegregationduringbulkhandling;- bridging(feedflowblockageduringdischarge)inbinsisreduced;- lessdustisgenerated.
• Benefitstotheanimal:- higherdegreeofnutrientassimilation;- reductionofbacterialandfunguscountsinfeeds;- allconstituentsofthemixareavailableinuniformproportions.
Thepelletmillconsistsofthreemajorcomponents:(1)thescrewfeederwhichallowsavolumetricdischargeof themashfromthepelletmillsurgehopper, (2) themixingandconditioningsectionwhichallowsconditioningofthemashwithadditionofsteamand liquids (usuallymolasses),and (3) thepelletmillwhichcompacts themashandshapesitintopellets.Withinthepelletmill,themainpelletingcomponentsarethedieand the rolls. After the mash has been distributed between the rolls and across thewidthofthedie,theactualpelletingprocessstartsatthemomentthelayerofmashtouchestheroll.
Asaresultoftheever-increasingqualityandsanitationrequirementsthatmustbemet,andbecauseofthegreateruseof inexpensiverawmaterialswithpoorpelletingcharacteristics,itisoftennotpossibleusingtheconventionaldirectpelletingprocesstoachievethenecessarybindingforcesformakinghighqualitypellets(Figure2).There-fore, a double pelleting system was developed that considerably improves the pelletqualityandsimultaneouslyallowsahigherthroughput.
FigUre 2
Factors having a fundamental influence on the pelleting process and the final product
Source:adaptedfromNef(2002).
Raw product/mashParticle sizeParticle formProduct densityProduct moisturePelleting aids
Machine componentsDieRollDie speedRoll gap
Processing systemConditioningThroughputFines returnLiquid addition
FACTORS
Pelletability
QualityStabilityHardnessAbrasionEnergy
ASPECTS OF THE RESULTING PELLET
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3.�. Heat treatment and coolingThe demand for safe and hygienically produced feeds is increasing, not only in thedomesticandinternationalmarketsbutalsofromconsumers.EndproductsmustbeasfreeaspossiblefromSalmonellaSpp.andotherharmfulbacteria.
Heattreatmentisthemosteffectiveandeconomicalmethodofdestroyingbacteriaandotherpathogensinlivestockfeedsandimprovingthequalityoffeeds.Heattreat-ment, through theprocessof expansion,alsoenhances thequalityof energy, as thestarchinthefeedbecomesmoreavailable(especiallytonon-ruminants).Thetwomostcommonheattreatmentmethodsarepelletingwithheatshieldandtheapplicationofexpanders.
Byequipping thepelletingmillwithadoubleconditionerheatshield, theretentiontimeinthemixer-conditionersectionincreases.Theoptimaltemperatureismaintainedbymeansofelectricalsurfaceheatingandadditionofhotair.
Expandersmaybeappliedasanindependentprocessstageorincombinationwithapelletmill.Typicalapplicationsofexpandersinclude:
• salmonellacontrolforbroilerandlayinghenfeeds;• productionofcrumblesforslurryfeedingofpigs;• starchgelatinizationforyounganimals,especiallypiglets;• productionoflowabrasionpellets;• productionofcattlefeedwithhighliquidadditionrates.
Pelletsaredischargedfromthepelletmillatatemperatureofapproximately80°C.Inaddition,theyarestillmoistandsoftandthereforecannotbepackedorstoredbeforetheyhavecooledtoatemperaturenormally5to10°Cabovetheambienttemperatureandhavehardened.Themostcommoncoolertypesarehorizontal (belt type)coolersandcountercurrentcoolers.
Horizontalcoolerscanbeusedforalltypesandsizesofproducts,althoughtheyhaveahighspecificairrequirementandarelativelylargespacerequirement.Countercur-rentcoolers canonlybeused for free flowingmaterialsandpelletswithasizeofupto10mmbuthavealowspecificairrequirementandarelativelysmallspacerequire-ment.
4. REFERENCESNef E. 2002. Manufacturing of compound feed. Swiss Institute of Feed Technology, Uzwil,
Switzerland.http://www.sft-uzwil.ch/en/home/home_en.asp.
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LIvESTOCk FEED REGULATIONS AND INDUSTRy GUIDELINES
1. GENERAL CONCEpTSThe appearance of TSEs has presented new challenges to countries throughout theworld.Inordertoprotectbothdomesticpublicandanimalhealthandmaintaintradeinanimalsandanimalproducts,manycountrieshaveimplementedsomemeasurestocontrolandpreventTSEs,andBSE inparticular.Thesemeasuresvarywidelyamongcountries,butgenerallyincludesomeformoffeedbaninordertopreventruminantsfromingestingmaterialderivedfromruminants,asdescribedinthe“Overview:Imple-mentationofTSEmeasures”chapterinthiscoursemanual.
Internationalrecommendationsandregulationshavebeendevelopedtoimprovepub-licandanimalhealthandfacilitatefairtradethroughthestandardizationofBSE-relatedmeasuresacrosscountriesandregions.Nationalregulations,practiceguidelinesandcodes of practice have been developed to help countries and individual agriculturaloperationseffectively implement themeasures inplace.Manyorganizationsatmanylevelsparticipateindevelopingthesedocuments.InFigure1,theinternational,nationaland industry framework that contributes to the overall safety of animal feed in the
FigUre 1
The network of players contributing to the goal of international food and feed safety
OIE:WorldOrganisationforAnimalHealthIppC:InternationalPlantProtectionConventionwHO:WorldHealthOrganizationFAO:FoodandAgricultureOrganizationEU:EuropeanUnion
FEFAC:EuropeanFeedManufacturers’FederationGAFTA:GrainandFeedTradeAssociationAFIA:AmericanFeedIndustryAssociationIFIF:TheInternationalFeedIndustryFederationwRO:WorldRenderers’Organization
International Food andFeed Safety
IPPC OIE CodexAlimentarius WHO FAO
EU 171 Member Countries of the Codex Alimentarius
MemberStates
FEFAC GAFTA AFIA IFIF WRO
International
National
Industry
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world,aswellaswithrespecttoBSE, isshown. It isclearthatcountriesoutsidetheCodexAlimentariusalsocontributetoandparticipateinthisprocess.
2. INTERNATIONAL STANDARDS AND NATIONAL/REGIONAL REGULATIONS WTOconsidersthestandardssetandrecommendationsmadebytwointernationalbod-ies,theCodexAlimentariusCommissionforfeedandfoodissuesandtheOIEforanimalhealthissues,tobetheinternationalstandards.Inaddition,countriesandregionsadoptand implement legislation that should be in line with these international standards.LegislationoftheEUandtheUSAaregivenhereasexamples.
2.1. The Codex Alimentarius In 1963 the Codex Alimentarius Commission was created by the WHO and FAO todevelop food standards, guidelines and related texts such as codes of practice. Themainpurposesaretoprotectthehealthofconsumers,toensurefairtradepracticesinthefoodindustry,andtopromotecoordinationofallfoodstandardsworkundertakenbyinternationalgovernmentalandnon-governmentalorganizations.TheoutputfromtheCodexCommissioniscalledtheCodexAlimentarius,whichcomprehensivelydescribesbasicprinciplesoffoodhygiene,andisavailableathttp://www.codexalimentarius.net.
Atthe23rdSessionoftheJointCodexAlimentariusCommissionin1999,anAdHocIntergovernmentalCodexTaskForceonAnimalFeeding(hostedbytheDanishGovern-ment)wasestablishedtodevelopadraftcodeofpracticeonanimalfeeding.Thiscodeof practice was presented and approved by the Codex Commission in July 2004, andappliesinadditiontothebasicprinciplesalreadyestablishedintheCodexAlimentarius(CodexAlimentarius,2004).Itaimstoestablishafeedsafetysystemforfood-producinganimals,andcomprehensivelycoversthefoodandfeedchainstakingintoaccountrel-evantaspectsofanimalhealthandtheenvironmentinordertominimizepublichealthrisks.Thefullcodeofpracticecovers:
• generalprinciplesandrequirementswithrespecttofeedingredients;• labelling;• traceability/producttracingandrecord-keepingoffeedandfeedingredients;• inspectionandcontrolprocedures;• healthhazardsassociatedwithanimalfeed;• feedadditivesandveterinarydrugsusedinmedicatedfeed;• feedandfeedingredients;• undesirablesubstances;• production,processing,storage,transportanddistributionoffeedandfeed ingredients;• receiving,storageandtransportation;• personneltraining;• sanitationandpestcontrol;• equipmentperformanceandmaintenance;• manufacturingcontrols;• recalls;• on-farmproductionanduseoffeed;• goodanimalfeedingpractice;• methodsofsamplingandanalysis.
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Althoughthecodeofpracticedoesnotspecificallyrefertotheuseofanimalproteinsin feed, it does cover regulation and control of animal feed manufacturing includinglabelling,traceability,inspection,production,processing,storage,transport,samplingand analysis, and training. These aspects ultimately contribute to assuring effectiveenforcement of BSE measures in place, including feed bans and prevention of crosscontamination. The code of practice not only covers production at feed-producingplants,butalsocoverson-farmmanufactureoffeed.ThisisimportanttoBSEcontrol,asrawmaterialsprohibitedforuseincertainlivestockspeciesmaybeusedinappro-priatelyunderlooserprivatecontrol.
Furtherinformationonrelevantaspectsofcontrolandsafetythatarenotcoveredinthecodeofpracticemaybe found inotherCodexstandards (e.g.GeneralPrinciples,FoodLabelling,MethodsofSamplingandAnalysis).
2.2. Terrestrial Animal Health Code of the world Organization for Animal Health The OIE (http://www.oie.int/) is an intergovernmental organization representing 167membercountries.TheOIEcollects,analyses,andmakesavailablethelatestscientificinformation on animal diseases and disease control throughout the world. Scientificstandardsarethendevelopedbasedonthis information.Thestandardsarepreparedby elected specialist commissions and working groups comprising internationally-renownedscientists,mostofwhomareexpertswithinthenetworkof156OIEcollabo-ratingcentresandreferencelaboratories.Afteradoption,thestandardsaremadeavail-ableastheTerrestrialAnimalHealthCode(OIE,2005a)andtheManualofDiagnosticTestsandVaccinesforTerrestrialAnimals(OIE,2005b).Similarstandardsareavailableforaquaticspecies.
BecausetheOIEsetsstandardsforanimalhealthissues,itdoesnotprovidespecificguidanceonfeedproductionorfeeding.However,itdoesprovidespecificinformationonBSE(OIE,2005c),aswellasrecommendationsonwhatproductsaresafetotradeunderwhat conditions (OIE, 2005a). The OIE code recommends thatRuminant-derived meatandbonemealorgreaves,oranycommoditiescontainingsuchproducts,whichorigi-natefromacountry,zone,orcompartment(withnon-negligibleBSErisk)shouldnotbetradedbetweencountries(OIE,2005d,Article2.3.13.12),whichclearlymeansthattheseruminant-derivedproductsfrommostcountriesshouldnotbetraded.
Inaddition,recommendationsforTSEinactivationintheproductionofmeatandbonemeal(MBM)aregiven(OIE,2005d).Otherrecommendationsaremadefortradeinotherproducts,accordingtoacountry’sBSEstatus.TheOIErecommendationsforsurveil-lanceanddiagnosisofBSEaredescribedmorefully inthe“IntroductiontoTSEsandBSE”chapterinthiscoursemanual.
2.3. Regulations of the European Union TheEUcomprisesof25Europeanstates(countries)andwasestablishedbytheTreatyonEuropeanUnionin1992(althoughmanyelementsoftheUnionhaveexistedsincethe1950s).TheEUunitesitsstatesinmanyaspects,includingacommonsinglemarketconsistingofacustomsunionandasinglecurrency(adoptedby12outof25memberstates),aswellasasingleagriculturalpolicy.
GiventhatBSEwasfirstidentifiedintheUKandthatinitialspreadwasmostevidentwithin the EU, comprehensive regulations have been put in place to provide for the
management of
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spongiform
encephalopathies
in livestock feeds
and feeding
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controlandeventualeradicationofBSE.AsadditionalcountrieslooktowardsbeginningtheEUaccessionprocess,orwishtoexpandtheiropportunitiesfortrade,theEUregu-lationsmustbeconsidered.Thus,manyothercountriesthroughouttheworldarebas-ingtheirneworrevisedregulationsonthoseoftheEU.Consequently,bansandothermeasures implementedbytheEUcontinueto influencetheworldmarket inanimalsandanimalproducts.
ThechronologyofadoptionofthemainEUregulationsisgiveninTable1,andspe-cificregulationscanbefoundontheEUWebsite(EU,2005).Theseregulationsaffectnotonlythemembercountries,butalsoothercountriesintheiractionsandtradewiththeEU.IndividualEUstatesmayhavetheirownrulesforimplementationbutallmustultimatelycomplywiththeEUregulations.
In 1��4,allproteinderivedfrommammalswasformallyprohibitedforuseinrumi-nantfeedintheEU(EU,1994),althoughsomememberstateshadimplementedsuchabanbeforethatdate.However,therewasnoprohibitionagainstexportofthesemateri-alsatthattime.
In 1��� and 1���,theEUformallyprohibitedexportofmammalianMBM(andrelatedproducts)fromtheUKandPortugal(respectivelyintheseyears)totherestoftheEUandthirdcountries(EU,1996and1998).
In 2001, theEUadopteda regulation layingdown rules for theprevention, controlanderadicationofcertainTSEs(“theTSERegulation”;EU,2001),whichprohibitsthefeeding of mammalian protein (except gelatine from non-ruminants, milk and milkproducts,andeggsandeggproducts)toanyfarmedanimal.Thisbanisoftenreferredtoasthe“totalfeedban”.TheregulationalsosetsoutmorerestrictiveregulationsformemberstatesorregionsintheGeographicBSERiskAssessment(GBR)categoryIV(i.e.currentlyUKandPortugal;adescriptionoftheGBRisgiveninsection6.2ofthe“IntroductiontoTSEsandBSE”chapterinthiscoursemanual).
CurrentlyintheEU,exportofprocessedanimalproteinsderivedfromruminants(andproductscontainingsuchproteins)intendedforfeedinglivestockisprohibitedfromtheentireEUtothirdcountries.However,fishmealandsomebloodproducts(butnotbloodmeal)canstillbeusedinfeedintendedfornon-ruminants.
TheEUregulationsarecontinuallybeingupdatedanditcanbedifficulttoextractthemostcurrentandrelevantinformation.Manyspecificdecisionsarenolongerinforce,andtherelevantregulationshavebeenincorporatedintoothercurrentlegislation.How-ever,updatedsummariesofnewinformationonallBSEtopicscanbefoundontheEUWebsite(EU,2006).Currently,thefollowingtworegulationsdirectlyapplytothefeedingoflivestockinthefaceofBSE.
Regulation1774/2002.MostoftheEUanimalby-productslegislationhasbeencon-solidated into the text of Regulation 1774/2002 (EU, 2002), which categorizes animalby-products(animalcarcases,partsofanimalcarcasesandproductsofanimaloriginwhicharenot intended forhumanconsumption)according to riskandcontrols theiruse and disposal. Regulation 1774/2002 also includes a fairly general prohibition onthefeedingofaspecieswithmaterialderivedfromthesamespecies.Thisregulationisdiscussedindetailinthe“Renderingofanimalby-products”chapterinthiscoursemanual.
