stec contamination in raw milk cheese : risk assessment · raw milk cheese risk assessment v3.0...

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Raw milk cheese risk assessment v3.0 08/11/16 1 STEC contamination in raw milk cheese : risk assessment This document should be read in conjunction with version 2.0 of the risk assessment. This version incorporates new information received by FSS since 14 September 2016 and does not reiterate all the factual information incorporated in version 2.0 - this remains the same. 1) STATEMENT OF PURPOSE AND APPROACH 1.1 Purpose This document assesses the potential risks to public health associated with shiga toxin producing Escherichia coli (STEC) 1 contamination of the raw milk cheeses produced by Errington Cheese Limited (ECL), South Lanarkshire. 1.2 Definition of raw milk cheese As version 2.0 1.3 Approach As version 2.0 This risk assessment is version 3.0 and is current as of 08 November 2016 to reflect new information which has become available since version 2.0 (14 September 2016). It contains additional information on sampling results from cheese, new sampling results from milk and updated epidemiological information. 2) HAZARD IDENTIFICATION As version 2.0 3) EXPOSURE ASSESSMENT 3.1 Supply of raw milk to ECL As version 2.0 3.2 ECL’s raw milk specification As version 2.0 3.3 Current scientific literature on occurrence of STEC in raw milk As version 2.0 The Center for Science in the Public Interest (CSPI) has published a report on Foodborne Disease Outbreaks and analysis from 1998-2007 2 . This report includes data on dairy products and there are numerous examples of outbreaks and recalls 1 STEC is synonymous with VTEC (vero-cytotoxin producing E. coli), as are vtx and stx genes. 2 http://www.milkfacts.info/Milk%20Microbiology/Disease%20Outbreaks.htm

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Raw milk cheese risk assessment v3.0 08/11/16

1

STEC contamination in raw milk cheese : risk assessment This document should be read in conjunction with version 2.0 of the risk assessment. This version incorporates new information received by FSS since

14 September 2016 and does not reiterate all the factual information incorporated in version 2.0 - this remains the same.

1) STATEMENT OF PURPOSE AND APPROACH 1.1 Purpose This document assesses the potential risks to public health associated with shiga

toxin producing Escherichia coli (STEC)1 contamination of the raw milk cheeses

produced by Errington Cheese Limited (ECL), South Lanarkshire.

1.2 Definition of raw milk cheese

As version 2.0 1.3 Approach As version 2.0

This risk assessment is version 3.0 and is current as of 08 November 2016 to reflect

new information which has become available since version 2.0 (14 September

2016). It contains additional information on sampling results from cheese, new

sampling results from milk and updated epidemiological information.

2) HAZARD IDENTIFICATION

As version 2.0

3) EXPOSURE ASSESSMENT

3.1 Supply of raw milk to ECL As version 2.0

3.2 ECL’s raw milk specification As version 2.0

3.3 Current scientific literature on occurrence of STEC in raw milk As version 2.0

The Center for Science in the Public Interest (CSPI) has published a report on

Foodborne Disease Outbreaks and analysis from 1998-20072. This report includes

data on dairy products and there are numerous examples of outbreaks and recalls

1 STEC is synonymous with VTEC (vero-cytotoxin producing E. coli), as are vtx and stx genes.

2 http://www.milkfacts.info/Milk%20Microbiology/Disease%20Outbreaks.htm

Raw milk cheese risk assessment v3.0 08/11/16

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associated with raw milk (and raw milk cheeses) for a range of pathogens including

STEC.

3.4 ECL Cheese Product Descriptions

The following table summarises the cheeses made by ECL, which type of milk is

used to manufacture them and the type of cheese produced.

Cheese Milk Description

Dunsyre Blue Unpasteurised Cow

Blue cheese

Lanark White Unpasteurised Ewe

Semi-hard white cheese

Lanark Blue Unpasteurised Ewe

Blue cheese

Maisie’s Kebbuck

Unpasteurised Cow

Semi-hard white cheese

Corra Linn Unpasteurised Ewe

Hard white cheese

Sir Lancelot Unpasteurised

Ewe

Lactic cheese

Further information on the cheeses produced by ECL can be found on their website3.

