introduction and characterization of hazards in seafood quality and safety issues in fish handling...
TRANSCRIPT
Introduction and characterization of hazards in
seafoodQuality and safety issues in fish handling
-----A course in quality and safety management in
fishery harbours in Sri Lanka NARA, DFAR, ICEIDA and UNU-FTP
Icelandic International Development Agency (ICEIDA)
Iceland
United Nations University Fisheries Training Programme (UNU-FTP)
Iceland
National Aquatic Resources Research and Development Agency (NARA)
Sri Lanka
Department of Fisheries and Aquatic Resources (DFAR)
Sri Lanka
Contents
• Food borne hazards• biological hazards• chemical hazards• physical hazards
• Preventive measures
Learning objectives
After this lecture participants will be familiar with:• food borne hazards and routes of contamination
• how to prevent that fish from being contaminated
Hazards
Physicalbolts and nuts
metal fragments
sand
Biological
pathogenic bacteriaviruseswormshelminthsprotozoa
Chemical
histamine heavy metals pesticides antibiotics dyes mycotoxin
Bacteria
Faecal pollution - drinking water and sea water
These organisms may cause diseases- mild gastroenteritis to severeand sometimes fatal dysentery, cholera or typhoid
The size of a bacteria5 cm bacteria = 8,5 km man
Bacteria multiply by binary fissionOne bacterium can multiply to one hundred million in only nine hours
Growth of bacteria
Harmful microorganisms
They can cause:• Illness
• Food spoilage
• Spoilage of e.g. wood, iron
Pathogenic bacteria in seafood/aquatic food
• Aquatic environment Vibrio spp.
Clostridium botulinum Type E (non-proteolytic)AeromonasPlesiomonas
• General environment Listeria monocytogenes
Clostridium botulinum Type A,B (proteolytic)C. perfringensBacillus cereus
• Animal-human reservoir Salmonella
E. coli (EPEC, ETEC, EHEC)S. typhiStaphylococcus aureusShigella
Factors affecting bacterial growth(Preventive measures)
•Cleaning and sanitation
•Personal hygiene
•Heat (chilling, super chilling, freezing, canning, pasteurizing)
•Water activity aw ( drying, salting)
•pH (e.g. fermentation, organic acids)
•Preservatives (e.g. benzoic and ascorbic acids)
•Radiation
•Other (MAP, VP)
Parasites
• Numerous different types of parasites exist worldwide, but only about 100 types are known to infect people through food contamination• parasitic worms• protozoa
Pathogenic parasites transmitted by seafood
• raw uncooked fish products
• Nematodes (round worms
• Anisakis simplex - herring
• Angiostrongylus spp. -freshwater prawns, snails, fish
• Pseudoterranova dicipiens (cod worm)
• Cestodes (tape worms)
• Diphyllobothrium latum - fresh water
• D. pacificum - seawater
• Trematodes or flukes
• Paragonimus-snails, crustaceans, fishes (lung flukes)
• Clonorchis spp. – fresh water fish (liver flukes)
• Opisthorchis spp.- fresh water fish
Prevention and control of trematode
• The WHO Technical Report on trematode infections details basic strategies for the control of fish-borne trematode infections
• Trematodes are more resistant to heat and salt than nematodes
• Control programmes involve• detection and treatment• health education• improved sanitation• legislation of food safety measures• management of human faeces• HACCP
Protozoa
• About 40 sp. of parasitic protozoans are known to be infectious to humans• Cryptosporidium parvum• Entamoeba histolytica• Giardia lamblia• Cyclospora sp.
Prevention and control
• Good personal hygiene
• Proper sanitation of toilets seats
• Avoid eating raw fruit and vegetables
• Treatment of drinking water• slow sand filtration combined with chemical
flocculation
Prevention and control
• Good personal hygiene
• Proper sanitation of toilets seats
• Avoid eating raw fruit and vegetables
• Treatment of drinking water• slow sand filtration combined with chemical
flocculation
Chemical hazards - examples
• food additives• veternary drugs residues• pesticides• natural toxicants
• mycotoxins, biotoxins
• Histamine• environmental contaminants
• mercury, lead, cadmium, arsenic,
• dioxins
Chemicals hazards, cont.
• agricultural chemicals• e.g. pesticides, fungicides, herbicides, fertilizers,
antibiotics and growth hormones
• prohibited substances • others
• e.g. lubricants, cleaning compounds, sanitizers, paint
Major contaminants/pollutants of concern for harbour managers
• Suspended solids (clay, airborne particulates from industry and plankton etc.)