Regulation882/2004.In2004,theEUadoptedanewregulationlayingdownrequire-mentsforfeedhygiene(EU,2004),whichdetails:
• compulsoryregistrationofallfeedbusinessoperatorsbythecompetentauthority;
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TABLE 1. principle legislation on TSE regarding animal feed in the European Union, including legislation number, date, and title
year Livestock Feeds/TSE-relevant legislation number, date and title (or topic)
1989 D89/469/EECof28July1989.RestrictionsonthedispatchofcertainlivecattlefromtheUK1994 D94/381/ECof27June1994.Banontheuseofproteinsderivedfrommammaliantissues forfeedingruminants D94/382/ECof27June1994.RenderingsystemsforprocessingruminantwasteintoMBM (inactivationofBSEagents) D94/474/ECof27July1994.RestrictionsonthedispatchfromtheUKoflivecattleandcertain ruminantproducts-Destructionofspecifiedbovineoffal(RepealsD89/469/ECand90/200/EC)1995 D95/29/ECof13February1995.AmendmentofD94/382/EC-Batchrenderingsystems D95/60/ECof6March1995.AmendmentofD94/381/EC-Derogationtothefeedban1996 D96/449/ECof18July1996.PressurecookingsystemforprocessingmammalianwasteintoMBM (inactivationofTSEagents)1997 D97/534/ECof30July1997.ProhibitionoftheuseofSRM(mainlybrain,eyesandspinalcord) D97/735/ECof21October1997.RestrictionsontradeinMBM1999 D1999/129/ECof29January1999.AmendmentofD94/381/EC-Hydrolysedproteins D1999/534/ECof19July1999.ConditionsfortheproductionofMBMandtallow(RepealsD96/449/EC) D1999/881/ECof14December1999.Postponementto30June2000ofthedateofapplicationof D97/534/EC(SRM)2000 D2000/418/ECof29June2000.ProhibitionoftheuseofSRM(RepealsD97/534/EC) D2000/766/ECof4December2000.TemporarybanonuseofMBM2001 D2001/2/ECof27December2000.AmendmentofD2000/418/EC–ExtensionofthelistofSRM (bovineintestines) D2001/9/ECof29December2000.Conditionsforfeedingcertainanimalproteins D2001/25/ECof27December2000.Prohibitionoftheuseofdeadanimalsintheproductionof animalfeed D2001/165/ECof27February2001.AmendmentofD2001/9/EC–Hydrolysedproteins D2001/233/ECof14March2001.AmendmentofD2000/418/EC–ExtensionofthelistofSRM (vertebralcolumn) D2001/270/ECof29March2001.AmendmentofD2000/418/EC–Importsfromthirdcountries R2001/999/ECof22May2001.Rulesfortheprevention,controlanderadicationofcertain transmissiblespongiformencephalopathies2002 R270/2002of14February2002.AmendmentofR999/2001–SRM,surveillance,animalfeedingand placingonthemarketofovineandcaprineanimalsandproductsthereof R2002/248/ECof27March2002.AmendingCouncilD2000/766/ECandCommissionD2001/9/ECwith regardtothefeedingofanimalproteins R2002/1774/EC.Layingdownhealthrulesconcerninganimalby-productsnotintendedfor humanconsumption2003 R1234/2003of10July2003.AmendmentofR999/2001–introducingthecurrentprovisionsofthefeed banintoRegulation(EC)No999/2001withoutafixedtimeschedule,thusendingthetransitional natureofthefeedban2004 D2004/653/ECof16September2004.AmendmentofCommissionDecision2001/376/ECasregards thedispatchofmeat-and-bonemealofmammalianoriginandrelatedproductsfromPortugal2005 R1292/2005of5August2005.AmendmentofR999/2001asregardsanimalnutrition.0
Note:R:Regulation,D:Decision.Source:Derivedfrom:http://ec.europa.eu/food/food/biosafety/bse/chronological_list_en.pdfaccessed,UpdateofFebruary2006.Updatesavailablethroughhttp://ec.europa.eu/food/food/biosafety/bse/legisl_en.htm.
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• maintenance of the approval system for feed businesses dealing with sensitivesubstances;
• operationofallfeedbusinessesinaccordancewithharmonizedhygienerequire-ments;
• applicationofgoodhygienepracticeatalllevelsofagricultureproductionanduseoffeed;
• introductionofHazardAnalysisCriticalControlPoint(HACCP)principlesforfeedbusinessoperatorsotherthanatthelevelofprimaryproduction;
• compulsoryrequirementsforfeedproductionatfarmlevel;• anEUframeworkforguidestogoodpracticeinfeedproduction;• provisionthatfeedbusinessoperatorsareonlypermittedtoimportfeed,including
singlefeedmaterials,fromcountriesoutsidetheEUiftheexportingcountryandtheestablishmentcomplywithspecificrequirementsandappearonalist.FeedfromsuchestablishmentswillneedtocomplywiththerequirementsoftheFeedHygieneRegulation;
• an endorsement of the principle that feed business operators must provide afinancialguaranteeinordertocovertherisksrelatedtotheirbusinesses.
2.4. Rules of the Food and Drug Administration, United States of AmericaIn1997,theFoodandDrugAdministration(FDA)oftheUSApublishedarule(herein-afterreferredtoasRule21;FDA,1997)describingthatmammalianproteinforuseinruminantfeedisconsideredafoodadditive.Thus,intheUSA,theuseofanymaterialthatcontainsmammalianproteinisprohibitedinruminantfeed,thoughinsomecasespureporcineorpureequinematerialsfromsingle-speciesslaughterfacilitiesmaybefedtoruminants.
According to the rule, renderers, protein blenders, feed manufacturers, and dis-tributors that manufacture, blend, process, and distribute products that contain (ormay contain) mammalian protein and that are intended for use in animal feed mustproperlylabelthematerialswiththewords‘‘Donotfeedtocattleorotherruminants’’andmustmaintain(andmakeavailabletothecompetentauthority)recordssufficienttotrackthematerialsthroughouttheirreceipt,processinganddistribution.Moreover,rendererswhoobtainruminantornon-pureporcineorequinematerialsmust imple-mentsufficientmeasuresinordertopreventcrosscontaminationofproductsthatmaybeusedforruminants.Theymustalsomaintainwrittenproceduresspecifyinginthesemeasurestheproceduresforseparatingproductsfromthetimeofreceiptuntilthetimeofshipment.
In addition, establishments and individuals that are responsible for the feeding ofruminantanimalsmustmaintaincopiesofpurchaseinvoicesandlabellingforallfeedsreceivedthatcontainanimalproteinproducts.
Following thereportingofaclinicalcaseofBSE in theUSA inDecember2003,aninternationalreviewteamwasinvitedtoconsidertheresponsetothisfinding. InJuly2004, subsequent to this review, the FDA described potential measures related toanimalfeed(USFDA,2004a).Thesemeasures,intendedtoreducetherisksthrough-out feed manufacturing and distribution and on the farm (due to misfeeding) and todecreaserecyclingof theagent (includinganSRMbanfor feed),wereproposedasaruleinOctoberof2005(USFDA,2005).
Inaddition,FDA(USFDA,2004b)measuresprohibittheuseofbovinematerialsthat
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could carry the BSE agent in cosmetics and human foods, including certain meat-based products and dietary supplements. These high-risk bovine materials includeSRM(includingbrain,skull,eyes,andspinalcordofcattle30monthsofageorolder,andsmallintestineandtonsilsfromallcattle),materialfromnon-ambulatorydisabledcattle, material from cattle not inspected and passed for human consumption, andmechanicallyseparatedbeef.
MuchasintheEU,individualstatesintheUSAmayhavetheirownrulesforimple-mentation,butallstatesmustultimatelycomplywiththeFDA(andotherfederal)rules.AlsoaswiththeEU(andmostcountries),officialrulesandlegislationarecontinuallybeingupdatedasnewinformationbecomesavailable.Themostrecentlegislationmustalwaysbecompliedwith.
3. ImpLEmENTATION OF INTERNATIONAL AND NATIONAL STANDARDS AND REGULATIONS: INDUSTRy GUIDELINESThevariousinternational,regionalandnationalrecommendationsandregulationsallincludethebanningofruminantand/orallmammalianproteininanimalfeedandtheidentification,labellingandtraceabilityofsuchmaterialsthroughthefeedchain.Theyalsoattempttoensurethatthereisnocrosscontaminationoffeedingredientsallalongthefeedchaininordertopreventevenextremelysmallquantitiesofinfectivematerialfrombeingfed.Figure2showstheanimalfeedchainandthevariousstepsandstake-holdersthatneedtocomplywiththeseregulations.
Theanimalfeedindustryandvariousstakeholdersinthefeedchainhavethereforedevelopedcodesandguidelinestofacilitatecompliancewiththerecommendationsandregulations.Someofthemajorcodesandguidelinesaredescribedbelow.
3.1. Grain and Feed Trade Association The Grain and Feed Trade Association (GAFTA: http://www.gafta.com/) is an interna-tionaltradeassociationforgrainsandotherfeeds,with930membersin80countries.It provides standard forms for contracts, training and professional development, adisputeresolutionservice,arbitrationandmediation,schemesforsuperintendentsandanalysts,aswellasinformationresources,notablytheGAFTATraders’Manual(GAFTA,2004),whichprovidesstandardsofbestpracticeforalltradeoperations.
TheGAFTAstandardfortheinternationalgrainandfeedtradeisanall-encompass-ingsystemtoprovidesafefoodandfeedmaterialsworldwide.UsingaHACCP1-basedapproach,itlinksthe“bestpractices”fortransport,storage,loading,discharge,super-visionandanalysisfromthefarmonwardsforallcombinablecropsanddry,moistandliquidanimalfeedmaterials.Therearesevenmajorsections:
• Storage-describingthestorageofcombinablecrops,anddry,moistandliquidanimalfeedsfromfarmonwards.
• Loading,discharge,supervisionandhandling-describingeachoftheselogisticaloperationswithreferencetotheGAFTAweighingrulesandtheGAFTASuperin-tendentsscheme.
1HazardAnalysisandCriticalControlPoints(HACCP)isdescribedinthe“Qualitycontrolconcepts,hygiene,andHACCPinthemeatindustry”chapterintheCapacityBuildingforSurveillanceandPreventionofBSEandOtherZoonoticDiseasesprojectcoursemanualManagementoftransmissiblespongiformencephalopathiesinmeatproduction(FAO,2007).
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• Analysis-describinganalysisthroughoutthesupplychain,withreferencetoalltheGAFTAmethodsofanalysisandtheGAFTAanalystsscheme.
• Transport - describing all transport operations from farm onwards, includingroad,rail,waterwayandsea.
• Pestcontrolandfumigation-describingminimizationoflossesanddamageandanintegratedpestprogramme.
• IntroductiontoHACCP-describinghowtheHACCPapproachistakentominimizelosses,damageandcontaminantrisks.ThebasicsofapplyingHACCPtothesup-plychainareexplained.
• Audit/verification–becausecertainimportmarketsrequiretraderstohavetheirsupply operations independently audited/verified, this section describes how togainGAFTAverification.
Toensureconformity,GAFTArequiresverificationofeachtrader’sofficeannuallyforthefirstthreeyears,thenonceeverytwoyearsthereafter.VerifiersmustbeindependentandaregovernedbytheirownGAFTACodeofPracticetoensuretheiroperationscon-stantlycomplywiththecriteriaandtheymustinformGAFTAofallverificationresults.
FigUre 2
Schematic of the livestock feed production chain and the areas to be considered in developing codes of
practice.
Crop producers
Raw materials
Feed mill
Farmer
Abattoir
Consumer
Export
Processor
Import
Transport
Transport
Transport
Transport
Transport
The Feed Chain
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3.2. International Feed Industry FederationThe International Feed Industry Federation (IFIF; http://www.ifif.org/) is an organiza-tionthatrepresentsnationalandregional feedassociationsandfederationsandoth-ersinvolvedintheproductionofcompoundanimalfeeds.MembersofIFIFaremainlynational associations, corporate/commercial members (suppliers to the feed trade),andotherfeed-relatedorganizations.TheIFIFhasobserverstatusintheCodexAlimen-tariusandisworkingcloselywithFAOinthepracticalimplementationoftheCodexcodeofpracticeonanimalfeeding,describedinsection2.1ofthischapter.
3.3. American Feed Industry Association TheAmericanFeedIndustryAssociation(AFIA;http://www.afia.org/)isthefeedindustryassociationfortheUSA.Itincludes690membercompanies,representingnearly75%of the commercial feed and pet food sold annually in the USA. The AFIA’s membersinclude manufacturers, ingredient suppliers, animal health companies, equipmentmanufacturers, large integrated livestockandpoultryproducers, and firmsprovidingothergoodsandservicestothecommercialanimalfoodindustry.Inaddition,AFIAalsoincludesmorethan35state,regional,nationaland internationalassociationsamongitsmembership.
The AFIA publishes the Feed Manufacturing Technology manual, which is revisedannually. Thechapteronqualityassurancedescribescontrolsaimed topromote theproductionofproductsthatconsistentlymeetpredeterminedqualitystandards.Itcom-prehensivelydescribesanin-plantqualitycommitmentprogrammeincludingpolicies,procedures,sampling,andtestingrelevanttofeedproductionintheUSA.
TheAFIAalsopublishesaguidetohelpfeedmanufacturerscomplywiththeFDARule21prohibitingmammalianproteininruminantfeed(AFIA,2001).Thespecificrequire-mentsinthethreeprincipalareas(labelling,record-keeping,andequipmentcleaning)aredetailed.Thisguideisdesignedforplantsthatmanufacturefeedformorethanonespecies,andthatuseMBMorothermammalianproteins.Itemphasizesthatspecificwrittenproceduresmustbedevelopedandusedforeachindividualfacility.
Itshouldbenotedthat,althoughmeetingtheseguidelineswillallowcompliancewiththeFDArulesandBSEmeasuresintheUSA,thesemeasureswillnotoptimallypreventcrosscontaminationwithBSEinfectivity,asdescribedinthe“Overview:ImplementationofTSEmeasuresforlivestockfeeds”chapterinthiscoursemanual.
3.4. European Feed manufacturers’ Federation TheEuropeanFeedManufacturers’Federation(FEFAC;http://www.fefac.org/)consistsofnationalassociationsfromEUmemberstatesasfullmembers,andmanyobservermembersfromnon-EUcountries.Asanindependentorganization,FEFACrepresentstheEuropeanfeedindustryinEUlegislativenegotiations,andholdsobserverstatusintheCodexAlimentarius.
Moreover, FEFAC develops professional rules and good manufacturing practicesfor improving the quality and safety of compound feed. It has published the FEFACguidelinesfortheimplementationofacodeofpracticeforthemanufactureofanimalfeedingstuffs(FEFAC,2001)covering:
• qualitymanagementandqualitycontrol;• riskanalysis;• undesirablesubstancesandproducts,includingbacteria;
management of
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spongiform
encephalopathies
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• additivesandmedicaments;• facilitiesandequipment;• personnel;• productconceptionandfeedformulation;• productsafety;• production (purchase,delivery,and intake,weighing,grindingandparticlesize,
mixing,pelleting/heattreatment,cooling,storage);• transportandstorage;• documentsandrecords;• registrationofcompoundfeedstuffs;• complaintsandproductrecall.
Inanattempt tomakealloperationsalong the feedchain fullyresponsible for theproductstheydeliver,thisdocumentincludestheimplementationofHACCPprinciplesatallstagesofproduction.Thus,itisstricterthanthecurrentEUlegislation.
In addition, FEFAC lists codes of practice from associations recognized by FEFAC.These include codes of practice developed (or in development) for trade, and for theproductionofanimal fatsandmeals, fishoilsandmealsandotherproductsandby-productsforuseinfeeds.
FEFACalsolistsNationalCodesofPracticedevelopedbyFEFACmembers,including• Códigodeboaspráticasparaofabricodeprémisturasedealimentosparaani-
mais(IACA-Portugal)• GMP-regelingdiervoedersector(ProductschapDiervoeder–TheNetherlands)• CodeGMPgeneralpour lesecteurdel’alimentationanimale (BEMEFA/APFACA
–Belgium)• Codicedibuonepraticheperlaproduzioneelacommercializzazionedialimenti
compostiperanimalidereddito(ASSALZOO–Italy)• Codedebonnespratiquespourlafabricationd’alimentsmédicamenteux–Guide
de mise à niveau pour l’agrément des établissements fabricants des alimentspouranimaux(SNIA–France)
• LeitfadenfüreineGuteHerstellungspraxisvonFuttermitteln(DVT–Germany)• UKASTAFeedAssuranceScheme(UFAS)-CodeofPracticefortheManufacture
ofSafeCompoundAnimalFeedingstuffs(UKASTA-UK)• Code of practice and general operating standard for poultry feed processing
(DAKOFO-Denmark)• Leitfadenfüreine“GuteHerstellungspraxisvonFuttermitteln”,GHF(VSF-Swit-
zerland).
4. SUmmARy OF TSE-RELEvANT CONCEpTS• Mostcountries implementingBSEmeasuresalreadyhavesomesortofbanon
feedinglivestockwithproteinderivedfromanimalby-products.CurrentlyunderdiscussioninthesecountriesisanadditionalbanonSRMinallanimalfeeds,fol-lowingtheexampleoftheEU.
• Internationally-recognizedstandardsforcontrolandpreventionofBSEareavail-ableforgeneralaspectsofrendering,livestockfeedmanufacturingandlivestockfeedinginordertoprotectdomesticpublicandanimalhealthandmaintaintradeinanimalsandanimalproducts.
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• TheregulationsoftheEUregardingimplementationofinternationalrecommen-dations regarding BSEs are currently being adopted or otherwise incorporatedintothelegislationofmanyothercountries.
• Otherinformation,includingseveraldifferentcodesofpractice,isalsoavailablefromgovernmentalandprivatesourcestoprovideadditionaldetailsforeffectivelyandconsistentlyimplementingtheregulations.