3.5 Specification of cheese including critical controls.

The generic HACCP plan (annex 1 version 2.0) covers all 6 cheeses (Dunsyre Blue,

Lanark Blue, Lanark White, Maisie’s Kebbuck, Corra Linn and Sir Lancelot) made by

ECL. It covers all aspects of the cheese making process from collection of ewes’ milk

from the bulk tank at milk suppliers [name] and acceptance of cows’ milk from the

dedicated farm [names] delivered through [name].

3.6 Current literature on occurrence of STEC in cheese

Analysis of food incident date by the Horizon Scan system4, has shown that between

1st November 2014 and 1st November 2016, there have been at least 70 food safety

notifications worldwide relating to the presence of E. coli (including STEC) in cheese

products. At least 23 of these warnings related to unpasteurised products (not all

cheeses were defined as pasteurised or unpasteurised) and 58 related to cheese

produced within the EU (including 39 from France), 10 outside the EU and 2 were of

unknown origin. Fifty one safety warnings were issued by EU countries including 23

through the EC Rapid Alert System for Food and Feed. The data shows that other

member states are testing for a wide range of different STEC serotypes and that

some alerts are based on the detection of stx genes.

3 http://www.erringtoncheese.co.uk/cheese.php

4 https://horizon-scan.fera.co.uk/

Raw milk cheese risk assessment v3.0 08/11/16

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3.7 Epidemiology

Since 14 September, 4 further cases have been confirmed as part of the outbreak

bringing the total number of confirmed cases to 26. HPS are undertaking further

statistical analysis on the epidemiological evidence and this information will be

reported in the final IMT report.

3.8 Cheese production

Dunsyre Blue production as version 2.0.

All types of cheese produced by ECL are batch coded as outlined for Dunsyre Blue

e.g. the letter denotes the month of production and the number corresponds to the

day of production.

Growth and survival of pathogenic E. coli is dependent on the simultaneous effect of

a number of environmental factors such as pH, aw and temperature. However, the

parameters outlined in version 2.0 remain the same regardless of cheese type.

FSS were provided pH and aw results from two batches of Dunsyre Blue sampled by

South Lanarkshire Council (SLC). However, FSS has not received any information

on the physico-chemical characteristics, predictive modelling of pathogen growth or

challenge testing for any of the other cheese types manufactured by ECL.

3.9 Microbiological Quality of Raw Milk and Cheese

ECL Sampling

As version 2.0

Local Authority Sampling

The following information is a summary of all of the testing results done to date,

detailing what information was known before and since version 2.0 of the risk

assessment (14 September 2016). A summary of all positive results to date are

attached in Annex 9.

Dunsyre Blue

As of the 14 September:

Batch F15: A stx2 positive non-O157 E. coli (STEC) had been isolated and

cultured in a sample from F15. Nine further samples from batch F15 had been

found to contain the stx2 gene, and were undergoing further confirmatory

analysis. Whole genome sequencing (WGS) of the F15 STEC demonstrated

the presence of an E. coli, O-unidentifiable:H20, stx2d, ST1308.

Raw milk cheese risk assessment v3.0 08/11/16

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Batch E24: Two samples taken from Batch E24 had been found to contain the

stx2 gene (i.e. presumptive positive for STEC).

Batch G12: One sample taken from Batch G12 had been found to contain the

stx2 gene (i.e. presumptive positive for STEC).

Other Dunsyre Blue samples: 22 other samples from additional batches

(n=21) were negative for both stx genes and E. coli O157.

Since 14 September:

Batch F15: WGS results of a second F15 isolate confirmed the same profile

as 1st F15 sample (i.e. the presence of an E. coli, O-unidentifiable:H20, stx2d,

ST1308).

Batch E24: no further results (i.e. the two samples remain presumptive

positive for STEC on the basis of the detection of stx2 genes).

Batch G12: no further results (i.e. the sample remains presumptive positive for

STEC on the basis of detection of the stx2 gene).

The results of 16 further batches of Dunsyre Blue have not been found to

contain E. coli or stx genes.

Lanark White

As of the 14 September:

Batch G14: A stx gene negative E. coli O157 had been isolated from a sample

from Batch G14.

Batch H24: A sample taken from Batch H24 had been found to contain the

stx2 gene (i.e. it was considered presumptive positive for STEC).

Since 14 September:

Batch G14: The original sample from Batch G14 was found by WGS to

contain E. coli O157:H42 ST P3216 stx negative. A further sample from

Batch G14 was found to contain a stx negative E. coli O157 and WGS results

confirmed that this organism was the same as that found in the other sample

(i.e. E. coli O157:H42 ST P3216 stx negative).

