increasing. This trend seems to be due in part to the food safety control measures mandated since 1997 (e.g., HACCP and monitoring of sanitation control procedures); the new labeling requirements providing educational support; and specific management plans implemented by regulatory and industry partnerships to address the more serious illnesses associated with consumption of raw molluscan shellfish. However, the potential for misuse of chemotherapeutants in domestic and imported aquaculture products is a source for concern about the presence of toxins and increased antimicrobial resistance in seafood, particularly in light of increasing dependence on aquacultured products.
The committee’s review of evidence on risks associated with consumption of seafood drew on current research reports and reviews, published reviews from stakeholder groups, invited presentations made to the committee, and correspondance with experts in areas relevant to the statement of work. One component of the committee’s charge was to identify and prioritize the potential for adverse health effects from both naturally occurring and introduced toxicants in seafood. The conclusion from the committee’s review of evidence is that, among chemical contaminants, methylmercury presents as a greater concern for adverse health effects, whereas the risk associated with dioxins and PCBs in seafood remains uncertain due to both the availability of evidence and the strength of the findings, and that microbial hazards, particularly those associated with handling and cooking practices, pose a more controllable yet persistent seafood-related risk from the standpoint of public health concerns.
Levels of contaminants in seafood depend on several factors, including species, size, harvest location, age, and composition of feed. Methylmercury is the seafoodborne contaminant for which the most exposure and toxicity data are available; levels of methylmercury in seafood have not changed substantially in recent decades. Exposure to dioxins and PCBs varies by location and vulnerable subgroups (e.g., some American Indian/Alaskan Native groups living near contaminated waters) may be at increased risk. Microbial illness from seafood is acute, persistent, and a potentially serious risk, although incidence of illness has not increased in recent decades.
Methylmercury is the seafoodborne contaminant for which the most comprehensive exposure and toxicity data are available for the purpose of deriving quantitative estimates of the risks.