�. REFERENCESAFIA (American Feed Industry Association).2001.Guide for feedmanufacturers tocomplywith
the FDA final rule prohibiting mammalian protein in ruminant feed. http://www.afia.org/img/
assets/1209/GUIDE6-2.pdf?GUIDE6-2.pdf
Codex Alimentarius. 2004. Code of practice on good animal feeding, Codex Alimentarius,
Document CAC/RCP 54-2004. http://www.codexalimentarius.net/download/standards/10080/
CXC_054_2004e.pdf
EU (European Union). 1994. Commission Decision 94/381/EC concerning certain protection
measures with regard to bovine spongiform encephalopathy and the feeding of mammalian
derivedprotein(no longer in force).http://europa.eu.int/smartapi/cgi/sga_doc?smartapi!celexa
pi!prod!CELEXnumdoc&lg=EN&numdoc=31994D0381&model=guichett
EU. 1996. Commission Decision 96/239/EC on emergency measures to protect against bovine
spongiformencephalopathy(no longer in force).http://europa.eu.int/smartapi/cgi/sga_doc?sm
artapi!celexapi!prod!CELEXnumdoc&lg=EN&numdoc=31996D0239&model=guichett
EU.1998.CommissionDecision98/653/ECconcerningemergencymeasuresmadenecessaryby
theoccurrenceofbovinespongiformencephalopathy inPortugal.http://europa.eu.int/eur-lex/
pri/en/oj/dat/1998/l_311/l_31119981120en00230031.pdf
EU.2001.ECRegulationNo.999/2001layingdownrulesfortheprevention,controlanderadication
of certain transmissible spongiform encephalopathies. http://europa.eu.int/eur-lex/pri/en/oj/
dat/2001/l_147/l_14720010531en00010040.pdf
EU.2002.ECRegulationNo.1774/2002layingdownhealthrulesconcerninganimalby-products
not intended for human consumption. http://europa.eu.int/eur-lex/pri/en/oj/dat/2002/l_273/
l_27320021010en00010095.pdf
EU. 2004. EC Regulation No. 882/2004 on official controls performed to ensure the verification
oncompliancewithfeedandfoodlaw,animalhealth,andanimalwelfarerules.http://europa.
eu.int/eur-lex/pri/en/oj/dat/2004/l_165/l_16520040430en00010141.pdf
EU. 2005. Eur-Lex legislation search engine. http://europa.eu.int/eur-lex/en/search/search_lif.
html
EU.2006.Europa.Specificthemes(BSE)http://europa.eu/scadplus/leg/en/s89500.htm
FAO. 2007. Management of transmissible spongiform encephalopathies in meat production.Course manual. Project Capacity Building for Surveillance and Prevention of BSE and OtherZoonoticDiseases.Rome
FEFAC (European Feed manufacturers’ Federation).2001.Guidelinesfortheimplementationofa
codeofpracticeforthemanufactureofanimalfeedingstuffs.http://www.fefac.org/
GAFTA (Grain and Feed Trade Association).2004.GAFTAtradersmanual.http://www.gafta.com/
OIE (world Organization for Animal Health).2005a.Bovinespongiformencephalopathy.TerrestrialAnimalHealthCode,Chapter2.3.13.http://www.oie.int/eng/normes/MCode/en_chapitre_2.3.13.
htm
OIE. 2005b. Bovine spongiform encephalopathy. Manual of Standards for Diagnostic Tests andVaccines,Chapter2.3.13.http://www.oie.int/eng/normes/mmanual/A_00064.htm
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OIE. 2004c. Bovine spongiform encephalopathy disease card. http://www.oie.int/eng/maladies/
fiches/a_B115.htm
OIE.2005d.Proceduresforthereductionofinfectivityoftransmissiblespongiformencephalopathy
agents.TerrestrialAnimalHealthCode,Appendix3.6.3.http://www.oie.int/eng/normes/mcode/
en_chapitre_3.6.3.htm
US FDA (Food and drug administration).1997.Rule21substancesprohibitedfromuseinanimal
foodorfeed.USFederalRegisterCFRPart589,Vol.62,No.108,June5,1997.
US FDA. 2004a. Federal measures to mitigate BSE risks: considerations for further action.
APHIS:USDAandFDA:HHS.July8,2004.http://www.fda.gov/OHRMS/DOCKETS/98fr/04n-0264-
nap0001.pdf
US FDA. 2004b. Use of materials derived from cattle in human food and cosmetics, Federal
Register:July14,2004(Volume69,Number134)http://www.fda.gov/OHRMS/DOCKETS/98fr/04-
15881.htm
US FDA.2005. Substancesprohibitedfromuseinanimalfoodorfeed;proposedrule.APHIS:USDA
andFDA:HHS.Oct.6,2005.http://www.fda.gov/OHRMS/DOCKETS/98fr/05-20196.htm
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Quality assurance
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QUALITy ASSURANCE IN FEED-pRODUCING pLANTS
1. GENERAL CONCEpTSTo assure consistent product quality and safety, feed producers must have standardprotocols in place for self-regulation of all of the processes in their feed-producingplant(feedplant).Thisincludeswrittenprocedures,maintenanceofrecords,andperi-odicaudits.QualityassuranceprotocolsarenotonlyimportantfortheimplementationofTSEcontrolmeasures,butalsoformeasurestocontrolorpreventotherdiseasesandfeed-relatedanimalhealthproblems.
Inaddition toself-regulation,mostnationalor localgovernmentshaveauditingorinspectionregulations for feedplants, includingastandardprotocol forofficialsam-plingoffeedsfortesting.Auditsshouldalsofollowstandardizedwrittenprotocolsandadequaterecordsshouldbekept.
A basic concept is that all contaminants (non-desired products and substances,includingprohibitedor restrictedproductsorsubstances)areexcluded fromall feedproductsateachprocessingstep.InthecontextofTSEcontrol,thesecontaminantsandprohibitedmaterialsorproductsincludesomeingredientsofanimaloriginandfeedsorfeedcomponentscontainingtheseingredients.Theexactdefinitionofwhatmateri-als are considered contaminants (and prohibited) depends on the feed ban in place,butgenerallyincludesMBMorothermealsderivedfromruminantsormammals.Thedefinitionalsodependsonthespeciesofanimalsforwhichthefeedis intended(e.g.pets,ruminants,poultry,non-ruminants,aquaticspecies).
Becausethesematerialsmaynotbeconsideredcontaminants(andprohibited)outsidethecontextofTSEcontrol,and/ormaybeallowedforcertaingroupsofanimals,theymaybelegallypresentinfeedplants.Therefore,theterm“crosscontamination”isoftenusedfortheseprohibitedmaterials,while ‘contamination’ isusedformaterialsthatshouldnotbeinanyfeedmaterials(e.g.rodents,birds,rodentdroppings,toxins,mould).
Inthefeedplant,separationoffeedsmustbeassuredandcrosscontaminationmustbepreventedinareasandonequipmentateachprocessingstep,accordingtothespe-cificfeedbaninplaceandothernationalregulations.Majorstepswherecontaminationandcrosscontaminationmayoccurinclude:
• Unloadingoftherawmaterials• Storageoftherawmaterials• Transportoftherawmaterials• Conveying• Cleaning• Drying• Milling• Mixing• Pelleting• Bagging• Transportbetweeneachstep• Transportofthefinalproduct
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• Loadingandunloadingofthefinalproduct• Storageatandbetweeneachstepandstorageofthefinalproduct,includingstor-
ageinsilosandothercontainersatfeedplantsandonthefarm• Feedingequipmentincludingbuckets,bags,andfeedtroughsonthefarm
2. ImpORTANT pOINTS FOR QUALITy ASSURANCEInthefollowingsectionsofthischapter,importantpointsareoutlinedforqualitycontrolinfeedmillsandplantsproducingpremixesandmixedfeedaccordingtotheprotocolsoftheSwissfeedcontrolauthorities(ALP,2004).Theimplementationoffeedbansandthemanufacturingprocessitselfaredescribedinseparatechaptersinthiscoursemanual.
2.1. working areas and production equipmentIngeneral,workingareasandproductionequipmentshouldbeconstructed,arranged,operated,andmaintainedsothat:
• usabilityisoptimizedandtheriskoffailuresisminimized;• theyremaincleananddry;• thoroughcleaningandtheeliminationofforeignbodiesispossible;• adequateaccessisavailableformaintenance;• contamination,crosscontamination,andotherquality-reducingeffects areminimized;• theexclusionofrodentsandotherpestsisoptimized;• themaintenanceandcleaningmaterialsusedareappropriateforfeedproduction
(i.e.non-toxic).Moreover,theproductionequipmentshouldbedesignedinsuchaway,thatthefirst
in first out (FIFO) principle is maximized for all materials (e.g. raw materials, singlecomponentfeeds,mixedfeeds,premixes,feedadditives)inordertooptimizequality.
Working areas and production equipment should be exclusively dedicated to theproductionoffeed,andclearlyseparatedfromotherproductionactivities.Whenplantsproducemultiplecategoriesoffeeds,includingfeedsthatcontainsubstancesthatareprohibitedinothercategoriesoffeeds,theproductionprocessinglinesforthedifferentfeedcategoriesshouldbecompletelyseparated.
Thepotentialhigh-riskareasforcrosscontaminationarespecifictoindividualplantsandequipmenttypes,andthereforemustbe identifiedseparately foreachplant.Thelikelihoodofcontaminationandcrosscontaminationincreasesifallaspectsofthepro-ductionprocessarenotoptimized,includingarrangement,materialflowandequipmentmaintenance.
Theproductionprocessforpremixesandmixedfeedsshouldbedescribedinaflowchart.Theflowchartshouldshowthattheproductionequipmentusedforproductionoffeedscontainingprohibitedmaterialsisseparatedfromthatusedforproductionofothercategoriesoffeed,dependingonthefeedbaninplace,asdescribedinthe“Over-view:ImplementationofTSEmeasures”chapterinthiscoursemanual.Inthiscontext,theproductionprocessesaredividedinthefollowinggeneralsteps:
• delivery/cleaning• storageoftheadditivesandstartingmaterials• grinding• dosage/weighing• mixing/homogenizing
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• pressing• storage• shipment
Additionalplant-specificprocedures(e.g.heattreatment)shouldbeintegratedwhereappropriate.
In order to reduce the risk of contamination and cross contamination, protocolsshouldbe implemented toassure thatallworkingareasandequipment thatdirectlyeffectproductqualityareregularlycleanedandprofessionallymaintained.Theproto-colsshoulddefinefrequency,methodandtheresponsibleperson(s).Protocolstopre-venttheintroductionofpathogenicorganismsshouldalsobeimplemented.Protocolsshouldalsodescribeimplementationofappropriatepathogeneradicationmeasures.
Apreventivepesteradicationprotocol, includingresponsibilitiesandspecific tasks,should be defined and implemented. The entire manufacturing facility, including allstorageareas,shouldbeincludedintheplan.Ifnecessary,theadministrativeandnon-productionareasshouldalsobeincluded.Whenactiveeradicationofpestsisrequired,thetreatmentdate,pesttype,treatmentarea,treatedmaterials,eradicationmaterialsused,quantityof theeradicationmaterialsused,waitingperiod,andsignatureof theresponsiblepersonshouldberecorded.
Workingareasandproductionequipmentthatareofcriticalimportanceforproductqualityshouldbesubjectedtoappropriateandregularinspection.Inspectionshouldbeinaccordancewithastandardprotocolprovidedbythemanufactureroranindependentqualifiedpersonshouldconducttheinspection.
2.2. personnelThe manufacturer must employ sufficient personnel with adequate knowledge andexperiencefortherelevantproductionprocess.
Themanagementpersonresponsiblefortheproductionmustfulfiltherequiredjobspecifications(seesection2.3ofthischapter).Aproxypersonmustbedesignatedtoberesponsible ifandwhentheresponsibleperson isunavailable.Theproxypersonmayeitherberecruitedfromthepersonnelofthesamesectororbeexternaltothatsector.
Anorganizationchartandstaffappointmentprotocolmustbedevelopedthatindicatethe qualifications and responsibilities of management personnel. The chart must bepresented to the competent authorities mandated with inspections. All managementpersonnelmustbeinformedinwritingaboutrequiredtasks,responsibilitiesandcom-petences,especiallywitheveryemploymentchange.Inaddition,managementperson-nelmustbeprovidedwithadescriptionofprofessionalanddisciplinaryauthoritiesfortheirrespectivebranchofproduction.
Position descriptions must also be developed for each other position, and mustincludetheprofessionaltrainingandrequiredskills,assignedtasks,thespecificareasof responsibility (e.g. tostopproductionorshipments, toallowusageorwithdrawal/recallofgoods,torelease/cleargoodsforshipment),andadesignatedproxyperson.
2.3. production processAqualifiedpersonmustbeidentifiedtoberesponsibleforproduction.Thispersonmustbecertifiedinthespecificproductionareaandhavesufficientknowledgeofanimalfeedlegislation, process engineering, and animal nutrition and should meet the followingqualifications:
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• hassuccessfullycompletedaneducationasagronomistoranimalfeedspecialist,orhasanotherequivalenteducation;
• understands what constitutes appropriate working area and production equip-ment,andunderstandstheirconstructional,technical,andhygienicmaintenanceandoperation;
• understandsthecurrentproductionflowchartandoperationprotocolsfromdeliv-erythroughshipment;
• understands when to use authority to stop and/or block production (and musthavethisauthority);
• isfamiliarwiththecriticalpointsofthefacilityandoftheproductionprocessandisabletocontrolthesepointsusingappropriatemeasures;
• isfamiliarwiththecontentsandrequirementsofaqualitycontrolsystemandisabletoimplementsuchasystemintheresponsibleplant;
• isabletodesigndocumentationinsuchawaythatcompletetraceabilityispos-sible;
• knowswhentoauthorizearecall(andmusthavethisauthority)andwhataspectsshouldbeincluded;
• hasknowledgeof the legislativeguidelinesorhasaccess toa competent thirdpersonincaseofquestions;
• hassoundknowledgeofanimalfeedscienceandofanimalnutritionorhasaccesstoacompetentthirdpersonincaseofquestions;
• is aware of his/her responsibilities and is able to transfer information to allinvolvedpersonnelinorderthattheyunderstandthespecificproductionrequire-ments.
The manufacturer must guarantee that the various production processes are con-ductedinaccordancewiththewrittenprotocolsandflowcharts.Theseprotocolsallowthecriticalpoints1oftheproductionprocesstobedefined,auditedandcontrolled.Alltechnical and organizational possibilities must be optimized to avoid contamination,crosscontaminationandothererrors.
Acriticalpointcanbedefinedasastepintheproductionprocessthat,ifnotargetedcontrolisapplied,couldleadtoalossorsignificantdeviancefromtherequiredtargetstate of product quality and safety. Critical points in the production process can bedeterminedusing:
• theHACCP2method;• theplantspecificflowchart;• ananalysisofpossibleplacesforcontaminationorcrosscontamination;• therequiredexaminationsconcerningaccommodationandproduction equipment;• plant-specificprotocolsforthesingleproductionprocesses;• plant-specific technicalandorganizationalpreventivemeasurestopreventcon-
tamination,crosscontaminationsanderrors.
1 The term “critical point” in the production process is used in the context of HACCP methodology, which isacceptedasananalysismethodforfoodsafetyinthefoodprocessingindustry.
2 HACCP is described in the “Quality control concepts, hygiene, and HACCP in the meat industry” chap-ter in the Capacity Building for Surveillance and Prevention of BSE and Other Zoonotic Diseases projectcoursemanualManagementof transmissiblespongiformencephalopathies inmeatproduction (FAO,2007).
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Critical points generally include addition of ingredients to the premixes, additionof premix to the feed, the weighing scale, the measuring devices, the mixer and thechronologicalorderoftheproductionsteps.Often,otherpointsarealsoincluded.
A thorough analysis of the potential for contamination, cross contamination andsources of other errors from delivery through shipment must be made. Moreover,componentresiduesmustbequantifiedstep-by-stepovertheentireproductionproc-ess(usingestimatesortrueobservations).Singleproductionstepscannotbesumma-rizedbyaddition,becauseimportantinformationregardingthelocationofcomponentresidueswillbelostandbecausethepotential individualcausesmustbeunderstoodin order to implement controls. Using a step-by-step analysis it will become evidentwhichtechnicalandorganizationalplant-specificpreventivemeasuresmustbetakenanddocumented.
2.4. Quality controlAqualifiedperson(orpersons)mustbeidentifiedwhoisresponsibleforqualitycontrol.Thispersonmustatleastmeetthejobspecificationsrequiredforthepersonresponsi-bleforproduction(seesection2.3ofthischapter).Additionally,thispersonisresponsi-bleforthedevelopmentofawrittenqualitycontrolplanandforitsimplementation.
Theremustbeacontrollaboratoryatthedisposalofthemanufacturer,andthatlabo-ratorymustbesufficientlyequippedwithstaffandequipmenttobeabletoguaranteeandverifytheconsistencyofthepremixesandthemixedfeedscontainingpremixeswithspecificationspreviouslydefinedbythemanufacturer.Thislaboratorymaybeinternalorexternal.Specificationsthatmustbeguaranteedandverifiedinthelaboratoryinclude:
• type,concentrationandhomogeneityoffeedadditives;• type,concentrationandhomogeneityofallsubstances(includingunwantedsub-
stances)inthemixedfeed;• maximumallowedconcentrationsofunwantedsubstances.
