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6 SEAFOOD SAFETy 



Natural seafood toxins -mainly ciguatera and scombroid poisoning and, to a 

 lesser extent, paralytic shellfish poisoning -were responsible for 62.5% of all seafood- 

 borne outbreaks of illness, but constituted only 28% of all reported cases. Shellfish- 

 related incidents, although responsible for only 31% of the seafood illness outbreaks, 

 involved 66% of all seafood-borne cases. Most of these (55%) were registered as of 

 unknown etiology but are believed to be due mainly to Norwalk, Norwalk-like, or 

 human enteric virus infections, with a smaller proportion caused by Vibrio bacteria. 

 Fish-borne incidents due to causes other than natural toxins were only 9% of all 

 outbreaks and 8% of all cases. They resulted mainly from bacteria, including common 

 food-borne disease organisms, and from unknown etiology, suspected to be primarily 

 enteric virus or recontaminant vibrios. Botulism is a specialized but significant 

 component of fish-bome disease. Disease due to parasites was minimal (0.4% of 

 outbreaks and 0.6% of cases reporied from seafoods). 



Shellfish-bomc disease occurs mostly from molluscs consumed raw or lightly 

 heated, which constitutes the largest consumer risk. Ciguatera is a highly regionalized 

 and intense risk for inhabitants and visitors consuming certain reef-associated fish in 

 Caribbean and tropical Pacific islands and in adjacent mainland areas. Scombroid 

 poisoning is widely distributed geographically but is specifically associated with 

 consumption of certain fish species, particularly tuna, mackerel, mahimahi (dolphin), 

 and bluefish. Botulism is a hazard for native American groups in Alaska that eat 

 traditional fermented seafoods. Other risks are typical of food-borne disease in general 

 and result from errors in handling, storage, or processing procedures. These are no 

 greater than for other foods of animal origin. 



Intolerance to eating cenain types of seafood is rare and more typically 

 associated with certain individuals in risk categories predisposed by other health 

 complications. Seafood allergies, distinguished as immunological reactions rather than 

 the inability to digest, appear to be more prevalent, but they are difficult to diagnose 

 and document. Specific allergens in seafood have thus far been only grossly 

 characterized in few studies. Seafood intolerances and allergies can be due to food 

 additives (e.g., sulfites) that cause symptoms and confuse diagnoses. Additional 

 investigation of the biochemical and immunological characteristics of seafood allergies 

 and their significance seems warranted. In light of this level of information on the 

 cause and occurrence of this somewhat limited form of seafood-borne illness, regulatory 

 response must depend on proper labeling to distinguish (1) species or seafood type, 

 (2) ingredients in formulated and fabricated seafoods [e.g., fish base surimi (a washed 

 mince of the separated muscle tissue from fish to which cryoprotectants are added) 

 formed to resemble crab], and (3) ingredients used in preservation and processing (e.g., 

 sulfites to retard shrimp melanosis). 



Microorganisms and Parasites 



Extent of Risk 



Seafoods, like any food item, have the potential to cause disease from viral, 

 bacterial, and parasitic microorganisms under cenain circumstances. TTiese agents are 

 acquired from three sources: (1) mainly fecal pollution of the aquatic environment, (2) 

 the natural aquatic environment, and (3) industry, retail, restaurant, or home processing 



