Occurrence of Vibrio parahaemolyticus in Dutch mussels

A study was carried out on the occurrence of Vibrio parahaemolyticus in Dutch mussels originating from the East Schelde Estuary. In a totol of 79 10-g tissue samples, 3 (3.8%) were found to contain V. parahaemolyticus. In a second survey, 6 out of 23 bags of mussels (26%) contained one or more strains of V. parahaemolyticus in 5-g tissue samples. The many limitations of current methodology used in such surveys are stressed. Positive samples can be missed because viable cells may die during refrigerated transport. Surviving cells also may not be detected because they have been sublethally stressed. In addition, the unreliability of the identification criterion of no growth in 10% NaCl was demonstrated.