Both internal laboratories that perform analyses for third parties and externallaboratories thatareappointed for thequality controlsmustbeaccreditedandworkaccordingtovalidatedmethods.Internallaboratoriesworkingexclusivelyfortheplantarenotrequiredtobeaccreditedbutmustalsoworkaccordingtovalidatedmethods.Themethodbywhichanalysisresultsareverifiedmustberecorded.
Awrittenqualitycontrolplanmustbedevelopedandimplementedthatincludes,inparticular,thecriticalpointsoftheproductionprocess,theprocedureforsampling(seesection5ofthischapter)andsamplingfrequency,themethodsandfrequenciesoftheanalyses,andthevalidationofthespecificationsofingredients,aswellasproceduresincaseofdisputeregardingthesespecifications.
Criteriafordeterminingthefrequencywithwhichsinglenutritionalsubstances,feedadditivesandunwantedsubstancesmustbeverifiedinclude:
• probabilityofexceedingornotreachingtolerancevalues;• effectonanimalproductioniftolerancevaluesareexceededornotreached;• effectonanimalhealthiftolerancevaluesareexceededornotreached;• probabilityof residues in foodproducts if tolerance valuesareexceededornot
reached.Resultsandmethodsofanalysisofallverifiednutritionalcomponents,feedadditives
andunwantedsubstancesmustberecordedinwriting.Allfeedadditives,premixes,rawmaterialsandsinglecomponentfeeds,intermedi-
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ate products and final products must be characterized using written specifications.Differentiations must be made between specifications that characterize quality (e.g.energy content) and specifications that characterize safety (e.g. content of unwantedsubstances).Specificationsmustbeverifiedbythemanufacturer(forpremixesormixedfeeds)and/orbythesupplier(forfeedadditivesorpremixes).Whenspecificationsareverifiedthroughcertificationorotherdocumentation,therecipientmayalsorequiretestresultswithinanappropriatetimeinterval.
Dispositionmustbedescribedincaseofnon-conformitywiththespecifications.Devi-ancesinqualityanddeviancesinsafetymustbedifferentiated.Incaseofdeviancesinsafety,thefeedmanufacturermustblocktheaffectedproducts.Incaseofdeviancesinquality,thefeedmanufacturermaydecidewhatisdonewiththedeficientproducts,andmustatleastrecord:
• firstmeasuresconductedafteridentificationofthedeviances;• long-termcorrectivemeasures;• verificationoftheefficacyoftheconductedcorrectivemeasures.
Inaddition tosamplescollected for testing,samples fromeverybatchofpremixesandmixedfeedsmustberetainedandstoredinamountsdefinedbythemanufacturer’sprotocolstoenabletracebackofeachproduct.Samplesfromeveryidentifiedproduc-tionsector (continuousproduction)or fromappropriate time intervals (exclusivepro-ductionforownneeds)mustbecollected.Thesesamplesmustbesealedandlabelledsoastobeeasilyidentifiable.Storageconditionsmustpreventabnormalchangestothesample’scompositionandotheradverseeffects,andsamplesmustbeavailableforthecompetentauthoritiesforacertainspecifiedamountoftime,forexamplethreemonthspastexpirydate.
Theprocedure forcollectingandretaining thesesamplesshouldbe inaccordancewith these procedures for other samples (as described in section 5 of this chapter).Additionally,thefollowingpointsmustbeconsidered:
• thesamplesmustbeatleast250grams;• everysamplemusthaveitsoriginallabelandtraceabilitymustbeguaranteed;• thestorageroomsmustbedry,notexposedtoheat,andsafefrompests.
2.�. StorageMaterialsshouldbestoredaccordingtoawrittenplantspecificstorageconcept,whichshouldbemadeavailabletocompanypersonnel.Rawmaterialscontaininghighlevelsof unwanted substances or materials that are destined for detoxification, as well aspremixesandmixedfeedsthatcomplywithspecifications,mustbestoredinappropri-atecontainersorroomsthathavebeenconstructedandmaintainedinsuchawaythatgoodstorageconditionsareguaranteed.
Storageconditionsmustnotproducenegativechangestoquality(e.g.heating,gen-erationofcondensation)duringstorage.Measurestopreventgenerationofcondensa-tionare:
• storingsufficientamountofdryproducts;• coolingandaircirculation;• circulatinggrains.• avoidingdirectsunlightandindirectheat(e.g.viaexposedoutsidewalls).
Contamination of stored products must be prevented by avoiding use of damagedcontainersorstoragerooms,orofdamagedlids,slidersandaircirculationsystems.
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Duringcleaningandmaintenance,allstorageroomsandcontainersmustbecheckedfordamage,especiallyifstorageroomsarealsousedforotherpurposes.
Storageroomsandcontainersmustbeclosedwheneverpossible,andonlypersonsauthorizedbythemanufacturershouldhaveaccess.Thisisespeciallyapplicablewhenproductsarestoredinfreelyaccessibleareasontheplantgroundsorinareasoutsidetheplantgrounds.
Measuresmustbetakentoavoidaccessbyrodentsandotherpestsand,ifnecessary,appropriate eradication protocols must be implemented. Products must be stored insuchawaythattheyareeasytoidentifyandmisidentificationand/orcrosscontamina-tionbetweendifferentproductsisexcluded.
Theconceptshoulddescribehowandwherewhichproductsarestored toexcludemisidentificationorcrosscontaminationbetweendifferentproducts.Ifaplantmanufac-turesand/orstoresmultiplecategoriesoflivestockfeedorisotherwisestoringanimalmaterialsprohibitedforlivestock,thenthosefeedsormaterialsprohibitedforcertaincategories of animals must be clearly identified and must be stored separately fromnon-prohibitedfeedstoreducetheriskofcrosscontamination.Clearidentificationofstoredproductsmeans:
• Forfinalproducts: identificationofcontainerswithappropriatelabelsaccordingtoinstructionsfordeclarationoruniqueidentificationofproductsandsilosthatallowfullbacktracingwithintheoperatingsystemofafeedplant.
• Forrawmaterials,feedadditivesandpremixes:labellingonbagsandcontainersorplantspecificcodes,withbulkstorageentriesinspecificsilosorspecificationsontheoverallsilooperatingsystemorplantspecificcodes.
3. DOCUmENTATION AND DATAThe manufacturer must have a documentation system at its disposal to define andcontrolcriticalpoints in theproductionprocessesand todevelopand implement thequalitycontrolplan.Themanufacturermustmaintaincompleterecordsoftheappropri-ateauditsandothercontrols.Theserecordsmustbestoredsothatthehistoryofeachproducedbatchcanbebacktracedandthattheresponsiblepersoncanbeidentifiedifcomplaintsariseafterdistribution.
Themanufacturermustdocumentthecorrectimplementationofalldefinedpreventivemeasures.Forthispurposeadocumentationprotocolmustbecreatedwhichatmini-mumdescribesallspecificationsandrecordsforcompletetraceability(seebelow),theperson(s)responsibleforthefilingandarchivingofdocuments,theplaceatwhichrecordsarefiledandarchivedandthedurationoffilinganddurationofstorageofrecords.
Atminimum,thefollowingprotocolsandrecordsmustbeavailable:• specificproductionflowchartandcurrentprocessoverviewfortheplant;• analysisofpossiblecarryoverbetweenindividualbatches;• guidelinesforcleaningandmaintenanceoftheworkingarea;• guidelinesforcleaningandmaintenanceofproductionequipment;• preventiveandactivepesteradicationplans;• accreditationofexternallaboratory;• accreditation of internal laboratory (and validation of any methods that are not
includedintheaccreditation);• methodsfortheverificationoftheresultsfromanalyses;• samplingprocedureandprotocols;
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• methodsofanalyses;• frequencyoftherequiredanalyses;• specificationsoftheindividualproductsproducedinthefeedplant (e.g.nutritional);• dispositionprotocolsforproductsthatdonotcomplywiththespecifications;• guidelinesregardingsamplingandstorageofretainedsamples;• guidelinesregardingsamplingandstorageofstoredproducts,includingpreven-
tivemeasurestoavoidgenerationofcondensation;• overviewofrequireddocumentation;• deliveryreceipts,invoices,batchrecords;• checklistforrecallaction;• organizationofproxies;• organizationchart;• jobdescriptionsformanagementandotherpositions.
Inorder toassure the reliable trackingand tracingofproducts, the followingdatashouldbemaintainedwithinthemanufacturer’sdocumentationsystem.
Forallfeedcomponentspurchased:thetype,manufacturer’sbatchnumberandpro-ductiondate,volumedelivered,anddeliverydateoftheproduct,aswellasthenameandaddressof eachsupplier, including thedelivery receiptor invoice indicating thisinformation.
Forallmaterialsproduced:thetype,originalbatchnumber,andvolumeofallcom-ponentsusedand,forcomponentsnotproducedinternally,thenamesandaddressesofsuppliersandallinformationlistedformaterialspurchased(above),aswellasthetype,productiondateandvolumeproduced.
For feedadditivesandpremixesused in furtherproduction internally: the typeandoriginalbatchnumber,thevolumeusedand,fortheresultingproduct,thetype,produc-tiondate, resultingbatchnumber (including the internalbatch record indicating thisinformation) and, in case of continuous production, the point of introduction into theproductionline.
Forfeedadditives,premixes,andmixedfeedssold:thetype,batchnumber,volume,anddeliverydateof theproduct,aswellas thenameandaddressof the receiveroftheproduct(traderorenduser),includingthedeliveryreceiptorinvoiceindicatingthisinformation.
4. COmpLAINTS AND pRODUCT RECALLEachlegitimateandillegitimatenegativecommentfromacustomermustbeconsid-eredacomplaintandacausemustbesought for theproblemwith theproduct.Themanufacturermustrecordandverifycomplaintssystematically,includingatminimumthefollowingpoints:
• personfilingthecomplaint;• productthatisthesubjectofthecomplaint(includingbatchnumber,production
ordeliverydate),problemdescription,entrydateofcomplaintandsignatureofthepersonwhohasacceptedthecomplaint;
• immediatecorrectivemeasuresoractiontaken;• re-auditinwhichtheeffectivenessoftheconductedcorrectivemeasuresare verified;• finalaudit.
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Themanufacturermustbeabletoimplementasystematicevaluationquicklysothatproductscanberecalledifindicated.Documentsreviewedmustinclude:
• productionorbatchrecords;• deliveryreceiptsandinvoices;• analysisreportsandcertificates;• cleaningandmaintenancerecords;• recordsofproperstorageofproducts;• recordsoftestequipmentchecks(e.g.verificationofscales,temperaturemeas-
ures,humiditymeasures);• standardrecipesandhandlingprotocols(dateofuse,dateofwithdrawal);• productflowprotocolsforstartingmaterials,feedadditivesandpremixes.
If a product is recalled, it is important to be able to quickly and specifically iden-tifyaffectedcustomers.Themethod for identificationofaffectedcustomersmustbedefinedinwriting,andachecklistdeveloped.Thechecklistmustalsoincludehowtherecalledproductswillbeprocessed.Themanufacturermustmaintainwrittenrecordsofthedestinationofrecalledproducts.Beforedecisionscanbemaderegardingfutureuseorresaleoftheseproducts,theymustundergoathoroughqualitycheck.
�. SAmpLE COLLECTIONThecollectionofappropriatesamplesof feed ingredientsor finishedcompound feedis an important aspect of feed control, both for domestically produced and importedfeeds.The individualsamplescollectedmaythenbetestedusingdifferent laboratoryanalyses,inorderto:
• detectprohibitedcomponents,particularlythoseofanimalorigin;• verifythatingredients,pesticides,drugsandmedicationsareusedproperly;• determinethatthefeedisofcomposition,quantityorqualityasrepresentedbythe
label;• havebankedsamplesavailablefortraceback.
Sampling and testing may be carried out in the context of official feed control orwithinthequalityassuranceprogrammeofafeedproductionplant,andresultsofthetestingmayserveasabasisorjustificationfordefendingagainstlegalactionsorprov-ingliability.Theverificationofproductionorimportdocumentsmustbedoneinparallelwiththesamplecollection.Whenthesamplecollectioniscarriedoutbyafeedinspec-tor,hemustassurethatanemployeeoftheplantispresentduringhisvisit.
The sampling protocol(s) for both feed plants and for governmental control pro-grammemustbeavailableinawrittenform.Theprotocolmustallowforsamplingatregularintervals,andassurethatthesamplestakenarehomogeneousandrepresenta-tiveoftheentirebatch.Theprotocolincludesatleastthefollowingdetails:
• devicewithwhichthesamplesaretaken;• methodofcollection;• timingofsamplecollection(momentinproduction);• numberofsamplesperbatch;• distributionofthesamples;• typeofproductforwhichtheprocedureisvalid;• frequencyofcollection;• frequencyofaudits.
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tionstartswiththeshippingdocumentsforthereceiptofrawmaterials.Assuringprop-eringredientidentityandqualityisimportantforitsappropriateuseinfeedproduction.Alreadyatthisstage,samplingandtestingcanrevealcomminglingorcrosscontamina-tionwithprohibitedcomponentsofanimaloriginduringtransport.Representativesam-plesshouldbetakenbeforeunloadingandretainedforseveralmonthsafterthefeedinwhichtheingredientisusedismanufacturedanddeliveredtothebuyer(aspartoftheoverallqualityassuranceprogramme).Theprocessforsamplingofrawmaterialsandfinishedproductsissimilar,andmustincludebagged,bulk,andliquidfeed.
Theamountofmaterialtobecollectedeachtimeforeachpurpose(e.g.importcon-trol,feedplantinspection)mustbedeterminedandwrittenintherespectiveprotocol.Generally,atleastfivetotenseparatesamplesofeachdifferentingredientandfinishedfeedshouldbecollectedeachtime,tototalbetween500to1000gramsofeachmate-rial.Althoughit isoftendifficult,aneffortshouldbemadetoobtainasamplethat isrepresentativeoftheentirebatchofmaterial.Forexample,toattempttosamplefeedsfromdifferenttimepointsduringtheproductionofthebatch,bagsshouldbeselectedforsamplingthathavebeenstoredinslightlydifferentlocations, i.e.fivebagsshouldnotbeselectedthatarestackedrightnexttoeachother.
Forbaggedproducts,itmustfirstbedeterminedhowmanybagsmustbesampled(at approximately 100 grams sampled per bag) to achieve the final sample volumerequiredbytheprotocol.Then,astandardslotterbagtrier(samplingdevice)isinsertedintheuppersectionofthebag(slotinthedownwardposition).Theslotofthesampleprobemustbelargerthanthelargestparticleofthefeedbeingsampled.Thesampleistakenbyrotatingthetrieruntiltheslotisontheuppersideofthetrier,whichisthenremoved.
Forbulkfeed,thesamplecollection isbestcarriedoutwhile loadingorunloading,i.e.atrailcars,trucksortrailers.Withastreamcutter,aminimumof10cutsatequalintervalsaretakentoprovideapproximatelyonekgtotalsample.Withstationarybulkfeed(generallyinavehicle),onlyalimitedaccessispossible.Dependingontheacces-sible surface of the feed, a minimum of 10 probe samples are taken from differentcompartments.
Forliquidingredients,itisbesttoobtainsamplesatperiodicintervalsduringunload-ing. It is advisable to discard the first several litres of material before sampling, toaccountforanysolidsorcontaminantsthatmayhavecollectedinthetank.
Thepersonresponsible forsamplecollectionmustbecareful topreventanycon-tamination during the process. Separate equipment must be used for each sample,samplessealedindividually (e.g.usingbagtriers),andgeneralhygienerules(e.g.forclothingandhandlingoffeed)mustberespectedduringtheprocess.
Atthecollectionsite,thesamplesmaybeassessedfortheircolour,texture,odourandmoisturecontent.Thepresenceofforeignobjectsmaybeassessedandthetem-peraturedeterminedforliquidfatsandmolasses.Thedetailedlabelofthefeedingre-dient/finishedfeedshouldbeattachedtoeachsample.Furtheranalysesaregenerallyperformedinthelaboratory.
�. SUmmARy OF TSE-RELEvANT CONCEpTS• The overall quality assurance systems in feed plants, including separation of
productionlines,areimportanttominimizetheriskforcrosscontaminationwithprohibitedmaterials.
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• The exact implementation requirements for separation of materials will bedependentonthespecificfeedbansinplace.
• Samplecollectionfordetectionofprohibitedmaterialofanimaloriginisimpor-tantforimportcontrolaswellasforfeedplantqualitycontrol.Itmustbedoneatregularintervalsandincluderawingredientsaswellasfinishedproducts.