Batch H3: A stx gene negative E. coli O157 was found in this sample, WGS

confirmed it to be the same strain of organism as was contained in the sample

from Batch G14 (i.e. E. coli O157:H42 ST P3216 stx negative).

Raw milk cheese risk assessment v3.0 08/11/16

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Batch H24: this sample was also found to contain a stx gene negative E. coli

O157. WGS confirmed it to be the same strain of organism as was contained

in the sample from Batch G14 and H3 (i.e. E. coli O157:H42 ST P3216 stx

negative). The stx2 gene detected in the sample originally may belong to

another STEC present in the sample, or may be part of free DNA or a dead

organism, and is therefore uncultivable.

Lanark Blue

No positive Lanark Blue results were notified to FSS up to and including the 14th

September.

Since 14 September:

Batch E24: this sample has been found to contain a non-O157 E. coli with the

stx2 gene – i.e. an STEC. It is currently being whole genome sequenced at

PHE.

Other Cheeses produced by ECL

Limited sampling has been undertaken of the other cheeses produced by ECL.

Samples were taken from 1 batch of Maisie’s Kebbuck; 3 batches of Corra Linn and

1 batch of Sir Lancelot. No E. coli or stx genes were detected in these 5 samples.

Milk Samples

As of the 14 September, the only results notified to FSS relating to milk samples

were those taken by ECL as per their sampling plan. These results are detailed in

version 2.0 annex 3.

Since 14 September:

A sample of raw cows’ milk taken from the bulk tank on the 29 September

has been found to contain a stx2 positive non-O157 E. coli i.e. an STEC. It is

currently being sequenced at PHE.

A further sample of raw cows’ milk taken on the 19 October has been found to

contain a stx1 and stx2 positive non-O157 E. coli i.e. an STEC. It is currently

being sequenced at PHE.

3.10 Other potential sources of STEC contamination

As version 2.0

4) HAZARD CHARACTERISATION

Raw milk cheese risk assessment v3.0 08/11/16

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4.1 Disease symptoms

As version 2.0

4.2 Dose response

As version 2.0

4.3 Susceptible population

As version 2.0

4.4 Particular subtypes found in humans and cattle in Scotland

As version 2.0

5) RISK CHARACTERISATION

5.1 Likelihood of STEC being present in the raw milk

As version 2.0 although this specifically focusses on Dunsyre Blue and therefore the

supply of raw cows’ milk. Since version 2.0 of the risk assessment was finalised,

milk samples have been taken (on 29 September and 19 October) from the farm

supplying cows’ milk to ECL. STEC has been detected in two of these samples,

which provides evidence that the raw cows’ milk may periodically become

contaminated with pathogens. These positive STEC results show that the controls,

identified in ECL’s risk analysis document (annex 10), which have been implemented

to prevent STEC contamination of the incoming raw cows’ milk, are inadequate. The

detection of STEC in the raw cows’ milk also confirms previously published literature

(Farrokh et al., 2012; EFSA 2015) that STEC can occur in raw milk. With regards to

raw cows’ milk, these positive results have reduced the high level of uncertainty

expressed in version 2.0 on whether individual bulk milk samples may contain STEC

and confirms the statement ‘it is likely that over a period of time STEC will be present

in occasional batches of raw milk delivered to ECL’.

ECL has its own flock of sheep which are kept on Errington’s farm and milked on site

in their own milking parlour. The milk from the ewes is used to make Lanark Blue,

Lanark White, Corra Linn and Sir Lancelot cheeses. No milk samples have been

taken from the ewes as they are no longer producing milk. However, similar to raw

cows’ milk, the literature (Farrokh et al., 2012; EFSA 2015) has shown that STEC

can occur in raw ewes’ milk and additionally a study undertaken in 2005 showed that

a range of E. coli strains could be detected in sheep faeces in Scotland (Evans et al.,

2011).

In summary, there is high uncertainty on whether individual bulk ewes’ milk samples

contain STEC. However, since STEC is prevalent in Scottish sheep and there is

Raw milk cheese risk assessment v3.0 08/11/16

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scientific literature which reports that ewes’ milk can be contaminated by STEC, it is

likely (as seen with the cows’ milk) that over a period of time STEC will be present in

occasional batches of ewes’ milk.

5.2 Likelihood of STEC being present at the end of maturation

Version 2.0 remains accurate but predominantly concentrated on the production of

Dunsyre Blue.

