Scientific Alert Note

Public health risks associated with contaminated shellfish

A document summarising the current control measures and highlighting technical developments in the control of the public health risks associated with sewage-contaminated bivalve shellfish, such as oysters and mussels, has been produced and is available on the SEAFOODplus website. The document draws on information produced from the SEAFOODplus project and other sources and should prove useful to all stakeholders, including industry and regulators, involved in the production of safe shellfish.

 

 

Author: Bill Doré, Marine Institute, Ireland

 


 

Sampling oysters for virus levels during the REDRISK project

Information about the current control measures, and highlighting technical developments in controlling the public health risks associated with sewage-contaminated bivalve shellfish (such as oysters and mussels) has been gathered in the new document.

 

Some of the highlighted information in the document concerns the major viruses that can be found in sewage-contaminated shellfish. These viruses can cause hepatitis and gastroenteritis and are the major risks associated with consumption of bivalves in Europe.

 

Current approved treatment and control measures diminish, but do not totally eliminate risks associated with sewage contaminated bivalve shellfish.

 

Another issue that is highlighted in this document is the significant technological changes in the ability to detect the level of virus contamination in shellfish. Research has been conducted within the SEAFOODplus project REFHEPA, in order to standardize Real-Time PCR methods for detecting pathogenic viruses in shellfish. This system is providing a significant contribution in this area of food safety.

 

Detection and quantitation of pathogenic human viruses using Real-Time PCR procedures

The results of this research are part of a wider effort to introduce validated methods for routine use in laboratories in Europe, through the European Committee for Standardization (CEN) process.

 

The new methods have already been used within the SEAFOODplus project REDRISK for giving a greater understanding of the conditions leading to viral contamination of shellfish. Understanding how and when the contamination occurs is the first step in developing improved risk management procedures in shellfisheries. Results indicate that environmental conditions, such as heavy rainfall, can have a highly significant role in the viral contamination. It is shown that such events can cause an overflow of sewage, which may bypass treatment. These events then become highly significant, as they can create a route for virus transmission during epidemic periods of illness in the community.

  

New tools for detecting viruses are developed and a growing understanding of virus contamination of shellfish is gained from the SEAFOODplus projects. It is an appropriate time for stakeholders to come together and determinate strategies for reducing the virus risk associated with shellfish consumption.

 

For this purpose, SEAFOODplus organised a workshop dedicated to this subject on the 4th of June 2007, in Bilbao, prior to the SEAFOODplus Annual Conference. All stakeholders, including regulators, the industry and scientists attended and gave their input. Details on the programme and the resulting recommendations are given in the Events section of the SEAFOODplus homepage.