INFLUENCE OF PH AND SUGARS ON THE GROWTH AND PRODUCTION OF DIARRHOEAGENIC TOXIN BY BACILLUS-CEREUS

Broth cultures supplemented with high levels of sugars, particularly g lucose at > 50 g/l, did not support diarrhoeagenic toxin production by psychrotrophic Bacillus cereus despite growth to high counts (approxi mately 10(7)/ml) over a 4 d period of incubation at 21-degrees-C. In c ontrast, starch levels of 10 and 50 g/l actually enhanced toxin produc tion. Toxin production was also affected by pH levels of broth culture s, and was concomitant with alterations in bacterial growth. These fin dings help to explain variations in toxin levels previously found in s ome dairy desserts, which were thought to be associated with pH and su gar content (Sutherland, 1993).