The controlling factors (pH, aw and temperature) to prevent the growth and survival

of pathogenic E. coli are clearly documented in version 2.0 and remain the same

regardless of the type of cheese produced. ECL have a generic HACCP document

which covers the production of all six different types of cheese that they produced

(annex 1 version 2.0) and from the documentation the only difference in controlling

factor identified between the different cheeses is the cheesemaking acidity.

The pH for semi-hard cheeses has to be <5.2 the following morning after production,

whilst the lactic ladle curd has to have a pH <4.7. The optimum growth of E. coli

O157 is at pH 7 but it can grow in the range of pH 4.5 to 9. FSS has not received

make sheets for any of the non-blue cheeses and therefore cannot comment on how

the pH changes during the production of the other cheese types. However, the final

pH that is aimed for the morning after production would not by itself prevent the

growth of E. coli O157.

There is no information on the physico-chemical characteristics of the different

cheeses during production and at the end of maturation and end-of-shelf life, or

predictive modelling of pathogen growth or challenge testing for any of the other

cheese types manufactured by ECL. However, the literature has demonstrated that

E. coli O157 can be isolated from a variety of different cheeses including raw milk

hard cheese (Honish et al., 2004). Additionally, STEC has been detected in batches

of Dunsyre Blue and Lanark Blue, which are made from cows’ milk and ewes’ milk

respectively. Furthermore, E. coli O157 has been detected in three different batches

of ewes’ milk Lanark White. This suggests that these organisms can survive the

maturation process for these three different types of cheese or that there was cross-

contamination of the cheeses during maturation.

5.3 Concluding remarks from risk characterisation 5.3.1 Outbreak

Investigation of food histories and product traceability has established an

epidemiological association between an outbreak of E. coli O157 PT21/28, involving

26 human cases, and Dunsyre Blue cheese. HPS are undertaking further statistical

analysis on the epidemiological evidence and this information will be reported in their

final IMT report

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5.3.2 Batch F15 (Dunsyre Blue)

As version 2.0.

In addition, since version 2.0 of the risk assessment a further STEC has been

isolated from batch F15 which has been confirmed by WGS as the exact same strain

as the first isolate (E. coli, O-unidentifiable:H20, stx2d, ST1308). Therefore, the risk

assessment summarised in version 2.0 remains unchanged but now applies to two

samples.

5.3.3 Batch E24 (Dunsyre Blue)

As version 2.0

5.3.4 Batch G12 (Dunsyre Blue)

As version 2.0

5.3.5 Batch G14 (Lanark White)

Two samples of batch G14 (taken on separate dates) of Lanark White cheese made

from unpasteurised ewe’s milk have produced positive results. Both samples

contained a stx negative E. coli O157, which were later shown by WGS to contain

the same organism (E. coli O157:H42 ST P3216 stx negative). The Scottish E. coli

O157/VTEC Reference Laboratory (SERL) have reported that stx gene negative

strains of E. coli O157 have been isolated from cases of human illness consistent

with E. coli O157 infection. Additionally, the Food Examiner at Edinburgh Scientific

Services (ESS) declared the samples to be “potentially injurious to health and/or unfit

for human consumption”. Therefore we would consider this batch of cheese (G14) to

be high risk that the cheese is hazardous to human health. There is a medium level

of uncertainty associated with this estimate due to lack of extensive information on

the pathogenicity of E. coli O157 without stx genes.

5.3.6 Batch H24 (Lanark White)

FSS were notified on 14 September that the stx2 gene had been detected in this

batch as outline in version 2.0. Further confirmatory analysis of this sample showed

it contained a stx gene negative E. coli O157, the same as that found in batch G14

(E. coli O157:H42 ST P3216 stx negative). Therefore, taking in to account the advice

from both SERL and the Food Examiner on the presence of stx negative E. coli

O157 we would consider this batch of cheese (H24) to be high risk that the cheese is

hazardous to human health. There is a medium level of uncertainty associated with

this estimate due to lack of extensive information on the pathogenicity of E. coli

O157 without stx genes.

5.3.7 Batch H3 (Lanark White)

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The same stx gene negative E. coli O157, as found in batches G14 and H24 (E. coli

O157:H42 ST P3216 stx negative) was detected in batch H3. Therefore, taking in to

account the advice from both SERL and the Food Examiner on the presence of stx

negative E. coli O157 we would consider this batch of cheese (H24) to be high risk

that the cheese is hazardous to human health. There is a medium level of

uncertainty associated with this estimate due to lack of extensive information on the

pathogenicity of E. coli O157 without stx genes.

