Behavior and incidence of Vibrio parahaemolyticus in Sydney rock oysters (Crassostrea commercialis)

Vibrio parahaemolyticus grew poorly or not at all during storage of unopened Sydney rock oysters (Crassostrea commercialis ) at 15 and 30 degree C for 2 and 7 days. Although V. parahaemolyticus counts often increased at 30 degree C, counts above 10 super(4)/g were not observed. Escherichia coli) counts did not usually change substantially under these conditions. A survey of 30 market samples of oysters was conducted. Sixteen samples of unopened oysters were collected at the wholesale level and 14 samples of refrigerated opened oysters were purchased from retailers. V. parahaemolyticus was present in all samples of unopened oysters (range 0.4/g-2.3 x 10 super(4)/g) and in 13 samples of opened oysters (range 4.3/g- > 1.1. x 10 super(3)/g).