Incidence of Salmonellae in Clams, Oysters, Crabs and Mullet1

Abstract

Sixty samples each of oysters (Crassostrea virginica), clams (Mercenaria mercenaria), striped mullet (Mugil cephalus), and blue crab (Callinectes sapidus) were analyzed for the presence of salmonellae within 4 h of harvesting from an east and west coast location in Florida. Mullet was the only seafood from which salmonellae were not recovered. Clams from the west coast location had the highest incidence (43%) of salmonellae. Eleven serotypes of Salmonella were recovered and identified from the samples. In quantitative MPN studies, the number of salmonellae present in west coast oysters was 2.2 organisms per 100 g of oyster meats. The variety of serotypes isolated, coupled with consistent recoveries throughout the year, suggests that salmonellae may represent a portion of the natural background flora in these seafoods rather than recent single source contamination.