5.3.8 Batch E24 (Lanark Blue)

Batch E24 of Lanark Blue has been found to contain a non-O157 E. coli with the stx2

gene (an STEC). Whole genome sequencing is currently being undertaken at Public

Health England and therefore the serogroup and stx2 subgroup is unknown to

assess this organism’s full pathogenicity. However, a considerable number of non-

O157 STECs have been reported to be pathogenic to humans (70 are listed in the

US by Gould et al., 2013). SERL has also communicated to FSS that a quarter to a

third of their isolates from human cases in Scotland are now non-O157 strains.

Taking into account the literature on the ability of a wide range of non-O157 strains

to cause human illness, the isolation of a non-O157 STEC strain with stx2 (in the

absence of full WGS) in this batch of cheese indicates a high risk that the cheese is

hazardous to human health, however the level of uncertainty associated with this

estimate is medium due to the lack of definitive information on the isolated strain and

its pathogenicity.

5.3.9 Other batches of Dunsyre Blue, Lanark White and Lanark Blue cheese.

As per version 2.0 with regards to the other batches of Dunsyre Blue (and now

Lanark White and Lanark Blue), those that have tested negative for STEC are likely

to have a lower likelihood of STEC being present than batches which have tested

positive. However, negative test results do not guarantee that a product is free from

STEC contamination. STEC may be heterogeneously distributed and could be

present at very low levels in some cheeses making it difficult to detect other than

with extensive sampling and testing. In addition, the production method,

environment and source of milk, is likely to be the same or very similar, for batches

which have tested positive and ones which have tested negative. Importantly, there

does not appear to be any demonstrable evidence of steps in the production which

would eliminate STEC. Thus, the potential for STEC bacteria to be present in

matured cheese remains as demonstrated by the analysis of samples from batch

F15 Dunsyre Blue and Batch E24 Lanark Blue. A greater number of STEC negative

samples from a batch would increase confidence that STEC is not

present. However, statistical advice would be required to establish the number of

samples required for a given level of confidence.

Raw milk cheese risk assessment v3.0 08/11/16

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For those batches that have not been tested, the process of production does not

appear to eliminate STEC (as demonstrated in F15 and E24) so there is a possibility

that STEC could be present in the cheese.

5.3.10 Other batches of ECL cheese.

FSS has very little information or evidence on the other types of cheese produced by

ECL. In total 5 batches of other cheese made by ECL have been sampled and

tested (1 batch of Maisie’s Kebbuck; 3 batches of Corra Linn and 1 batch of Sir

Lancelot). No E. coli or stx genes were detected in any of these 5 samples.

Additionally, FSS has not been provided with any information on the physico-

chemical characteristics of the different types of cheese or predictive modelling

studies of pathogen growth or challenge testing to allow FSS to make an

assessment if the processes in place are adequate to control the growth and survival

of STEC in the product. However, there is evidence that STEC has been detected in

the raw cows’ milk supplied to ECL. Therefore without evidence to the contrary from

ECL on demonstrable steps that would eliminate STEC in the final product and

considering the scientific literature that STEC can be detected in a wide range of

cheese types, we would consider that there is the potential for STEC to be present in

the final matured product.

In summary, E. coli O157, toxin-producing non-O157 strains and presumptive

positives for STEC have been detected in ECL’s raw milk cheeses made from both

cows’ and ewes’ milk, which indicates lack of control for pathogenic E. coli for more

than one production line.

Raw milk cheese risk assessment v3.0 08/11/16

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REFERENCES

EFSA (European Food Safety Authority), (2015). Scientific Opinion on the public health risks related

to the consumption of raw drinking milk. The EFSA Journal 13, 3940.

Evans, J., Knight, H., McKendrick, I.J., Stevenson, H. Barbudo, A. V., Gunn, G. & Low, C. (2011)

Prevalence of Escherichia coli O157 :H7 and serogroups O26, O103, O111 and O145 in sheep

presented for slaughter in Scotland. Journal of Medical Microbiology 60, 653–660

Farrokh C, Jordan K, Auvray F, Glass K, Oppegaard H, Raynaud S, Thevenot D, Condron R, De Reu

K, Govaris A, Heggum K, Heyndrickx M, Hummerjohann J, Lindsay D, Miszczycha S, Moussiegt S,

Verstraete K, Cerf O., (2012) Review of Shiga-toxin-producing Escherichia coli (STEC) and their

significance in dairy production. In J Food Microbiol 162(2) 190-212.

