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