�. REFERENCESALp(Agroscope Liebefeld-posieux).2004.http://www.alp.admin.ch/
FAO. 2007. Management of transmissible spongiform encephalopathies in meat production.Course manual, Project Capacity Building for Surveillance and Prevention of BSE and OtherZoonoticDiseases.Rome
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LABORATORy ANALySIS FOR THE DETECTION OF pROHIBITED mATERIALS IN LIvESTOCk FEED
1. GENERAL CONCEpTSImplementationofaneffectivefeedbanisacrucialcomponentofanynationalBSEcon-trolprogram.Inordertoeffectivelyenforceanyfeedbaninplace,representativesam-plesfrombothimportedanddomesticallyproducedfeedsmustberoutinelycollectedandtested(Gizzietal.,2003).Samplecollectioniscoveredinthe“Qualityassuranceinfeed-producingplants”chapterinthiscoursemanual.
Unfortunately,itisnotpossibletodirectlydetectprionsinsamplesoffeedandfeedcomponents. Therefore, laboratory methods must focus on detecting the presence(intentionalorinadvertent)ofprohibitedmaterials,primarilyMBM.Becauseofthedif-ferences in thescopeof feedbans implemented indifferentcountries, the testusedmustbeappropriatetothespecificresultrequired.
Forexample, invariouscountries fishmeal,poultrymeal,and/orpuremeals fromnon-ruminant animal species (e.g. equine, porcine) may still be allowed for feedingof pigs, fish and/or poultry, as well as ruminants in some cases. In other countries,all animal proteins are banned for all food-producing animals. Therefore, the mostappropriatetestforaparticularcountrymightbeonethatdetectsanyanimalmaterial(including fish),any terrestrialanimalprotein (i.e.poultryandmammals),anymam-malian material or any ruminant material. If all intra-species feeding is banned (asintheEU;EU,2002)1, thetestwillneedtodistinguishamongmaterial fromdifferentmammalianspecies.Moreover,thepresenceofanimalmaterialinadvertentlyincludedinfeeds(suchasrodentsandbirds)mustbeconsidered.AlthoughthismaterialisnotconsideredtoposeaTSE-relatedrisk,itspresencemightaffectthevalidityofthetestresultaswellasindicateotherproblemswiththequalityandsafetyofthefeed.
In addition, a quantitative test method may or may not be required depending onwhetherthefeedbaninacountryincludesanallowablelevelofaprohibitedmaterial,orwhetheranydetectableprohibitedmaterialisunacceptable.
Furthermore,different laboratory testsdiffer in theirability todistinguishmaterialthathasundergoneprocessing.Forexample,theMBMproducedbyrenderingatspecif-icconditionsofheat,pressureandtimemaynolongertestpositiveformaterialofinter-est(usuallyproteinorDNA)whencertaintestsareused.Therefore,bothwhenchoosingthetestingmethodandwheninterpretingthetestresults,theprocessingconditions(orpossibleconditions)forimportedanddomesticMBMmustbetakenintoaccount.
For example in the EU, with the exception of the intra-species feed ban, currentlegislation only requires distinction between material from fish and material fromterrestrial animals for in feed for most livestock. In addition, all rendering plants intheEUstatesshouldbeprocessingatstandardparameters (133ºC/3bar/20minutes;seethe“Renderingofanimalby-products”chapter in thiscoursemanual for further
1 Theintra-speciesbanrequiresdeterminationofthespeciesoforiginforallfeedcomponentsexceptbloodandmilk,butwillonlyberelevantifandwhenthecurrentmammaliantolivestockbanislifted(EU,2002).
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discussion).Therefore,testsmustbeabletodistinguishbetweenfishmealandMBMprocessedundertheseconditions.Noquantificationisrequired,asintheEUdetectionofanyprohibitedmaterialinasamplemeansthatfeeddoesnotcomplywiththefeedban.Therefore, testsor testingprotocols forall feedmaterialsproducedboth in theEUstatesandimportedfromothercountriesintotheEUmustbeabletoappropriatelyaddressthesequestions.
2. AvAILABLE TEST mETHODSDifferenttestsmakeuseofdifferentapproachesfordetectionofprohibitedmaterialsinfeed.Inopticalmicroscopy,animaltissuessuchasbones,musclefibres,hairs,andfeathersaredirectlyidentified.Withothermethods,variousanimalproteins,peptides,lipids,DNA,volatilematerialsorspecificorganicmoleculesareidentified.Theprimarytestmethodscurrentlyusedaredescribedinthefollowingsections.
2.1. Optical microscopyOpticalmicroscopy(OM)isthedirectidentificationofanimaltissuesbytypicalphysicalstructure. It involvesconcentrating thematerialsbybothsedimentationand flotationand thenevaluating thematdifferentmagnificationswithboth thestereomicroscopeand thecompoundmicroscope (Plates1-5).Thesedimentcontainsmineralparticlesincluding bones and teeth, and the floatation contains organic particles, which aremainlyplantproductsbutincludemeatparticlesandfeathers.
Technically,theOMmethodologyisrelativelysimple(EU,2003).However,inpractice,OM technicians must have a high level of expertise that only comes from extensiveexperienceinobservingMBMsamplesunderthemicroscope.
Sedimentation/flotation: About 10 grams of feed material are first dissolved in anorganicsolvent(tetrachlorehylene)toconcentratethemineralsinthesedimentandtheorganiccomponentsintheflotation.Thisseparatesthematerialasfollows:
Sediment: Minerals,salts,phosphate,magnesium Animalcomponents:terrestrialanimalbonefragments,fishbone fragments,scales,teethFlotation: Plantmaterial Animalcomponents:meatparticles(musclefibres),feathers,hairsThen,bysievingandweighing,threefractionsofdifferentparticlediameter(>1mm,
between1and0.35mm,and<0.35mm)areobtained.Observationwiththestereomicroscope:Preparationsofboththesedimentandthe
flotationaremade from the fractionofparticlesgreater than1mmdiameter.Theselargeparticlesofbonefragments(sediment)ormeatparticles(flotation)maybevisual-izedinthestereomicroscopeatamagnificationof50x.
Observationwiththecompoundmicroscope:Thesedimentispreparedwithaclear-ing agent (phenoglycerin) and the flotation is treated with potassium iodide (to staintheproteinsorange-yellow).Thepreparationsarethenobservedatamagnificationof50-400x with the compound microscope. Generally, three preparations are screened,onepreparationofthe<0.35mmfractionandtwopreparationsofthefractionbetween1mmand0.35mm.
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plate 1
Terrestrialanimal(mammalorbird)bonefragmentinsedimentationfractionofcompoundfeedsample,asseenwiththestereomicroscope.Magnification50x,particlesize>0.315mm
plate 3
Fishbonefragmentinsedimentationfractionofcompoundfeedsample,asseenwiththecompoundmicroscope.Magnification100x,particlesize<0.315mm
plate 4
Musclefragment(fishorterrestrialanimal)inflotationfractionofcompoundfeedsample,asseenwiththecompoundmicroscope.Magnification400x,particlesize<0.315mm
plate �
Featherfragmentinflotationfractionofcompoundfeedsample,asseenwiththecompoundmicroscope.Magnification400x,particlesize<0.315mm
plate 2
Terrestrialanimal(mammalorbird)bonefragmentinsedimentationfractionofcompoundfeedsample,asseenwiththecompoundmicroscope.Magnification100x,particlesize<0.315mm
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2.2. ImmunoassayImmunoassayisamethodtoidentifyaspecificproteininasample.Itinvolvesextrac-tionoftheprotein,reactionoftheproteinofinterestwithaspecificantibodyandthenamplificationandvisualizationoftheresponsesignal.
However,becausemanymaterialstobetestedhaveundergoneprocessing, immu-noassaysmustovercometheproblemofmaintainingtestsensitivityandspecificity inthefaceofthedegradationofproteinsthatoccursduringheating.Furthermore,evenwhennot fullydegraded, theconformationofproteinsoftenchangeswithheat treat-ment. Therefore, the immunoassay must employ antibodies that detect either heatstableantigenicsitesorantigenicsitesonheatstableproteins,i.e.thosethatremainaftertheapplicationofheattreatmentand/orotherappropriateprocessingparameters.Therefore, a parallel application of the immunoassay methodology is to control andaudittheadequacyofprocessingparametersattherenderingplantbymeasuringthepresenceordegradationofvariousproteins(Pallaronietal.,2001).
ThefirstmethoddevelopedfordetectionofMBMusingmolecularbiologytechniqueswasan immunoassay fordetectionofruminantproteins inrenderedmaterialheatedtogreaterthan130ºC(Ansfield,1994),andanimprovedimmunoassayfordetectionofruminantandporcineproteinsheatedtogreaterthan130ºCat2.7bar incompoundanimal feeds was later described (Ansfield et al., 2000). However, the usefulnessof these immunoassays was somewhat restricted by their tedious protocols whichrequiredperformanceinspecializedlaboratories.
Colour-linked antibody (1) bound to antibody pre-bound on strip = coloured line
Protein
Au
Vial
Absorbent pad
Test line
Sample
Filter pad
Gold pad
Membrane
Control line
Colour-linked antibody (1) unreacted
Colour-linked antibody (1) bound to ruminant protein (if present), bound to antibody pre-bound on strip = coloured line
Au
Au
Scheme of a strip test
FigUre 1
Basic schematic of a lateral flow immunochromatographic assay (strip test) for detection of specific proteins in feed
Source:OliviereFumière,WalloonAgriculturalResearchCentre,Gembloux,Belgium.
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Morerecently,anewtypeofcommercialimmunoassayhasbeendeveloped,theso-called“striptest”(Figure1),mostcommonlyusedtoidentifyruminantprotein.Thesesingle-steplateralflowimmunochromatographicassaysaresimpletohandleandallowthetestingofmanysamples inarelativelyshort time.Mostof thesetestsdetectthepresenceofTroponin I (aheatstableruminantmuscleprotein) in thesample.Theseimmunoassaysarenotquantitative,andgiveeitherapositiveornegativeresultwithadetectionlimitat1%to5%forMBMthathasbeenrenderedatthestandardprocessingparameters(133ºC/20min/3bar).
2.3. Lateral flow immunochromatographic assays Thetestprocedureofthelateralflowimmunochromatographicassays(striptests)nor-mallyincludesweighingoutofapproximately10gramsthesample,addingextractionsolution,shortheatingofthesampleinboilingwaterorwashing(dependingonassay),placing the test strip into the sample tube and reading of the results within severalminutes.
The strips have two possible visualization zones: A reaction line that appears onlyif ruminant protein is present and a control line that forms to validate that the stripisworkingproperly.Specific testproceduresdiffer for thedifferent tests,andfurtherdetailsareavailablefromthemanufacturers(Table1).
2.4. polymerase chain reaction Polymerasechainreaction(PCR)isamethodtoidentifyspecificDNAinasample.ItinvolvesgrindingofthesampleandextractionoftheDNA,followedbyamplificationofthoseDNAsequencesthatarespecificallyof interestandvisualizationof theampli-fiedDNAfragments(Brambillaetal.,2004;Kingombeetal.,2001;Matsunagaetal.,1999).
2.�. Near infrared spectrographyNearinfraredspectrography(NIRS)isamethodtoidentifyspectrographicvibrationsofgroupsoforganicmolecules(e.g.O-H,C-H,N-H)indicatingspecificmaterialsofinter-est.Itinvolvesinitialcalibrationandvalidationofthesystem,preparationandirradiationofthesample,andanalysisoftheanswerspectrausingspecificmathematicalequa-tions(Murrayetal.,2004).
2.�. Near infrared microscopy Near infraredmicroscopy (NIRM) isalsoaspectrographicmethod to identifyspecificisolatedparticles.Itinvolvesconcentrationofbonematerialbysedimentation(similartoOM),irradiationandanalysisofapurespectrumforeachparticle,andclassification
TABLE 1. Selected lateral flow immunochromatographic assays, including manufacturer information
Company web site Test name
NEOGEN®Corporation www.neogen.com ReVeat®
StrategicDiagnosticsInc. www.sdix.com FeedCheckTM
CIBITestGMBH&Co.KG www.cibitest.de FLORIDA
ELISATechnologies,Inc. www.elisa-tek.com MELISA-TEKTMRuminantKit
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of theparticles. In this test,mineralsshownovibrationspectra (Murrayetal.,2004:Baetenetal.,2004).
2.�. Near infrared camera Nearinfraredcamera(NIRC)issimilartotheNIRMbutfaster,asitcananalyse500par-ticlesinfiveminutes.Theequipmentisexpensive,andthereisahighcostperanalysis(Baetenetal.,2004).
2.�. High performance liquid chromatographyHighperformanceliquidchromatography(HPLC)isamethodtodetectspecificdipep-tides that indicate thepresenceofmuscle tissue (e.g.carnosine).However,with thismethoditisnotpossibletodifferentiatebetweenmusclefromterrestrialanimalsandthatfromfish.ThistestmethodisdescribedbySchönherr(2002).
2.�. Electronic noseElectronicnoseisarecentapproachforscreeningrawmaterialsbyodour,butisnotyetcommonlyused.ThistestmethodisdescribedbyCampagnolietal.(2004).
Nointernationalstandardsexistforperformingthesetests,asdifferentinternationalworkinggroupshavesettheirownstandardsforthedifferentmethods.Forexample,theEuropeanFeedMicroscopistsWorkingGroup(IAG)setsstandardsforOM,andtheEUprojectonmethodstodetectMBM(Stratfeed,2004)hassetstandardsforOM,PCR,NIRS,andNIRM.
3. COmpARISON OF TESTSEachmethodhasadvantagesanddisadvantages(Table2:VonHolstandBoix,2004).OMisbasedprimarilyonthedetectionofbonematerialandisnotaffectedbytheprocess-ingparametersofthesample.InOM,terrestrialanimalbones(Plates1and2)canbedistinguishedfromfishbones(Plate3)inthesedimentationfraction,butbonematerialfrommammalsandpoultrycannotbeseparated.ThisalsomeansthatwithOMitcan-notbedeterminedifbonematerialisfromrodentsorbirdsthatmaybeinadvertentlypresent in feed components. Muscle (Plate 4) in the flotation indicates the presenceofanimalmaterial (terrestrialanimalorfish) inthesample,buttheorigincannotbedistinguishedmorespecifically.The identificationof feathers (Plate5) in the flotationis indicativeof thepresenceofpoultryorotheravianmaterial,but feathersmustbedistinguishedfromplantmaterial,whichmaylooksimilar.
The PCR is species specific, but is also sensitive to contamination and interferingingredients thatmayaffect thevalidityof the result. Itmaybeappropriateasacon-firmatorymethod.Overthepastfewyears,bothmolecularbiologicalmethods(PCRandimmunoassay)haveimprovedintheirabilitytodetectheat-treatedMBM,asthetestsnowutilizethedetectionofveryshortDNAtargetsequencesandmorestableproteinfragments,respectively.
A relatively high number of samples can be processed in a short time with bothimmunoassay and NIRS. Therefore, these could be appropriate screening methods,especiallyastheydonotrequiretoxicreagents.However,althoughimmunoassayhasaverylowleveloffalsenegativeresults,theybothhaverelativelylowsensitivities,whichisnotoptimalforscreeningtests.
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TABLE 2. Comparison of characteristics of the main testing methods
Test characteristic Optical microscopy pCR1 Immunoassay NIRS2 NIRm3
Terrestrialanimal/fishdifferentiated yes yes yes yes/no yes
Speciesidentificationpossible no yes yes no no
Limitofdetection(%offeed) <0.1% ~0.5% ~1% 3-5% <0.1%
Samplesizerequired(ingrams) 5-20g 0.1-1g 10g 5-100g 0.2-10g
Falsenegativeandpositiverate verylow low verylow high verylow
Interferencefromallowedingredients (milk,blood) noproblem problem problem noproblem noproblem
Interferencebyheat/ processing(MBM) noproblem someproblem someproblem noproblem noproblem
Matrixdependent no yes no yes no
Particlesize noproblem noproblem noproblem noproblem problem
Riskoferroneousresult duetocontamination verylow high low low low
Quantitationpossible no no no yes yes
Reagenttoxicity yes yes no no yes
Requiredexpertiseofanalyst high high low low low
Numberofpossiblesamples/day/analyst ~10 ~10 100-200 100-200 3-5
Existingfacilitiesusable yes yes yes yes no
Initialcostofinstrumentation average average low average average
Costofanalysispersample average average low low average
Note:1 Polymerasechainreaction2 Nearinfraredspectrography3 NearinfraredmicroscopySource:adaptedfromVonHolstandBoix(2004)
NIRMhasahighsensitivityandissimilartoOMwiththeadvantagethatitcanquanti-fythematerialinthesample.TheNIRcameraisexpensive,butalsogivesaquantitativeresult.Besidesbeingquantitative,bothhavetheadvantageofbeingabletodeterminedifferentingredientsinoneanalysis.
Giventhesecharacteristicsoftests,thedecisiononwhattesttousemustpracticallyconsider:
• thebaninplace(andthereforethequestiontobeanswered);• thenumberofsamplestobetested;• theequipment,infrastructureandtechnicalpersonnelavailable.
