One of the primary concerns regarding safe seafood in the aquaculture sector is bivalve molluscs, which are usually delivered to the consumer alive and can selectively retain contaminants that are harmful to human health.
Classification of harvesting areas
Controls are in place to substantially reduce the risk posed by live bivalve molluscs. European Hygiene Regulations, which came into force in January 2006, state that culturists must meet strict food safety standards, and the FSA has classified harvesting areas and beds from which shellfish are gathered, based on the presence of E.coli in the mollusc flesh:
- Class A grounds mean that mollusc flesh has less than 230 cfu's of E.coli per 100g of flesh. Molluscs may be sent straight to the market without any intervention.
- Class B grounds mean that mollusc flesh has between 230 and 4,600 cfu's per 100g of flesh. Molluscs must be relayed to cleaner waters and purified thorugh an approved dapuration unit or heat-treated before they can be sold for human consumption.
- Class C grounds means that flesh has between 4,600 and 46,000 cfu's per 100g of flesh. Molluscs must be relayed to designated cleaner waters for a minimum of two months, or purified, or heat-treated, in order to meet Class A or Class B standards.
- Prohibited areas mean that molluscs cannot be harvested for human consumption.
Most UK mollusc harvesting areas are class B, which means that the molluscs must be purified before being sold to consumers. All molluscs sold on the UK market must have less than 230 cfu's of E.coli per 100g of flesh.
Delivering safer seafood
Controls are in place to mitigate against potential contamination of bivalve molluscs. To ensure best practice guidelines are followed Seafish has produced a series of industry guidance notes for fishers and shellfish farmers.
- Paralytic Shellfish Poisoning
- Amnesic Shellfish Poisoning
- Norovirus in live bivalve molluscs
- Anisakis in salmon
Seafish have also produced the Good manufacturing practice guidelines: Live bivalves workbook. This is a step-by-step guide to good live bivalve preparation for the market. See Appendices 2 and 3 for EPT standards.
A number of Seafish guidance notes about harvesting areas and bivalve purification can be found here.