Factors Affecting E. Coli Levels in Shellfish with Reference to EEC Directive 91/492

Summary

The contamination of bivalve molluscs by viral pathogens is of concern to Public Health Authorities and the shellfish industry because of the potential health risks and loss of markets for bivalve molluscs. As part of the Single European Market (SEM) the European Commission has introduced a Directive (91/492/EEC) which requires shellfish harvesting waters to be classified according to their levels of bacterial contamination; faecal coliforms or Escherichia coli as assessed by a 5 tube 3 dilution Most Probable Numbers test found in the shellfish collected from those waters. The intention is that bivalve molluscs which originate from areas of bacterial contamination shall undergo depuration or, if contamination is found to be severe, prolonged relaying, in order to ensure viral safety. Before the EEC Directive can be implemented it is necessary to design sampling protocols which would result in consistent classification of shellfish growing waters. This project is intended to examine the variables which could affect E. Coli levels in shellfish surveys and to design means by which bias resulting from these variables could be overcome. This report has been produced from a scanned original and may therefore contain some formatting and other inaccuracies. In cases where this affects the technical content, a paper copy of the original report can still be obtained from Seafish.

Author

• W. Lart

Publication Reference No.

SR419

Publication date

01 June 1993