4. SUmmARy OF TSE-RELEvANT CONCEpTS• Laboratorytestingofdomesticandimportedfeedsandfeedcomponentstoiden-
tifyprohibitedmaterialsisnecessaryforeffectiveimplementationoffeedbans.• Testsdifferintheextenttowhichtheycanidentifythecategoryofanimalaprotein
isderivedfrom.• The method(s) chosen must be able to provide information appropriate to the
specificfeedbanandothermeasuresinplace.
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�. REFERENCES Ansfield m. 1994. Production of a sensitive immunoassay for detection of ruminant proteins in
renderedanimalmaterialheatedto130ºC.FoodandAgriculturalImmunology6,419-433
Ansfield m, Reaney SD, Jackman R.2000.Productionofasensitive immunoassay fordetection
of ruminant and porcine proteins, heated to >130 degrees C at 2.7 bar, in compound animal
feedstuffs.FoodandAgriculturalImmunology12,273-284
Baeten v, michotte AR, Fernandez pierna J, Fissiaux I, Fumière O, Berben G, Dardenne p. 2004.
Review of the possibilities offered by the near infrared microscope (NIRM) and near infrared
camera(NIRCamera)forthedetectionofMBM.StratfeedSymposiumFoodandfeedsafetyinthecontextofpriondiseases.Namur,Belgium.AbstractL15
Brambilla G, Aarts H, Berben G, vaccari G.2004.PCRastooltoidentifytaxon-specificprocessed
animalproteins.StratfeedSymposium Foodand feedsafety in thecontextofpriondiseases.
Namur,Belgium.AbstractL13
Campagnoli A, pinotti L, Tognon G, Cheli F, Baldi A, Dell’Orto v. 2004. Potential application of
electronic nose in processed animal proteins (PAP) detection in feedstuffs. Biotechnol AgronSocEnviron8(4),p.253-255
EU (European Union). 2002. EC Regulation No. 1774/2002 laying down health rules concerning
animalby-productsnotintendedforhumanconsumption.http://europa.eu.int/eur-lex/pri/en/oj/
dat/2002/l_273/l_27320021010en00010095.pdf
EU. 2003. Directive 2003/126/EC on the analytical method for determination of constituents of
animaloriginfortheofficialcontrollingoffeedstuffs(plusannex).http://europa.eu.int/eur-lex/
pri/en/oj/dat/2003/l_339/l_33920031224en00780084.pdf
Gizzi G, van Raamsdonk Lw, Baeten v, murray I, Berben G, Brambilla G, von Holst C.2003.An
overview of tests for animal tissues in feeds applied in response to public health concerns
regardingbovinespongiformencephalopathy.RevscitechOffintEpiz22,311-331
kingombe CIB, Luthi E, Schlosser H, Howald D, kuhn m, Jemmi T.2001.APCRbased test for
species specific determination of heat treatment conditions of animal meals as an effective
prophylacticmethodforbovinespongiformencephalopathy.MeatScience57,35-41
matsunaga T, Chikkuni k, Tanabe R, muroya S, Shibata k, yamada J, Shinmura y.1999.Aquick
andsimplemethodfortheidentificationofmeatspeciesandmeatproductsbyPCRassay.MeatScience.51,143-148
murray I, Garrido-varo A, pérez-marín D, Dardenne p, Baeten v, Termes S, Frankhuizen R.2004.
Application of near infrared spectroscopy (NIRS) to detection of mammalian meat and bone
meal(MBM)infeeds.AbstractL14.StratfeedSymposiumFoodandfeedsafetyinthecontextofpriondiseases.Namur,Belgium
pallaroni L Bjorklund E, von Holst C, Unglaub w. 2001. Determination of rendering plant
sterilizationconditionsusingacommerciallyavailableELISAtestkitdevelopedfordetectionof
cookedbeef;AOACInternational84(6),1884-1890
Schönherr J.2002.Analysisofproductsofanimalorigininfeedsbydeterminationofcarnosineand
relateddipeptidesbyhigh-performanceliquidchromatography.JAgricFoodChem50,1945-1950
Stratfeed.2004.http://stratfeed.cra.wallonie.be/Public_Web_site/Home_page/index.cfm
von Holst C, Boix A. 2004. Meat and bone meals in feed: Results from recent interlaboratory
studies for the validationofmethodsand for theevaluationof theproficiencyof laboratories
Abstract L17. Stratfeed Symposium Food and feed safety in the context of prion diseases.
Namur,Belgium
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BSE risk and trade
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BSE RISk AND TRADE IN ANImAL pRODUCTS AND LIvESTOCk FEEDS
1. GENERAL CONCEpTSCurrently,thereisatrendformoreandmorecountriestoparticipateininternationalor regional trade in agricultural products. The economic and quality-of-life benefitsof increased trade, especially for developing countries, can be enormous (WorldBank,2005).However,theriskstoglobalpublicandanimalhealthalsoincreasewithincreasedmovementoftheseproducts.ThespreadofBSEisanexcellentexampleoftheseincreasedrisks.Thischapterpresentsaspectsoftradeinagriculturalproducts,suchasassessmentofBSErisk,availabledataandotherissuesofglobaltrade.
2. THE EFFECTS OF BSE ON GLOBAL TRADEClearly, theworldsupplyofanimalproteinhasbeendisruptedby theappearanceofBSE.Trade inanimalprotein, includingmealsmade fromprocessingofmammalianprotein(e.g.meatandbonemeal/MBM)aswellnon-mammalianprotein(e.g.poultrymeal, fishmeal) isalreadymorerestrictedthan inthepast,andcouldbecomemorerestricted as countries become more aware of risk of BSE and other diseases thatmaybespreadthroughlivestockfeeds.However,aseconomiesgrowandthedemandincreases for meat and other animal products, the demand also increases for high-qualityproteinsformanufactureoflivestockfeeds.Globalizationofmarketscaneasesomeoftheeffectsofthisincreasedproteindemandbutglobaltradealsointroducesnewrisks.Moreover,animalwelfare,environmentalissuesandanincreasedconsumerawarenessoffoodsafetyallmustbeconsideredwhentradinginagriculturalproducts.
Consequently,additionalsourcesofhigh-qualityalternativeproteinwillneed tobeestablished or reconsidered, (as described in the “Protein use in livestock feeding”chapterinthiscoursemanual)andassurancesforthesafetyofnon-prohibitedanimalproteinsourcesimproved.Thiswillincludeassuringfulltraceabilityandstrengtheningof compliance with international regulations, which will require increased technicalcapacity inmanyexportingcountries.Ultimately,allof these factors, inparallelwiththeTSE-relatedfeedbans,willplayaroleinthetypesofproteinsproducedandtradedintheworld.
3. ASSESSING THE RISkS OF BSE IN TRADE Inprinciple,alltradedecisionsmustbebasedonanassessmentoftheexportingcoun-try’sactualriskforaspecificcommodityanddisease,aswellasthedomesticsituation(HeimandMumford, 2005).WTO, through theOIE (the international standardsettingbodyforanimalhealthissues)andtheCodexAlimentarius(theinternationalstandardsettingbodyforfoodsandfeeds),requiresariskassessmenttobemadeanytimeagri-culturaltraderestrictionsareinplacethataremorestringentthantheseinternationalstandards(WTO,1994).Withoutanassessmentscientificallyjustifyingtheirrestrictions,WTO member countries are not in compliance with Agreement on the Application ofSanitaryandPhytosanitaryMeasures.
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Forexample, inmostcases it isnot logical toprohibit importofaproduct fromacountrywhereadiseaseisendemic if thediseaseisalsoendemicdomestically,or ifthedomesticsituationprecludesspreadorestablishmentofthedisease(e.g.aninsect-bornediseaseinacountrywherearequiredvectordoesnotexist,orBSEinahypotheti-calcountrythatraisesnoruminantlivestock).
Similarly,itisnotlogicaltobanproductsfromacountrywhereadiseasehasbeenreported, if the importingcountryhasasimilardomesticrisk (even ifcaseshavenotbeen reported). Therearemanyexamplesof countries implementing importbansorrestrictionsafteratradingpartnerreportsafirstBSEcase,eventhoughtheimportingcountryhasanequivalentBSErisk.ItisalsoclearthatBSEexposureofacountryprob-ablyhappened5-15yearsbeforeanycasesareseen,andthereforeimplementationofbansagainstlong-timetradingpartnersdoesnotnecessarilyaffectcurrentrisk(HeimandMumford,2005). ItmustalsobeconsideredwhetherthereisalargediscrepancybetweenBSEcontrolmeasuresimplementedintheimportingandexportingcountries.
In addition, it is not logical to ban products that pose negligible risk. The OIE hasdeterminedthatmilkandmilkproducts,proteinfreetallow,andcertainotherproductsposenegligiblerisk, irrespectiveof theBSEriskof theexportingcountry (OIE,2005).Debonedbeef(undercertainconditions)canalsobetraded,evenfromcountrieswithariskofBSE(OIE,2005a).Therefore,thereshouldbenorestrictionsonimportingtheseproducts, even when the exporting country has a non-negligible BSE risk. However,restrictionofsomeproductsforhumanconsumption(e.g.processedmeatpies,mincedmeat)fromcountrieswithariskbutinsufficientcontrolmeasures(e.g.noSRMban)canbejustified,asthesecouldposeanimmediatepublichealthrisk.
The impact of all these scenarios on BSE risk through trade would be taken intoaccountthroughtheprocessofnationalriskassessment inconjunctionwithassess-mentsof theriskof importingspecificproducts.Nationalriskassessmentsarecur-rentlyavailableforsomecountries,asdescribedinthe“IntroductiontoTSEsandBSE”chapterinthiscoursemanual.
4. TRADE DATA: QUALITy AND QUANTITy Sufficient valid trade data of high quality for any commodity can be extremely diffi-cult tocollectandcompile.Countriesengaging intradegenerallymaintaintheirownnationalrecordsofimportandexports,althoughthelevelofdetailvariesconsiderably.Examinationofrecordsoftenshowsdiscrepanciesbetweenimportrecordsandexportrecords for a single transaction between two countries, and records of transactionsbetween neighbouring countries may not be even minimally complete. Moreover, nosingle international institution is responsible for compiling these data into a singleglobaldatabase.
Indevelopingcountries, theproblemwith tradedata isoftenaugmented forpoliti-calorinfrastructuralreasons,orboth.Manydevelopingcountriesstilldonothaveanadequaterecord-keepingsystemintheagriculturalsector.Indevelopingcountries(aswellasinmanydevelopedcountries)muchoftheavailableagriculturaldataareincom-pleteintermsofcommoditiesincluded,rangeofvariablesincluded,andgeographicalcoverageofthecountry.Furthermore,evenwhendataareavailable,theirreliabilitymaybequestionable.
Whenspreadof infectiousdiseases isconsidered, trackingof importsandexportsbecomescrucial. In thecaseofBSE,whichcarriespublicandanimalhealthconse-
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quences,theimportofriskyproductsmustbeexaminedtoevaluateanationalexposurerisk for importing as well as exporting countries, as described above. Unfortunately,duetothelongincubationperiodofthisdisease,dataonimportsbeginninginthemid-1980sthroughtodaymustbeavailableforexamination.
4.1. Data sourcesFAOisonesourceoftradedata.FAOcompilesinformationonvariousaspectsoffoodand agriculture from member countries throughout the world to support their pro-grammes and activities. The data are analysed and interpreted and made generallyavailable (FAOSTAT, 2004). Data compiled by FAO that are relevant to this discussionincludeagriculturalproduction,agricultureandfoodtrade,foodaidandexportsofcere-alsbysourceanddestination.
FAO collects its data through questionnaires sent annually to member countries,accessingwebsitesofthecountries,nationalandinternationalpublications,countryvis-itsmadebyFAOstatisticians,andreportsbyrepresentativesinmembercountries.Intheabsenceofreliablesourcesorwheninformationisnotavailable,figuresareestimatedonthebasisof tradedata fromtradingpartners. In thecaseofentirelymissingdata,statisticiansestimatecertaindatapointsifotherparametersaresufficientlyavailable.
Inaddition to thesedata, somedata fromEUmembercountriesareobtainedandcompiledthroughEurostat(2004).TheUnitedNationsStatisticsDivision(UN,2004)hasextensivepublicationsnotonlyrelatedtotradestatistics,butalsoregardingothertradestandardsandissues.Insomecases,officialtradedatacanbesupplementedwithtradeinformationanddatafromothernationalorinternationalagenciesororganizations,aswellasfromunofficialsources.
4.2. problems encountered in gathering and interpreting trade dataSystemsfortradereporting.Countriesmayreportdataonimportsandexportsindiffer-entways.Forexample,theymayhavedifferentsystemstodescribeimportedcommodi-ties used for domestic consumption and those re-exported to other countries. Mostcountriesreportgeneraltradedata,whichdonotdiscriminatebetweengoodsusedandgoodsre-exportedwithoutenteringthecountry,i.e.exportsfromcustomswarehousesand freezonesorports.Thisdistinction is important inconsideringwhetheracom-modity (suchasMBM)hasbeenusedwithinacountryorexportedonward toa thirdcountry,butdependingonthesystemusedtheinformationmaynotbeascertainable.Inaddition,itmaynotbeascertainablewhetheraparticularimportcontainedmaterialproducedonlyintheexportingcountry,oralsoincludedproductsoriginatingelsewhere.Consequently,itisdifficulttoevaluatetheBSEriskforre-exportedproducts,especiallythosethathavebeenheldforlongperiodspriortoshipment.
Classification and definitions. Additional problems regarding trade data are thediscrepanciesthatexistinclassificationanddefinitionoftradedcommodities(asmen-tionedinthe“Proteinuseinlivestockfeeding”chapterinthiscoursemanual).In1988,manycountriesadoptedthethirdrevisionoftheUnitedNationsStandardInternationalTradeClassification (SITC;UN,1998)or theHarmonizedCommodityDescriptionandCoding System of the Customs Cooperation Council (HS; CCC, 2004) causing someconfusion.Inanattempttomaintaincomparabilitywiththesystem(s)upto1987,FAOhasoptedtocontinueusingRevision2oftheSITC,whileattemptingtoadjustthenewclassificationtotheoldone.
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However,problemsandconfusionremain.Forexample,intheclassificationofmeat,certainnationalstatisticsincludeonlygroupingatthethree-digit(SITCRevision2)level,e.g.fresh,chilledorfrozen(code011),ordried,saltedorsmoked(code012).Inthiscaseithasbeennecessarytoredistributethedatafromthethree-digitgroupsamongthefour-digitlevelsubgroups(SITCRevision3),bytakingintoaccounttheinformationfromtradingpartners,whichmayormaynotbeavailableorreliable.Asanotherexample,withintheFAOSTATclassification,meatmeal(code1173)isdefinedas“Flours,mealsand pellets of meat and offal (including of marine mammals); greaves and tankage.Usedforfeed.”(FAOSTAT,2004).Thus,thisclassificationcodedoesnotallowdetermi-nationofdifferentby-producttypesorspeciesoforigin(e.g.mammalian,avian,aquatic)andthereforethepossibilityfortracebackislimited.
Unreportedmovement. Insomeregions, themovementofconsiderablenumbersofanimalsintoneighbouringcountriesremainsunrecorded,eitherintentionallyoruninten-tionally.Toobtainmorerepresentativedataofinternationaltradeinlivecattle,estimatesofunrecordedtradehavebeenmadeandincorporated.Further,blackmarketmovementofcattleandotheragriculturalproducts,aswellasinternationalcrisisaid(cattle,foodandsupplies,whichinmanycasesaredifferentlyclassified),aredifficulttoestimate.
Re-export.Examinationofimportandexportrecordsfromcountriesindicatesthatre-exportofBSEriskproducts,includingcattle,mammalianprotein,andfeedscontainingmammalianproteinhasbeencommon.Therefore,forexample,riskyproductsexportedfromWestEuropetoEastEuropewereoftenre-exportedtotheNearEastorbeyond.Moreover,tradingcompaniesbuyandsellproductsallovertheworldandshipmentsmaychangeownersseveraltimes.Althoughitisknownthatmanyofthesetransactionsoccuronlyonpaperorelectronically,whiletheactualproductremainsinstorage,thenumberoftransactionsmakestheabilitytotrackandtracetheproducts,andthereforedetermine the country of origin, increasingly challenging (Brian Cooke, FEFAC, Per-sonalcommunication,2005).
Post-productioncontamination.Duetothecomplexityofglobaltrade,thereisoftenopportunity forproductswithno inherent risk tobecomecontaminatedwithBSE (orotherdiseaseagents)duringshipmentorstorage.Countriesmustassesstheserisksandconductimportauditstoassurethesafetyofallimportedproducts.
