Introduction and characterization of hazards in se……

1、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)IcelandUnited Nations University Fisheries Tr

2、aining Programme (UNU-FTP) IcelandNational Aquatic Resources Research and Development Agency (NARA) Sri LankaDepartment of Fisheries and Aquatic Resources (DFAR) Sri LankaContents Food borne hazards biological hazards chemical hazards physical hazards Preventive measuresLearning objectivesAfter this

3、 lecture participants will be familiar with: food borne hazards and routes of contamination how to prevent that fish from being contaminatedHazards Physicalbolts and nutsmetal fragmentssandBiologicalpathogenic bacteriaviruseswormshelminthsprotozoaChemicalhistamine heavy metals pesticides antibiotics

4、 dyes mycotoxinBacteriaFaecal pollution - drinking water and sea waterThese organisms may cause diseases- mild gastroenteritis to severeand sometimes fatal dysentery, cholera or typhoidThe size of a bacteria5 cm bacteria = 8,5 km manBacteria multiply by binary fissionOne bacterium can multiply to on

5、e hundred million in only nine hoursGrowth of bacteriaHarmful microorganismsThey can cause: Illness Food spoilage Spoilage of e.g. wood, ironPathogenic bacteria in seafood/aquatic food Aquatic environment Vibrio spp.Clostridium botulinum Type E (non-proteolytic)AeromonasPlesiomonas General environme

6、nt Listeria monocytogenesClostridium botulinum Type A,B (proteolytic)C. perfringensBacillus cereus Animal-human reservoirSalmonella E. coli (EPEC, ETEC, EHEC)S. typhiStaphylococcus aureusShigellaFactors affecting bacterial growth(Preventive measures)Cleaning and sanitationPersonal hygieneHeat (chill

7、ing, super chilling, freezing, canning, pasteurizing)Water activity aw ( drying, salting)pH (e.g. fermentation, organic acids)Preservatives (e.g. benzoic and ascorbic acids)RadiationOther (MAP, VP) Parasites Numerous different types of parasites exist worldwide, but only about 100 types are known to

8、 infect people through food contamination parasitic worms protozoaPathogenic parasites transmitted by seafoodraw uncooked fish products Nematodes (round worms Anisakis simplex - herring Angiostrongylus spp. -freshwater prawns, snails, fish Pseudoterranova dicipiens (cod worm) Cestodes (tape worms) D

9、iphyllobothrium 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 fishPrevention and control of trematode The WHO Technical Report on trematode infectio

10、ns 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 HACCPPro

11、tozoa 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

12、 slow sand filtration combined with chemical flocculationPrevention 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 flocculationChemical hazards - examples food additive

13、s 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

14、 substances others e.g. lubricants, cleaning compounds, sanitizers, paintMajor 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 (Nitrog

15、en, phosphorus and carbon) Priority pollutants (highly toxic chemicals) Refractory organics (pesticides, phenols, surfactants) Heavy metals Dissolved inorganic chemicals (irritant)chlorinated phosphatealdrin/deldrinphos pholidonmalathion parathiondiazinon fertilizersPesticidesChemical hazardsPolluta

16、nts 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

17、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

18、harvested young low levelOrganic 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 chemi

19、cal 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 concernsNatural marine toxinsScombrotoxinCiguatoxin ciguatera from marine

20、 algae - 400 fish spp.Shellfish toxinsAmnesic shellfish poisoning (ASP)/domoic acid poisoningDiarrhetic shellfish poisoning (DSP)Neurotoxic shellfish poisoning (NSP)Paralytic shellfish poisoning (PSP)Other marine toxinsTetrodotoxin - About 80 species of puffer fish, blowfish or fuguGempylotoxin -Gem

21、plids, escolars or pelagic mackerels (escolar; oilfish, castor oil fish or purgative fish; snek)Tetraminemarine algae filter feeding shellfishControl of disease caused by biotoxins cannot be entirely prevented extremely stable: cooking, smoking, drying, salting, does not destroy them depuration and

22、ozonationare not effective major preventive measures is: inspection, sampling from fishing areas and shellfish beds and analysis for toxinsScombrotoxinBiogenic amines: HistamineScombroid fish poisoning - Histamine poisoning most common form of toxicity caused by the ingestion of fishSource: Tuna, ma

23、ckerel, bonita, mahi mahi(Dolphinfish),Growth TC 5C, pH 4.7-8.1, salt 5%Symptomsmild disease: facial flushing, urinary problemsgastrointestinal and neurological disorder. Symptoms last only for few hours and recovery is completeControl of scombroid poisoning Storage below 5 C at all times inform the

24、 fishermen and processors of the importance of storage at low temperature sampling and analysis of potentially hazardous species with respect to histamine level HACCPtemperature/time factors easily measured and recordedCCP-chilling shortly after catching and killing the time to decrease the temperat

25、ure below 10C should not exceed 2 h. Good hygienic practices on-board, at landing and during processingPhysical 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 pe