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EXECUTIVE SUMMARY 7 



and preparation. With the exception of foods consumed raw, however, the reported 

 incidences of seafood-related microbial diseases are low. 



Available data from CDC and from the Northeast Technical Support Unit 

 (NETSU) of the Food and Drug Administration (FDA) for 1978-1987, as well as 

 literature reports, suggest that the greatest numbers of seafood-associated illnesses arc 

 from raw moUuscan shellfish harvested in waters contaminated with raw or poorly 

 treated human sewage. The majority of these illnesses have unknown etiologies 

 clinically suggestive of Norwalk and Norwalk-like agents that cause human viral 

 gastroenteritis. Although these are the most common seafood-associated illnesses, they 

 tend to be relatively mild with no associated mortality. 



Except for Guam, naturally occurring marine Vibrio species are responsible for 

 fewer reported cases of infections involving the consumption of raw molluscan shellfish, 

 but certain species such as V. vulnificus can be associated with high mortality (>50%) 

 in persons who are immunocompromised or who have underlying liver disease. 



The microbiological risk associated with seafood other than raw molluscan 

 shellfish is much lower and appears to result from recontamination or cross- 

 contamination of cooked with raw products, or to contamination during preparation 

 followed by time/temperature abuse (e.g., holding at warm temperature long enough 

 for microbial growth or toxin production to occur). This occurs mainly at the food 

 service (postprocessing) level, which is common to all foods and not specific for 

 seafood products. 



Seafood-related parasitic infections are even less common than bacterial and 

 viral infections, with anisakids and cestodes having the greatest public health 

 significance in the United States. In general, parasitic infections are concentrated in 

 certain ethnic groups that favor the consumption of raw or partially cooked seafoods. 



Thorough cooking of seafood products would virtually eliminate all microbial and 

 parasitic pathogens. Individuals who choose to eat raw seafood should be educated 

 about the potential risks involved and how to avoid or mitigate them. In particular, 

 immunocompromised individuals and those with defective liver function should be 

 warned never to eat raw shellfish. 



The greatest risks from the consumption of raw molluscan shellfish could be 

 minimized by research to develop valid human enteric virus indicators for the proper 

 classification of shellfish growing waters; by implementing and maintaining proper 

 treatment and disposal of sewage to avoid human enteric pathogen contamination of 

 harvest areas; by efforts to identify and limit the number of pathogenic Vibrio species 

 in shellfish; by developmg new diagnostic methods and improved processing 

 technologies; and by applying risk-based regulatory and control measures for potential 

 microbial pathogens in raw molluscan shellfish. 



Other seafood-associated risks can be reduced by proper application of a 

 Hazard Analysis Critical Control Point (HACCP) system. This cannot be achieved by 

 the visual or organoleptic inspection currently used for meat and poultry. Seafood 

 inspection should be directed toward identification of microbiological risks to consumers 

 and the effectiveness of methods to reduce or eliminate such risks. Additional studies 

 are necessary to determine levels of particular microorganisms that constitute a risk 

 and that can be used as a basis for microbial guidelines. This requires appropriate 

 epidemiological research. Inspection requirements should apply to imported as well 

 as domestic products. 