�. ASSESSING BSE EXpOSURE RISk�.1. what we knowItiswellknownthatbeforeBSEwasrecognizedintheworld,globaltradeinlivecattleandbovineproductsincludingMBMandfeedscontainingMBMwaswidespread,espe-ciallyfromindustrializedareassuchastheEUandNorthAmerica(Tables1and2).EvenafterBSEwasrecognizedand itwasdeterminedthattransmissionoccurredthroughlivestock feedcontaining the infectiveagent, trade in theseriskyproductscontinued.For example, export of mammalian protein continued from the EU even after it wasprohibitedfrombeingfedtoruminantsin1994,andcontinueduntilexportwasbannedfromtheUKin1996,Portugalin1998,andtherestoftheEUin2001(EU,2001).
InanattempttoprovidesomegeneralestimateofBSEchallengetocountriesandregionsworldwide,availableimportandexportdatawerecompiledforthehighestriskyears(i.e.1988to2000)forthemostriskyproductsforBSE(livecattleinTable1andinMBMinTable2).ThesedataconfirmthattherewasconsiderabletradeinbothlivecattleandMBMbeforethebansonexportsfromEuropewereimplemented.It isverylikely
��
BSE risk and trade
in animal products
and livestock feeds
thatsomeoftheMBMwasusedinimportingcountriesforthedirectfeedingofrumi-nantlivestock,andimportedMBMwascertainlypresentinfeedmanufacturingplantswiththepotentialforcontaminationofruminantfeedsupplies.ThisimportedMBM,orfeedscontainingthisMBM,maystillbestoredinthesecountries,infeedplantsoronfarms,oritcouldevenstillbecirculatinggloballythroughunregulatedchannels.
�.2. what we don’t knowUptoand includingthepresent time,manycountrieshaveassumedthat there isnoBSEriskwhenimportingfromcountriesthathavenotreportedBSEcases.However(asdescribedinthe“IntroductiontoTSEsandBSE”chapterinthiscoursemanual)thisisclearlynotthecase,astheriskofBSEbeingpresentincountriesoutsideEuropeisstilllargelyunknownbecause:
1. Thelongincubationtimemeansthatsomelevelofinfectivitycanbepresentformanyyearsbeforeclinicalcasesappearinacountry;and
2. Countries vary greatly in their surveillance and reporting of diseases such asBSE.
Therefore, the BSE agent may still be silently amplifying in many, as yet undeter-mined,countriesthatcontinuetoexportriskyproducts.This,inadditiontothelackofaclearabilitytoestablishexactlywhatwastraded,when,andbywhom,meansthatmostcountriesthroughouttheworldhave,knowinglyorunknowingly,receivedsomelevelofexposuretotheBSEagentthroughimports.Further,continueddomesticamplificationandtrademaycontinuetospreadriskyproductsworldwide,despitecontinuedtighten-ingofregulations(HeimandMumford,2005).
Thesespecificconsiderationsarediscussedmorefullyinthe“Introductiontotrans-missiblespongiformencephalopathies”chapterinthiscoursemanual,butthesituationemphasizestheneedforallcountriestoundertakeanationalBSEriskassessmentsothattheglobalBSEsituationcanbevalidlyaddressed.
TABLE 1. Cattle exports from western Europe by importing region
Cattle imports (total number of animals)
Importing region 1��� to 1��0 1��1 to 1��� 1��� to 1���
EasternEurope 48648 192561 157411
NearandMiddleEast 80476 916851 803639
NorthAfrica 209593 1095021 366949
SubSaharanAfrica 5718 3136 969
CentralAmerica 369 418 975
NorthAmerica 31 637 147
SouthAmerica 2030 8780 1149
CentralAsia 0 741 667
EastAsia 450 346 601
SouthAsia 648 1828 188
SoutheastAsia 633 1912
Oceania 216 189 152
Source:FAO(2004).
management of
transmissible
spongiform
encephalopathies
in livestock feeds
and feeding
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TAB
LE 2
. Tra
de m
atri
x fo
r m
eat a
nd b
one
mea
l fro
m 1
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to 1
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by im
port
er (h
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l axi
s) a
nd e
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ter
(ver
tical
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s), i
n m
etri
c to
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orld
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de in
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t and
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e m
eal (
1���
– 1
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Im
port
ing
Coun
try
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rtin
g Co
untr
y N
orth
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ntra
l N
orth
So
uth
East
So
uthe
ast
East
U
nite
d w
est
Nea
r an
d O
cean
ia
Af
rica
Am
eric
a Am
eric
a Am
eric
a As
ia
Asia
Eu
rope
k
ingd
om
Euro
pe
mid
dle
East
Nor
thA
mer
ica
197
15
337
070
276
467
176
79
462
241
341
903
41
779
626
25
036
250
3
Sout
hAm
eric
a
47
66
868
527
21
258
795
140
419
5
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Asi
a
25
00
724
40
192
79
221
152
8
3
Sout
heas
tAsi
a
32
653
Uni
ted
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gdom
3
386
86
103
28,
212
112
69
3,67
8
433
96
115
26
43
Wes
tEur
ope
270
483
182
65
381
212
197
892
936
42
132
067
211
346
21
743
059
126
952
42
Oce
ania
155
853
31
107
440
437
420
337
796
061
81
703
162
822
4
Sour
ce:F
AO(2
004)
.
��
BSE risk and trade
in animal products
and livestock feeds
�. SUmmARy OF TSE-RELEvANT CONCEpTS• ItiscrucialforimportingcountriestoevaluatetheBSEstatusofexportingcoun-
tries, as well as to consider the risks of imported products. Risk assessmentsarealreadyavailableforsomecountriesandinternationalrecommendationsareavailablefromtheOIEdescribingunderwhichconditionsthetradeofcommodi-tiesposeanegligiblerisk.
• Inordertoassessriskandjustifytraderestrictions,itisrequiredthatcountriesperformtheirownnationalBSEriskassessment.
• Giventhedifficultiesinassessingtherisksitmustbeassuredthatallimportedproducts comply with domestic regulations through examination of records oraccreditationofsources,aswellasborderchecks,testingandaudits.
�. REFERENCESCCC (Customs Cooperation Council). 2004. Harmonized commodity description and coding
system.http://www.wcoomd.org/ie/En/AboutUs/aboutus.html
EU (European Union). 2001. EC regulation No. 999/2001 laying down rules for the prevention,
control and eradication of certain transmissible spongiform encephalopathies. http://europa.
eu.int/eur-lex/pri/en/oj/dat/2001/l_147/l_14720010531en00010040.pdf
Eurostat.2004.Externaltradepage.http://epp.eurostat.ec.europa.eu/portal/page?_pageid=1090,3
0070682,1090_33076576&_dad=portal&_schema=PORTAL
FAOSTAT. 2004. FAO statistical databases, FAO, Rome. http://apps.fao.org/. Data specifically for
agriculture:http://faostat.fao.org/faostat/collections?subset=agriculture
Heim D, mumford E.2005.ThefutureofBSEfromtheglobalperspective.MeatScience70:555-
562
OIE (world Organization for Animal Health).2005a.Bovinespongiformencephalopathy.TerrestrialAnimalHealthCode,Chapter2.3.13.http://www.oie.int/eng/normes/MCode/en_chapitre_2.3.13.
htm
UN.1998.Statisticalpapers,seriesM,No.34.Revision3,StatisticalOfficeoftheUnitedNations.
http://unstats.un.org/unsd/publication/SeriesM/SeriesM_34rev3E.pdf
UN. 2004.UNpublications,statisticsandstatisticalmethodspublications: trade.http://unstats.
un.org/unsd/pubs/gesgrid.asp?class=trade
world Bank.2005.Foodsafetyandagriculturalhealthstandards:challengesandopportunitiesfor
developingcountryexports.WorldBankReport31207,January10,2005.
wTO (world Trade Organization).1994.Agreementonsanitaryandphytosanitarymeasures.FinalActoftheUruguayRound,Article5.http://www.wto.org/english/docs_e/legal_e/15-sps.pdf
1AppENDIX
Authors and course contributors
�3
Appendix 1
Authors and course contributors
AUTHORS AND COURSE CONTRIBUTORS
Brian Cooke EuropeanFeedManufacturer’sFederation,Brussels,BelgiumGeneviève Frick Agroscope,Liebefeld-Posieux,SwitzerlandChristine Friedli SAFOSO,Berne,SwitzerlandOlivier Fumière WalloonAgriculturalResearchCentre,Gembloux,BelgiumDaniel Guidon Agroscope,Liebefeld-Posieux,SwitzerlandFritz Hartmann Hokovit,Bützberg,SwitzerlandHans Hofer Centravo,Lyss,SwitzerlandDagmar Heim SwissFederalVeterinaryOffice,Berne,SwitzerlandUlrich kihm SAFOSO,Berne,SwitzerlandJörg Löpfe SwissTechnicalServicesAG,Wallisellen,SwitzerlandElizabeth mumford SAFOSO,Berne,SwitzerlandErnst Nef SwissInstituteofFeedTechnology,Uzwil,SwitzerlandLukas perler SwissFederalVeterinaryOffice,Berne,SwitzerlandAlexandra Roetschi Agroscope,Liebefeld-Posieux,SwitzerlandHeinz Soltermann Centravo,Lyss,SwitzerlandAndrew Speedy FAO,AnimalProductionandHealthDivision,Rome,Italy
Participants from the partner countries have also contributed significantly to theproductionand translationof thecoursemanuals,and tomanyotheraspectsof thecourses.
2AppENDIX
Related background reading and web links*
*ThesereferencesandWeblinksrefertoallfourCapacityBuildingforSurveillanceand Prevention of BSE and Other Zoonotic Diseases project course manuals.Therefore,alldocumentsandlinksmaynotbeapplicabletothetopicscoveredinthismanual.
*ThesereferencesandWeblinksrefertoallfourCapacityBuildingforSurveillanceand Prevention of BSE and Other Zoonotic Diseases project course manuals.Therefore,alldocumentsandlinksmaynotbeapplicabletothetopicscoveredinthismanual.
��
Appendix 2
Related background reading and web links
RELATED BACkGROUND READING AND wEB LINkS
TSE pages of selected ministries and other general data sourcesDepartment of Environment Food and Rural Affairs. United Kingdom, BSE homepage:
http://www.defra.gov.uk/animalh/bse/index.html
FAO. BSEpages:http://www.fao.org/ag/AGAinfo/subjects/en/health/bse/default.html
ministry of Agriculture of New Zealand. BSE homepage: http://www.biosecurity.govt.nz/
node/7650
Swiss Federal veterinary Office. BSE homepage: http://www.bvet.admin.ch/gesundheit_tiere/
01752/01804/02075/index.html?lang=de
TAFS.Positionpapers:http://www.tseandfoodsafety.org/startseite.htm
United States Department of Agriculture. Animal and Plant Health Inspection Service, BSE
homepage:http://www.aphis.usda.gov/lpa/issues/bse/bse.html
wHO.BSEpages:http://www.who.int/zoonoses/diseases/bse/en/
International standardsOIE. Bovine spongiform encephalopathy. Terrestrial Animal Health Code, Chapter 2.3.13. http://
www.oie.int/eng/normes/MCode/en_chapitre_2.3.13.htm
OIE. Factors to consider in conducting the bovine spongiform encephalopathy risk assessment
recommendedinchapter2.3.13.TerrestrialAnimalHealthCode,Appendix3.8.5.http://www.oie.
int/eng/normes/MCode/en_chapitre_3.8.5.htm
OIE.Surveillanceforbovinespongiformencephalopathy.TerrestrialAnimalHealthCode,Appendix
3.8.4.http://www.oie.int/eng/normes/MCode/en_chapitre_3.8.4.htm
OIE. Procedures for the reduction of infectivity of transmissible spongiform encephalopathy
agents.TerrestrialAnimalHealthCode,Appendix3.6.3.http://www.oie.int/eng/normes/MCode/
en_chapitre_3.6.3.htm
OIE.1994.AgreementonSanitaryandPhytosanitaryMeasures.FinalActoftheUruguayRound,Article5.http://www.wto.org/english/docs_e/legal_e/15-sps.pdf
BSE cases and risk EC. BSE testing results of member countries of the EU. http://europa.eu.int/comm/food/food/
biosafety/bse/mthly_reps_en.htm
OIE.NumberofreportedcasesofBSEworldwide.http://www.oie.int/eng/info/en_esbmonde.htm
OIE.ResolutionNo.XXVII,Recognitionofthebovinespongiformencephalopathystatusofmember
countrieshttp://www.oie.int/eng/info/en_statesb.htm#List
SSC. 2002. Opinion on TSE infectivity distribution in ruminant tissues (state of knowledge,
December2001).AdoptedbytheScientificSteeringCommitteeatitsmeetingof10-11January
2002.http://europa.eu.int/comm/food/fs/sc/ssc/out241_en.pdf
SSC.OpinionsoftheScientificSteeringCommitteeoftheEC.http://europa.eu.int/comm/food/fs/
sc/ssc/outcome_en.html
management of
transmissible
spongiform
encephalopathies
in livestock feeds
and feeding
��
measuresEU. 2002. Regulation No 1774/2002. Laying down health rules concerning animal by-products
not intended for human consumption. http://europa.eu.int/eur-lex/pri/en/oj/dat/2002/l_273/
l_27320021010en00010095.pdf
European Union Guidance Document for Regulation 1��4/2002. http://europa.eu.int/comm/food/
fs/bse/bse48_en.pdf
FAO. 2004. Good practices for the meat industry. FAO Animal Production and Health Manual
No. 2. Rome (also available at: ftp://ftp.fao.org/docrep/fao/007/y5454e/y5454e00.pdf).
FAO. 2004. protein sources for the animal feed industry. Proceedings of the FAO Expert
ConsultationandWorkshop,Bangkok,29April-3May2002.FAOAnimalProductionandHealth
ProceedingsNo.1.Rome(alsoavailableathttp://www.fao.org/documents/show_cdr.asp?url_)
file=/docrep/007/y5019e/y5019e00.htm
FAO. 2007. Management of transmissible spongiform encephalopathies in livestock feeds andfeeding.Coursemanual,ProjectCapacityBuildingforSurveillanceandPreventionofBSEandOtherZoonoticDiseases.Rome
FAO. 2007. Management of transmissible spongiform encephalopathies in meat production.Course manual, Project Capacity Building for Surveillance and Prevention of BSE and OtherZoonoticDiseases.Rome
Heim D, kihm U. 2003. Risk management of transmissible spongiform encephalopathies in
Europe.RevScitechOffintEpiz22(1),179-199
Heim D, mumford E.2005.ThefutureofBSEfromtheglobalperspective.MeatScience70:555-
562
Heim D, murray N.2004.Possibilities tomanage theBSEepidemic:cohortcullingversusherd
culling–experiencesinSwitzerland.In:Prions:achallengeforscience,medicineandthepublichealthsystem,2nded.EdsHFRabaneau,JCinatl,HWDoerr.Karger,Basel,Switzerland.pp
186-192
OIE.2005.DiseasesnotifiabletotheOIE.http://www.oie.int/eng/maladies/en_classification.htm
Render – The National magazine of Rendering. 2004. Rendering 101: Raw material, renderingprocess,andanimalby-products.http://www.rendermagazine.com/August2004/Rendering101.pdf
The BSE Inquiry. 2000.Thereport.TheinquiryintoBSEandvariantCJDintheUnitedKingdom,Volume13: Industryprocessesandcontrols,Chapter6,Rendering.http://www.bseinquiry.gov.
uk/report/volume13/chapter6.htm
DiagnosticsEFSA. 2006.EFSAScientific reportson theevaluationofBSE/TSE tests.http://www.efsa.eu.int/
science/tse_assessments/bse_tse/catindex_de.html
OIE. 2005. Bovine spongiform encephalopathy. Manual of diagnostic tests and vaccines forterrestrialanimals,Chapter2.3.13.http://www.oie.int/eng/normes/mmanual/A_00064.htm
Safar JG, Scott m, monaghan J, Deering C, Didorenko S, vergara J, Ball H, Legname G, Leclerc
E, Solforosi L, Serban H, Groth D, Burton DR, prusiner SB, williamson RA. 2002.Measuring
prionscausingbovinespongiformencephalopathyorchronicwastingdiseasebyimmunoassays
andtransgenicmice.NatBiotechnol20(11):1147-1150.
��
Appendix 2
Related background reading and web links
SurveillanceCameron AR, Baldock FC. 1998. Two-stage sampling in surveys to substantiate freedom from
disease.PrevVetMed34:19-30
Salman mD.2003.AnimalDiseaseSurveillanceandSurveySystems.MethodsandApplications.
IowaStatePress,Ames,Iowa,USA
Scheaffer RL, mendenhall w, Ott L.1990.ElementarySurveySampling.DuxburyPress,Belmont
CA.
Clinical examinationBraun U, kihm U, pusterla N, Schönmann m.1997.Clinicalexaminationofcattlewithsuspected
bovinespongiformencephalopathy(BSE).SchweizArchTierheilk139:35-41(alsoavailableat:
http://www.bse.unizh.ch/english/examination/htmlsklinischer.htm)
Human prion diseasesDepartment of Health,UnitedKingdom.CJD-homepage:
http://www.dh.gov.uk/PolicyAndGuidance/HealthAndSocialCareTopics/CJD/fs/en
3AppENDIX
Glossary of technical terms and acronyms*
*ThisglossaryreferstoallfourCapacityBuildingforSurveillanceandPreventionofBSEandOtherZoonoticDiseasesprojectcoursemanuals.Therefore,alldocu-mentsandlinksmaynotbeapplicabletothetopicscoveredinthismanual.
