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 glucose at > 50 milligrams, did not support diarrhoeagenic toxin production by psychrotrophic Bacillus cereus despite growth to high counts (approximately 10(7)/ml) over a 4 d period of incubation at 21 degrees C. In contrast, starch levels of 10 and 50 milligrams actually enhanced toxin production. Toxin production was also affected by pH levels of broth cultures, and was concomitant with alterations in bacterial growth. These findings help to explain variations in toxin levels previously found in some dairy desserts, which were thought to be associated with pH and sugar content (Sutherland, 1993).