Food poisoning potential of Bacillus cereus strains from Norwegian dairies.

Characteristics concerning diarrhoeal potential were investigated in B. cereus dairy strains. The thirty-nine strains, isolated from whipping cream, were tested for cytotoxicity after culturing at human body temperature as well as 25 degrees C and 32 degrees C. At 37 degrees C, none of the strains were highly cytotoxic. This observation suggests that those strains should be considered to pose a minor risk with regard to diarrhoeal food poisoning. However, some strains were moderately or highly cytotoxic when grown at 25 degrees C and 32 degrees C. While the majority of the strains were able to grow at refrigeration temperatures, only four B. weihenstephanensis strains were identified among them when subjected to discriminative PCR assays and growth temperatures which delimit this species.