Publication Abstract

Levels of F-specific RNA bacteriophage and Escherichia coli in Molluscan Bivalve Shellfish

W. Dore, M. Mackie and D Lees

Methods and Results: A total of 608 shellfish samples from 49 shellfish harvesting areas were analysed for E. coli and FRNA bacteriophage using standard published methods. The geometric mean concentration of FRNA bacteriophage in all samples was over three times greater than that of E. coli (1800 and 538 counts 100g^-1 for FRNA bacteriophage and E. coli respectively). In contrast to E. coli, FRNA bacteriophage concentrations were strongly influenced by season with a geometric mean count of 4503 pfu 100g^-1 in the winter (October to March) compared with 910 pfu 100g^-1 in the Summer (April to September).

A total of 608 shellfish samples from 49 shellfish harvesting areas were analysed for and FRNA bacteriophage using standard published methods. The geometric mean concentration of FRNA bacteriophage in all samples was over three times greater than that of (1800 and 538 counts 100g for FRNA bacteriophage and respectively). In contrast to , FRNA bacteriophage concentrations were strongly influenced by season with a geometric mean count of 4503 pfu 100g in the winter (October to March) compared with 910 pfu 100g in the Summer (April to September).

Conclusions: FRNA bacteriophage were present in shellfish at higher concentrations than E. coli. Elevated levels of FRNA bacteriophage observed in the winter concur with the known increased viral risk associated with shellfish harvested at that time of year in the UK. Levels of FRNA bacteriophage found in many shellfish from category B harvesting areas would not be eliminated by conventional treatment processes.

FRNA bacteriophagewere present in shellfish at higher concentrations than . Elevated levels of FRNA bacteriophage observed in the winter concur with the known increased viral risk associated with shellfish harvested at that time of year in the UK. Levels of FRNA bacteriophage found in many shellfish from category B harvesting areas would not be eliminated by conventional treatment processes.

Significance and Impact of the Study: Data from this study will inform future proposals to introduce FRNA bacteriophage as an indicator of the viral risk associated with shellfish.

Data from this study will inform future proposals to introduce FRNA bacteriophage as an indicator of the viral risk associated with shellfish.

Aims: Current measures for controlling the public health risks associated with bivalve molluscan shellfish consumption rely on the use of E. coli to indicate the sanitary quality of shellfish harvesting areas. However, it has been demonstrated that E. coli is an inadequate indicator of the viral risk associated with shellfish. An alternative indicator organism, male-specific RNA (FRNA) bacteriophage has been proposed for this role. This study compared the distribution of E. coli and FRNA bacteriophage in shellfish harvesting areas.

Reference:

W. Dore*, M. Mackie* and D Lees* (2003) Levels of F-specific RNA bacteriophage and Escherichia coli in Molluscan Bivalve Shellfish. Letters in Applied Microbiology 36 (2) 92-96