To determine the roles of Bacillus cereus as a food contaminant and potential pathogen in pasteurized milk, the putrefactive and toxigenic activities of B. cereus in milk were studied at both 25 and 30°C. Vegetative cells of B. cereus rapidly increased to 10⁷-10⁸ CFU/ml and putrefied the milk. We found that B. cereus B-4ac produced a diarrheal enterotoxin during growth in milk and B. cereus NC 7401 produced a vacuolation factor. More than 2 × 10⁷/ml of bacterial cells were required to detect the two toxins produced in the milk. However, no detectable toxin was produced by either strain during incubation in milk at 10deg;C.