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Introduction and characterization of hazards in seafood

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Title: Introduction and characterization of hazards in seafood


1
Introduction and characterization of hazards in
seafood
Quality 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
2
Contents
  • Food borne hazards
  • biological hazards
  • chemical hazards
  • physical hazards
  • Preventive measures

3
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

4
Hazards
  • Biological
  • pathogenic bacteria
  • viruses
  • worms
  • helminths
  • protozoa

Chemical histamine
heavy metals pesticides
antibiotics
dyes
mycotoxin
  • Physical
  • bolts and nuts
  • metal fragments
  • sand

5
Bacteria
These organisms may cause diseases- mild
gastroenteritis to severe and sometimes fatal
dysentery, cholera or typhoid
Faecal pollution - drinking water and sea
water
6
The size of a bacteria 5 cm bacteria 8,5 km man
7
Bacteria multiply by binary fission One
bacterium can multiply to one hundred million in
only nine hours
Growth of bacteria
8
Harmful microorganisms
  • They can cause
  • Illness
  • Food spoilage
  • Spoilage of e.g. wood, iron

9
Pathogenic bacteria in seafood/aquatic food
  • Aquatic environment Vibrio spp.
  • Clostridium botulinum Type E
  • (non-proteolytic)
  • Aeromonas
  • Plesiomonas
  • General environment Listeria
    monocytogenes
  • Clostridium botulinum Type A,B (proteolytic)
  • C. perfringens
  • Bacillus cereus
  • Animal-human reservoir Salmonella
  • E. coli (EPEC, ETEC, EHEC)
  • S. typhi
  • Staphylococcus aureus
  • Shigella

10
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)

11
Parasites
  • Numerous different types of parasites exist
    worldwide, but only about 100 types are known to
    infect people through food contamination
  • parasitic worms
  • protozoa

12
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

13
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

14
Protozoa
  • About 40 sp. of parasitic protozoans are known to
    be infectious to humans
  • Cryptosporidium parvum
  • Entamoeba histolytica
  • Giardia lamblia
  • Cyclospora sp.

15
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

16
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

17
Chemical hazards - examples
  • food additives
  • veternary drugs residues
  • pesticides
  • natural toxicants
  • mycotoxins, biotoxins
  • Histamine
  • environmental contaminants
  • mercury, lead, cadmium, arsenic,
  • dioxins

18
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

19
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)

20
Chemical hazards
chlorinated phosphate aldrin/deldrin phos
pholidon malathion parathion diazinon fertilizers
Pesticides
21
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

22
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,
  •  

23
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

24
Natural marine toxins
  • Scombrotoxin
  • Ciguatoxin ciguatera from marine algae - gt400
    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
25
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

26
Scombrotoxin Biogenic 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 TC gt5C, pH 4.7-8.1, salt lt5
  • Symptoms
  • mild disease facial flushing, urinary problems
  • gastrointestinal and neurological disorder.
  • Symptoms last only for few hours and recovery is
    complete

27
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
    recorded
  • CCP-chilling shortly after catching and killing
  • the time to decrease the temperature below 10C
    should not exceed 2 h.
  • Good hygienic practices on-board, at landing and
    during processing

28
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

29
Controlling physical hazards
  • GMPs
  • Ingredient specifications
  • Supplier certification
  • Use equipment to screen for physical hazards
  • Employee training

30
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 Laboratories
  • WHO 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
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