3AppENDIX
Glossary of technical terms and acronyms*
*ThisglossaryreferstoallfourCapacityBuildingforSurveillanceandPreventionofBSEandOtherZoonoticDiseasesprojectcoursemanuals.Therefore,alldocu-mentsandlinksmaynotbeapplicabletothetopicscoveredinthismanual.
103
Appendix 3
Glossary of technical terms and acronyms
GLOSSARy OF TECHNICAL TERmS AND ACRONymS
AAFCO AssociationofAmericanFeedControlOfficials
Ab Antibody
AFIA AmericanFeedIndustryAssociation
Animal by-products Tissues and other materials (including fallen stock) dis-cardedattheslaughterhouse,whichgenerallygotoincin-eration,burialorrendering(dependingonthecountry)
Animal waste Animalby-products
Ante mortem Before death (generally refers to the period immediatelybeforeslaughter)
Ap Apparentprevalence
BAB Bornaftertheban;animalswithBSEthatwerebornafterimplementationofafeedban
BARB Bornafter the realban;animalswithBSE thatwerebornafter implementation of a comprehensive and effectively-enforcedfeedban
BSC Biosafetycabinet
BSE Bovinespongiformencephalopathy
BL Biosafetylevel
By-pass proteins Proteinsthatarenotdegradedintherumenbutaredigest-edinthesmallintestinetoprovideadditionalaminoacids
CCp Critical Control Point: a step in a production chain that isessential to prevent or eliminate a food safety hazard orreduceittoanacceptablelevelandatwhichacontrolcanbeapplied
CEN EuropanCommitteeforStandardization
CJD Creutzfeldt-JakobDisease
CNS Centralnervoussystem
Combinable crops Thoseabletobeharvestedwithacombine
Contaminants Materialsthatshouldnotbepresentinagivenproduct;e.g.rodents,birds,rodentdroppings,toxinsandmouldarecon-taminantsthatshouldnotbepresentinanylivestockfeed
Control (noun) The state wherein correct procedures are being followedandcriteriaarebeingmet(HACCPcontext)
Control (verb) Totakeallnecessaryactionstoensureandmaintaincom-pliancewithcriteriaestablishedinaHACCP(orothercon-trol)plan(HACCPcontext)
Core fragment ThepartofPrPScthatisnotdigestedbyproteinaseK(alsocalledPrPRes)
management of
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104
Critical limit Acriterionthatseparatesacceptabilityfromunacceptability(e.g.duringaudits)
Cross contaminants Substancescarriedfromareasormaterialswheretheyarenotprohibitedtoareasormaterialswheretheyareprohib-ited
Cross feeding The feeding of a livestock group with prohibited feedsintendedforanotherlivestockgroup
Cp Crudeprotein
CwD Chronicwastingdisease.
DNA Deoxyribonucleic acid; the genetic material for all livingorganismsexceptbacteria
Downer cattle Cattletoosicktowalktoslaughter(definitiondiffersamongcountries)
EC EuropeanCommission
EFSA EuropeanFoodSafetyAuthority
ELISA Enzyme-linkedimmunosorbentassay
Emergency slaughter Slaughter cattle with clinical signs non-specific for BSE(definitiondiffersamongcountries)
Epitope Structuralpartofanantigenthatreactswithantibodies
Epitope demasking Processinwhichtheepitopebecomesavailableforantibodybinding(forexample,bydenaturation)
Essential amino acids Those that cannot be synthesized and therefore must beprovidedbythefeed/food
EU EuropeanUnion
Fallen stock Cattlethatdiedorwerekilledforunknownreasons(defini-tiondiffersamongcountries)
FAO FoodandAgricultureOrganizationoftheUnitedNations
FDA FoodandDrugAdministration(UnitedStatesofAmerica)
FEFAC EuropeanFeedManufacturers’Federation
FIFO Firstinfirstout;aproductionconcepttooptimizequality
Flushing batches Batchesof feedprocessedortransported in-betweenfeedbatchescontainingprohibitedandnon-prohibitedmaterials,andintendedtoremovetracesofprohibitedmaterialsfromtheequipment
FmD Foot-and-mouthdisease
FN False negatives; truly-diseased animals that test negativeonadiagnostictest
Fp Falsepositives;trulynondiseasedanimalsthattestpositiveonadiagnostictest
FSE Felinespongiformencephalopathy;TSEincats,believedtobecausedbyingestionoftheBSEagent.
GAFTA GrainandFeedTradeAssociation
10�
Appendix 3
Glossary of technical terms and acronyms
GAp Goodagriculturalpractices
GBR GeographicalBSEriskassessment
GHp Goodhygienepractices
Gmp GoodManufacturingPractices
GmT Goodmicrobiologicaltechnique
Greaves Aproteinaceousby-productoftherenderingprocess
GTm GAFTATradersManual
H & E Haematoxylinandeosinstain
HACCp Hazard Analysis and Critical Control Points: a method toidentifyprocessstepswherea lossorsignificantdeviancefromtherequiredproductqualityandsafetycouldoccurifnotargetedcontrolisapplied
HACCp plan Adocumentprepared inaccordancewith theprinciplesofHACCPtoensurecontrolofhazardsthataresignificantforthesegmentoftheproductionunderconsideration
Hazard Abiological,chemicalorphysicalagentwiththepotentialtocauseanadversehealtheffect
Hazard analysis The process of collecting and evaluating information onhazardsandconditionsleadingtotheirpresencetodecidewhich are significant for the segment of the produc-tion under consideration and therefore which should beaddressedinthecontrol(orHACCP)plan
High quality protein Proteinsourcesthatmatchtherequirementsofaparticularspeciesorproductionclasswell
HpLC Highperformanceliquidchromatography
IAG EuropeanFeedMicroscopistsworkinggroup
IFIF InternationalFeedIndustryFederation
IHC Immunohistochemistry
Indigenous BSE case DomesticBSEcase;non-importedBSEcase
m+C Methioninepluscysteine;aminoacidsgenerallyconsideredtogether,becausecysteinecanbederivedfrommethionineinanimals
ISO InternationalOrganizationforStandardization
mammal Ananimalthatlactates;inthiscontext,livestockexcludingaquaticspeciesandpoultry
mBm Meatandbonemeal; thesolidproteinproductof theren-deringprocess
medulla oblongata Caudalportionofthebrainstem
mmBm Mammalianmeatandbonemeal
monitoring Anongoingprocessofspecificanimalhealthdatacollectionoveradefinedperiodoftime
monogastric species Animalswithsimplestomachs(e.g.swine,poultry,horses,humans)
management of
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mOSS Monitoringandsurveillancesystem
mRm Mechanicallyrecoveredmeat
NIRC Nearinfraredcamera
NIRm Nearinfraredmicroscopy
NIRS Nearinfraredspectrography
Notifiable disease Adiseaseforwhichthereisanationallegalrequirementtoreportcasesandsuspectstoanofficialauthority
Obex Thepointonthemidlineofthedorsalsurfaceofthemedullaoblongata thatmarks thecaudalangleof the fourthbrainventricle;amarkerfortheregionofthebrainstemwheresomeof thepredilection areas forhistological lesionsandPrPSc deposition in BSE are located (such as the dorsalnucleusofthevagus)
OD Opticaldensity
OIE WorldOrganisationforAnimalHealth
Om OpticalMicroscopy
OR Oddsratio
pathogenicity Ability of an organism to invade a host organism and tocausedisease
pCR Polymerasechainreaction
pithing The laceration of central nervous tissue by means of anelongated rod-shaped instrument introduced into the cra-nialcavityofslaughtercattleafterstunning.
pk Proteinase K; a serine proteinase that digests PrPC com-pletelybutPrPSconlypartiallyundercertainconditions
post mortem Afterdeath
prion InfectiousagentcausingTSE
proteolysis Cleavage of a protein by proteases; also referred to as“digestion”
prp Prion protein, encoded by the gene PRNP, expressed bymanycelltypesandmanyorganisms
prpBSE Resistant prion protein associated with bovine spongiformencephalopathy;alsocalledPrPSc
prpC Normalprionproteinfoundineukaryoticcells
prpRes Resistantprionproteincore remainingafterproteolysisofPrPScusingproteinaseK
prpSc Resistant prion protein associated with transmissiblespongiformencephalopathies,includingBSE
prpSens Normalprionproteinfoundineukaryoticcells;alsocalledPrPC
pv Predictivevalue
10�
Appendix 3
Glossary of technical terms and acronyms
Rapid test Test systems using immunological assays that detect thepresence of infectious agents in animal tissues or othermaterialswithinhours
RR Relativerisk
Ruminant species Animals with multichambered stomachs that allow bacte-rial fermentationof feedsprior to intestinaldigestion (e.g.cattle,sheep,goats,camellids)
Scrapie ATSEofsheepandgoats
SE Sensitivityofadiagnostictest
Segregation Undesirable separation of raw ingredients in a compoundfeedafterprocessing
SFT SwissInstituteofFeedTechnology
Sick slaughter Cattle with non-specific signs (definition differs amongcountries)
Sp Specificityofadiagnostictest
SpS Agreement AgreementontheApplicationofSanitaryandPhytosanitaryMeasures
SRm Specifiedriskmaterials;thoseanimaltissuesmostlikelytocontainTSEinfectivematerial
SSC Scientific Steering Committee of the European Commis-sion
Strip test Lateralflowimmunochromatographictestforrapiddetec-tionofproteinsinfeedsamples
Surveillance Extension of monitoring in which control or eradicationactionistakenonceapredefinedlevelofthehealth-relatedeventhasbeenreached
TAFS InternationalForumforTSEandFoodSafety
TBT Agreement AgreementonTechnicalBarrierstoTrade
Terrestrial animal In thiscontextall livestockexcludingaquaticspecies (e.g.poultry,ruminants,pigs,horses)
TmE Transmissibleminkencephalopathy
Tp Trueprevalence
Tracing Determiningwhereananimalorproductoriginatedorhasbeen
Tracking Following an animal or product forward through the sys-tem
TSE Transmissiblespongiformencephalopathy
Uk UnitedKingdomofGreatBritainandNorthernIreland
USA UnitedStatesofAmerica
vCJD Variant (or new variant) Creutzfeldt-Jakob disease ofhumans; believed to be caused by ingestion of the BSEagent
management of
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spongiform
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in livestock feeds
and feeding
10�
wB Westernblot
wHO WorldHealthOrganization
wTO WorldTradeOrganization
Additionaldefinitionscanbefoundin• the OIE Terrestrial Animal Code, Chapter 1.1.1. http://www.oie.int/eng/normes/
MCode/en_chapitre_1.1.1.htm• theFAO/WHOCodexAlimentarius“Currentofficialstandards”.http://www.codex-
alimentarius.net/web/standard_list.do?lang=en
4AppENDIX
project summary
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Appendix 4
project summary
pROJECT SUmmARy
ThiscourseisapartoftheprojectCapacityBuildingforSurveillanceandPreventionofBSEandOtherZoonoticDiseases.Theaimoftheprojectistobuildcapacity,establishpreventivemeasuresandanalyserisksforbovinespongiformencephalopathy(BSE),sothat,ultimately,partnercountriesareableeithertoprovethemselvestobeBSE-freeorareabletodecreasetheirBSErisktoanacceptablelevel.Governmentalandprivateveterinary services, diagnostic laboratories, and the livestock, food and animal feedindustrieswillbestrengthenedandsupported,andtechnicalcapacitybuiltateverystepalongthefoodproductionchain.Inthefuture,theknowledgegainedduringthisprojectcould be used by the countries to establish similar programmes for control of otherzoonoticfood-bornepathogens.
TheprojectisfundedbySwissgovernmentalagenciesandutilizesexpertiseavailableinSwitzerlandandworldwideandinfrastructureavailablefromtheFoodandAgricul-tureOrganizationoftheUnitedNations(FAO)toassistthegovernmentsofthepartnercountriestoachievetheproject’saim.TheexecutingagencyisSafeFoodSolutionsInc.(SAFOSO)ofBerne,Switzerland.
The direct project partner in each country is the National Veterinary Office. Thecountriescommitandpayasalary toat leastone individual,situated in theNationalVeterinaryOffice,toactasaNationalProjectCoordinator(NPC),committhreetraineespercourseandprovidethenecessaryinfrastructureforimplementationoftheprojectinthecountry.TheNPCisresponsibleforcoordinatingtheactivitiesoftheprojectwithinthecountry,includingofferingtrainingcourses,identifyingandorganizingtrainees,andpromotingcommunicationbetweentheproject,thegovernment,thescientificcommu-nityinthecountry,thelivestockandfoodindustries,andthepublic.Othercommitmentsby the countries include providing paid leave time for employees to attend courses,providing infrastructure and facilities for in-country courses, providing historical andcurrentdata(surveillancedata,animalmovementdata,import/exportrecords)andthestaffrequiredtoidentifythosedata,andprovidingadequatestaffforandfacilitatingtheinitialneedsassessmentandfinalcomprehensiveriskassessment.
ANationalProjectBoardineachoftheparticipatingcountriesregularlyevaluatestheoperationalprogressandneedsoftheproject,andprovidesaregularvenueforcom-munication among the project team, national partners and stakeholders. This BoardiscomprisedoftheNPC,representativesofthenationalgovernment,aprojectrepre-sentative,thelocalFAOrepresentative,andlocalstakeholdersfromprivateindustryandtheveterinarycommunity.
ACTIvITIES OF THE pROJECT1. Thespecificneedsofeachparticipatingcountryareassessed.2. Comprehensive courses to “train the trainers” are provided in Switzerland (or
elsewhere)toselectedparticipantstoimproveunderstandingoftheepidemiologyofandrelevantriskfactorsforBSEandtodevelopspecificknowledgeandskillsforimplementingappropriatecontrols.
management of
transmissible
spongiform
encephalopathies
in livestock feeds
and feeding
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Threetraineesfromeachcountry,aswellastheNPC,traveltoSwitzerland(orelse-where)toparticipateineachcourse.
Thecoursesare:• DiagnosticTechniquesfortransmissiblespongiformencephalopathies• Epidemiology, Surveillance and Risk Assessment for transmissible spongiform
encephalopathies• Transmissiblespongiformencephalopathiesmanagementinlivestockfeedsand
Feeding• TransmissiblespongiformencephalopathiesManagementinMeatProduction
EachcourseisprecededbyanintroductiontoBSEcoveringthebackgroundoftrans-missiblespongiformencephalopathies,BSE,biosafety,generalconceptsofepidemiolo-gyandriskassessment,andriskcommunication.Eachcoursealsoincludesdiscussionofaspectsofriskcommunicationthatarerelevanttothetopicbeingpresented.
Onlythosemotivatedindividualswhowillbeimplementingtherelevantinformationinto the national BSE programme, who have some experience (e.g. ability to use amicroscope,veterinarytraining)andhaveadequateEnglishskills,areaccepted.
After each course, the relative success of the course is evaluated focusing on thesuccess of the training methods and effectiveness of the knowledge transfer ratherthanonthelearningoftheindividualtrainees.Therefore,nowrittentestisgiven,butclosecontact ismaintainedwiththetraineesaftertheyreturntotheircountries,andtheirprogressandsuccess in implementationof their training into thenationalBSEprogrammeisfollowedandevaluatedinthefield.
3. Eachof theTSE-specificcourses is thenofferedasan in-countrycourse in thenative language, and is organized by the trainees and the National VeterinaryOfficeswithtechnicalsupportfromtheproject.In-countrycoursesusethesamecurriculumandexpectedoutcomesastheoriginalcourses,andareprovidedwithsupport,technicalassistanceandmaterials(translatedintotheirownlanguage).TheintroductoryTSEandbiosafetycoursecurriculumisalsopresented.Atleastoneexpert trainerassists inpresenting thesecourses.Participantsarechosenaccordingtostrictselectioncriteria,butthenumberofparticipantsandthefre-quencyandlocationofcoursesgivendependsontheneedsofthecountryandthetypeofcourse.
4. The knowledge gained through the courses should then be integrated by thepartnercountrythroughdevelopmentandimplementationofanationalBSEcon-trolprogramme.Theprogrammeispromotedandsupportedbythecountriestoensurethesustainabilityofthesystem.Contact,technicalsupportandfollow-upwiththecountriesisongoingthroughouttheproject.
5. InformationcampaignstoimproveBSEawarenessaretargetedtonationalgov-ernments,producersandconsumers.
6. PartnercountriesaresupportedinthesubmissionofacomprehensivenationalBSEriskassessmenttotheWorldOrganisationforAnimalHealth(OIE)inordertodocumenttheirBSEstatustotheinternationalcommunity.