Gould LH, Mody RK, Ong KL, Clogher P, Cronquist AB, Garman KN, Lathrop S, Medus C, Spina NL,

Webb TH, White PL, Wymore K, Gierke RE, Mahon BE, Griffin PM; Emerging Infections Program

Foodnet Working Group. (2013) Increased Recognition of Non-O157 Shiga Toxin–Producing

Escherichia coli Infections in the United States During 2000–2010: Epidemiologic Features and

Comparison with E. coli O157 Infections. Foodborne pathogens and disease, Volume 10, Number 5,

453-460.

Honish, L., Predy, G. Hislop, N. Chui, L., Kowalewska-Grochowska, K. Trottier, L., Kreplin, C., &

Zazulak, I., (2004) An Outbreak of E. coli O157:H7 Hemorrhagic Colitis Associated with

Unpasteurized Gouda Cheese. Revue Canadienne de Santé Publique 96:3 182-184.

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Annex 9: Positive Results from Cheese and Milk Samples.

ESS Lab Number

LA Ref Date sampled

Batch Number

LA sample description

Stx1 Stx2 E. coli WGS result

50425565 46204 23/08/2016 F15 Dunsyre Blue Cheese, Batch F15

-ve +ve Non-O157 E. coli O unidentifiable H20 stx2d ST1308

50426130 046257, Tag 453

29/08/2016 F15 Dunsyre Blue Cheese, Batch F15

-ve +ve Non-O157 E. coli O unidentifiable H20 stx2d ST1308

50426405 046275, TAG 0005

31/08/2016 G14 Lanark White, Batch G14

-ve -ve O157 E. coli O157:H42 ST P3216 stx negative

50427280 046292 - TAG 00447

13/09/2016 G14 Lanark White Cheese - G14

-ve -ve O157 E. coli O157:H42 ST P3216 stx negative

50427273 046285 - TAG 00016

13/09/2016 H3 Lanark White Cheese - H3

-ve -ve O157 E. coli O157:H42 ST P3216 stx negative

50427275 046287 - TAG 0000019

13/09/2016 H24 Lanark White Cheese - H24

-ve -ve O157 E. coli O157:H42 ST P3216 stx negative

50428221 046333 - SM058853

29/09/2016 Bulk milk tank

Milk- Raw Bulk Tank

-ve +ve Non-O157 Awaited

50426402 046272, TAG 0000038

31/08/2016 E24 Lanark Blue, Batch E24

-ve +ve Non-O157 Awaited

50429903 46486 19/10/2016 Raw milk Raw milk +ve +ve Non-O157 Awaited

50426128 046255 Tag 451

29/08/2016 F15 Dunsyre Blue Cheese, Batch F15

-ve +ve N/A

Raw milk cheese risk assessment v3.0 08/11/16

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50426129 046256 Tag 452

29/08/2016 F15 Dunsyre Blue Cheese, Batch F15

-ve +ve N/A

50426131 046258 Tag 455

29/08/2016 F15 Dunsyre Blue Cheese, Batch F15

-ve +ve N/A

50426132 046259 Tag 454

29/08/2016 F15 Dunsyre Blue Cheese, Batch F15

-ve +ve N/A

50426133 046260 Tag 443

29/08/2016 F15 Dunsyre Blue Cheese, Batch F15

-ve +ve N/A

50426134 046252 Tag 457

29/08/2016 F15 Dunsyre Blue Cheese, Batch F15

-ve +ve N/A

50426135 046253 Tag 458

29/08/2016 F15 Dunsyre Blue Cheese, Batch F15

-ve +ve N/A

50426136 046254 Tag 459

29/08/2016 F15 Dunsyre Blue Cheese, Batch F15

-ve +ve N/A

50426163 046238 TAG 474

29/08/2016 G12 Dunsyre Blue Cheese, Batch G12

-ve +ve N/A

50426399 046261, TAG 0000013

31/08/2016 E24 Dunsyre Blue Cheese, Batch E24

-ve +ve N/A

50425867 046221 26/08/2016 E24 Dunsyre Blue Cheese Batch E24

-ve +ve N/A

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Annex 10

HJ Errington & Co

RISK ANALYSIS – PRIMARY PRODUCTION OF RAW MILK

Although HACCP in Primary Production is not yet a legal requirement (preamble 852/2004), the manufacture of