• Biodegradable organics ( proteins, carbohydrates and fats) Pathogens
• Nutrients (Nitrogen, phosphorus and carbon) Priority pollutants (highly toxic chemicals)• Refractory organics (pesticides, phenols, surfactants) Heavy metals
• Dissolved inorganic chemicals (irritant)
chlorinated phosphate
aldrin/deldrinphos pholidon
malathion parathiondiazinon fertilizers
Pesticides
Chemical hazards
Pollutants
Metal contamination can be from natural sources or from acute or chronic pollution.
• mercury in its organic form –methylmercury• Inorganic mercury can be methylated by biological
(microbiological) processes in aquatic environments• more than 95% of the total mercury content in edible fish tissue is in the
form of methylmercury
• Bioaccumulation in the food chain • highest concentrations are found in predatory fish
• High pH, increased hardness and high content of soluable and suspended organic compounds - conditions that often prevail in pond aquaculture - reduce mercury uptake.
• farmed fish usually harvested young – low level
Organic pollutants
• use of polluted water supplies – chronic contamination from agricultural or industrial chemicals • chlorinated compounds• DDT-dichlorodipheniltrichloroethane, dieldrin, lindane
(insecticides)• polychlorinated biphenyls (PCB) ,• dioxin like PCBs,
Controlling chemical hazards
• Use approved chemicals• specifications
• Maintain chemical inventory• Storage procedure• Conduct audits of:
• use of chemicals• employee practices
• In house training for all employee• Stay updated on regulations and emerging
concerns
Natural marine toxins• Scombrotoxin
• Ciguatoxin – ciguatera from marine algae - >400 fish spp.
• Shellfish toxins• Amnesic shellfish poisoning (ASP)/domoic acid
poisoning
• Diarrhetic shellfish poisoning (DSP)
• Neurotoxic shellfish poisoning (NSP)
• Paralytic shellfish poisoning (PSP)
• Other marine toxins• Tetrodotoxin - About 80 species of puffer fish, blowfish
or fugu• Gempylotoxin -Gemplids, escolars or pelagic mackerels
(escolar; oilfish, castor oil fish or purgative fish; snek)
• Tetramine
marine algae – filter feeding shellfish
Control of disease caused by biotoxins
• cannot be entirely prevented• extremely stable: cooking, smoking, drying,
salting, does not destroy them• depuration and ozonationare not effective
• major preventive measures is:• inspection, sampling from fishing areas and
shellfish beds and analysis for toxins
ScombrotoxinBiogenic amines: Histamine
•Scombroid fish poisoning - Histamine poisoning most common form of toxicity caused by the ingestion of fish
Source: Tuna, mackerel, bonita, mahi mahi(Dolphinfish),Growth T°C >5°C, pH 4.7-8.1, salt <5%Symptoms
mild disease: facial flushing, urinary problemsgastrointestinal and neurological disorder. Symptoms last only for few hours and recovery is complete
Control of scombroid poisoning
• Storage below 5 °C at all times• inform the fishermen and processors of the importance of storage
at low temperature
• sampling and analysis of potentially hazardous species with respect to histamine level
• HACCP temperature/time factors easily measured and recordedCCP-chilling shortly after catching and killing
• the time to decrease the temperature below 10°C should not exceed 2 h.
• Good hygienic practices on-board, at landing and during processing
Physical hazards• glass
• utensils, bottles windows, lights
• metal• equipment, wire,
employees
• stones• fields, buildings
• wood• fields, pallets, boxes,
buildings
• plastic• packaging materials,
pallets, boxes
• bone• fish - improper
processing
• insulation• building material
• personal effects• jewellery
• cigarettes
• hair
• paper flaked paint
Controlling physical hazards
• GMP´s
• Ingredient specifications
• Supplier certification
• Use equipment to screen for physical hazards
• Employee training
References• Huss, H.H., Ababouch, L. and Gram, L. (2004). Assessment and
management of seafood safety and quality. FAO Fisheries technical paper 444.
• Training material from UNU-FTP/Icelandic Fisheries LaboratoriesWHO Technical Report Series, No. 883, 1999. Food safety issues associated with products from aquaculture
• International Commission on Microbial Specification for Foods (1996). Microorganisms in Foods. 5. Microbiological specifications of food pathogens. Blackwell Scientific Puplications.
• Website: http://www.seafood.ucdavis.edu • Lehane and Olley (2000). Histamine fish poisoning revisited. Int.
Journal of Food Microbiol. 58, 1-37