Toxin production by Bacillus cereus in dairy products.

Spores of a known toxigenic and psychrotrophic dairy isolate of Bacillus cereus (HRM 44) were unable to grow and produce diarrhoeagenic toxin at 6 degrees C in creams and dairy-based products. These findings suggest that the production of B. cereus diarrhoeagenic toxin is unlikely to occur in creams and dairy-based products maintained within the cold chain. Growth and toxin production were readily demonstrated in creams and some desserts stored at 21 degrees C. Growth in creams was associated with obvious spoilage. However, in the flavoured desserts, spoilage was not always obvious before significant growth of B. cereus and toxin production had occurred. Dairy desserts with high sugar content and/or low pH did not support toxin production and these findings are discussed.