raw milk cheeses is dependent upon strict pathogen control in husbandry practices and during milking and the

reduction of risk in the development of Staphylococcus aureus toxin

PRO CESS

STEP

PO TENTIAL

HAZARD

RISK ANALYSIS PREREQ UISITE CO NTRO L

MEASURES

Additional

Comments

Grazing

E coli 0157

Campylobacter

Salmonella

Giagardia

Cryptosporidium

Faecal deposits from birds, rodents, other

wildlife and muckspreading on grazing areas.

Too high cow population on area of grass –

faecal-oral route.

Resident & high population of pests.

Risk increases if land is near haylage bails,

landfill skips or meat/poultry processing

plants.

LO W Grazing on fields cut for silage

only and out of season

Solids to arable & liquid to

lagoon.

Ratio- animals to land area &

land rotation

Control of rodent and bird pests,

usually absence of feedstuffs to

attract and elimination of nest

sites.

See SCA

Code of

Practice

Dioxins, PCBs

(plastic waste with

carcinogens),

radiation

Carcinogens from breakdown petrochemical

products. High risk if ---- located near

incinerator site

- located near nuclear power plant

- spillages eg. road tanker accidents, refinery

incidents.

V LO W N/A Ref:

dioxins in

Bolsover in

Derbyshire

1993

See ‘New

Scientist’

articles

Pesticide, herbicide

residues

Spraying nitrates & fertilisers.

Down wind of spraying. V LO W Sheep housed until end of season

Drinking

Water

Pathogens

Spring water LO W

Water Authority Analysis Report

In house testing

Water

Authority

analysis Dioxins, pesticides, PCBs,

Radiation

Heavy metals eg.

manganese

Silage Listeria spp

Clostridium

Bacillus

Poor acid devpt , moisture and soil

Sporeforming, psychrotrophic bacteria in soil

contaminating cut and stored silage. Can

survive fermentation process.

Clostridium is a poor competitor against lactic

acid-producing bacteria.

Most probable, but still rare, is non-pathogenic

C butyricum (spoilage only – gas holes & poor

flavours)

LO W Reduction of soil in cut and

stored silage.

Prevention of secondary

fermentation.

.

Face of silage must be clean

before use or the front is

removed.

E coli 0157

& 026

Bird faeces in or on silage Sheeted and netted (adequately

covered) and not located near

waste matter which may attract

them to the vicinity

Ref 026 in

Raw milk

Camembert

, France,

2006

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15

Bought-in

Feed-

(list)

Antibiotics

Supplied by reputable supplier

(currently [name])

Analysis can be provided.

LO W Animal Feedstuffs Regulations

PCBs etc

Pesticides,

herbicides

Mycotoxins from mouldy cereals

AnimalBy-Products Regs

1774/2002

GM

Infected animal by-

products

Feed Storage Pathogens, urine &

faeces from vermin

during storage

V LO W Pest Control contract.

Stored in closed bins/silos.

Turnover of stocks.

Removal of redundant stocks.

Animal

Health-

general

Mycobacterium sp.

avium

paratuberculosis

Linked with Johne’s disease in cattle

(prevalent in Jersey breed) and Crohne’s

disease in humans. No scientific conclusive

evidence for that link, the transmission

through milk or destruction by pasteurisation.

Awaiting

further

research

Associated with bird faeces – see

‘Grazing’

Mycobacterium

tuberculosis

Sheep

N/A EC/853/2004 Section

IX.Ch.1.1.2b.

DEFRA & veterinary checks 12-

monthly) Do not make raw milk cheese

with milk from suspect herd.

Brucella

melitensis/aborti

Negligible risk if milk from a Brucellosis –

free herd (DEFRA)

V LOW EC/853/2004 S.1X. Ch 1.1.2.a

Bovine spongiform encephalopathy

No evidence of transmission to humans through milk.

V LOW Animal Feed Regs

Foot & Mouth virus

Destroyed by lactic acid and caustic solutions.

Not transmitted through fermented products.

LOW EC/853/2005 S.1X. Ch 1.1.1 Ref Meat

Hygiene

Service reference

books.

