Purpose: The purpose of the study was to determine whether or not raw, live oysters sold in Toronto posed a bacteriological hazard to consumers.
Methods: Seven hundred and fifty oysters were collected from randomly selected retail locations across the city of Toronto. The oysters sampled came from various locations. Samples were examined for aerobic colony count, Vibrio species and Escherichia coli. The method for Vibrio species was based upon a standard method published by the UK Health Protection Agency. The E. coli method was based upon the International Organization for Standardization method. Aerobic colony count was carried out using a method that used plate count agar and incubation at 37°C. Biochemical tests were used to confirm identification.
Results: The results showed that none of the oysters were contaminated with E. coli, and the aerobic colony counts were all within acceptable limits. V. alginolyticus was isolated in 20% of the samples. Furthermore, Pasteurella pneumotropica and Pasteurella multocida were each isolated in 8% of samples.
Significance: It was concluded that the live oysters sold at retail in Toronto, Canada, were of relatively good microbiological quality and that none of the isolated bacterial species posed a major gastrointestinal threat to consumers, indicating that raw, live oyster consumption in Toronto is relatively safe from a bacteriological perspective.