Dar seafood ppp standard

Likelihood of adverse health effects for cooked product

Oysters and other bivalves, when not eaten raw, are usually only lightly cooked or steamed before consumption. In this report, it has been assumed that this cooking would normally be sufficient to reduce bacterial hazards to low levels. However, enteric viruses are significantly more heat resistant than bacterial pathogens and infectious doses are assumed to be very low, hence it is considered unlikely that cooking will effectively reduce them to safe levels. Algal biotoxins are also very heat stable [41,42].

Relative risk ranking for oysters and other bivalves – conclusions

The severity and likelihood of adverse health effects due to specific hazards associated with oysters and other bivalves are combined in Table 6 to provide relative risk rankings for those hazards. It is concluded that the overall public health risk for this commodity group is relatively high for product harvested in polluted waters and/or waters not subject to a monitoring scheme such as ASQAP, based on the potential presence and adverse health effects of hepatitis A virus and algal biotoxins. The ranking is high due to those algal biotoxins with ‘severe’ adverse health effects (that is, amnesic shellfish poison and paralytic shellfish poison), while it is medium for those rated as having ‘serious’ adverse health effects (that is, diarrhoetic shellfish poison and neurotoxic shellfish poison – these are not included in Table 6). The relative risk ranking is not significantly reduced where these products are cooked prior to consumption.

When the implementation of shellfish safety management schemes, such as ASQAP, is taken into account, the relative risk ranking for oysters and other bivalves is reduced to medium.

The overall relative risk ranking for product eaten raw is also high for people who are susceptible to primary septicaemia from V. vulnificus infection (that is, people with liver dysfunction or high serum iron levels).