Animal

health –

digestive

tract

Salmonellae spp

Destroyed by lactic acid in matured cheese. As

blue and moulds develop acididty increases

therefore risk decreases

LOW EC/853/2005 S.1X. Ch 1.1.1

Diarrhoea

‘New

Scientist’

article

E coli 0157

Some cows are carriers.

Mostly associated with calves.

Can be eliminated by increased roughage in

the feed, eg hay, barley. and more solid faeces

LOW/

MED risk

in U/P hard

cheese

Animal

health –

udders

Mastitis caused by

Staphylococcus

aureus

E coli 0157

Can be transmitted by humans

Can be present with no clinical signs

Toxin is produced above 10°C and is heat

stable.

Udder with discharge and swelling.

Blood/clots in foremilk

LOW/

MED risk

in U/P hard

cheese

EC/853/2005 S.1X. Ch 1.1.1

Hand washing (II.C)

Somatic Cell Counts

Geometric average:

< 400,000 /ml (853/2004)

(1X.III. 3.a)

Visual inspection of udders.

‘Red flag’ control

Listeria

monocytogenes

Environmental. Ensure clean udders especially

in wet & windy conditions

Good milking hygiene prevents cross-

contamination onto udder from faeces

LOW

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16

Destroyed by pasteurisation and lactic acid in

matured cheese

Antibiotic residues Minute traces may be present despite PASS

results. Very low probability of occurrence but

traces may induce anaphylactic reaction to

vulnerable consumers, esp beta-lactams or

penicillin types.Can dilute in large bulk tanks.

Would generally cause starter failure. If make

is successful, most A/Bs are associated with

whey phase.

Some ‘drying off’ drugs may associate with the fat phase.

We have never had a possibtive test due to

dedicated suppliers

V LOW

In

Cheese

Low in

milk

EC MRLs set in 2377/90 & EC

853/2004 (!X.4 a&b)

Raw milk checks with Delvotest

SP test once per month

Occurrence

s in 2006:

None

since1/1/20

02

MILKING

PARLO UR

Smashed glass

Metal fragments or

swarf

V. Serious implications for injury but

negligible risk of occurrence because of in-

line filters

LOW

Farm Assurance schemes

including Glass Policies.

In-line filters

- ex-bulk tank

- tanker

- milk intake line

- pasteurisers

Centrifugal separation

Pest Matter

See Feed Storage MED Maize stored ½ mile from farm Ecolab

contract

Phenolic type

chemical taints

(eg. Jeyes Fluid,

Dettol, flysprays,

paints, wood

preservatives, solvents, glues, non-

food grade plastics)

Considered low by the industry but DDS knows of frequent

unpublicised occurrences,plus ref to Pickerings Dairy circa

1992 causing chemical food poisoning/ hospitalisation of

consumers in Liverpool from contaminated liquid milk.

Significant proportion of the population genetically unable to

taste these chemicals . Can cause illness in all population

categories with disastrous consequences for subsequent dairy operations. Possibility of unsuccessful decontamination

measures.

LOW

Prohibited use for any

application in or around the

milking parlour area

Iodine taints Cleaning of equipment now commonly caustic.

Approved teat dips only LOW

EC/853/2004

Milking

Equipment

clusters and bulk tanks

Survival and growth

of pathogen

contamination

through poor cleaning, milkstone &

contaminated water

ITEM MAINTENANCE/CLEAN CO NTRO L MEASURES

Vacuum 6-monthly plant test

(No jars)

O rings, seals,rubbers

Pipework 6 monthly inspection

Bulk Tanks Service contract with Noblet Refrigeration and callout. (Main

Office)

GENERAL CLEANING SCHEDULE Chemical: Sodium Hydroxide (caustic) 600gms in 80 galls. (Single use)

CirculationTemp: not less than 75 deg C throughout T ime:

not less than 5 mins, then cold rinse 5 mins

Supplementary Manual cleans as required

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Bulk Tanks Growth of

Mesophilic Pathogens , viz

Salmonellae

S aureus, &

development of S

aureus toxins

Prevent introduction of these with

control measures detailed above.

S aureus toxin develops above 10 deg

C

LOW EC/853/2004

- cool to < 8° C for

daily use/collection - cool to <6° C for not

daily collection

- to reach dairy bulk

tanks at not more than

10° C

Listeria

monocytogenes

E Coli 0157

Clostridium

Bacillus

Will grow at chill temps.

Best prevented by previously listed

control measures

LOW -