Effect of temperatures on the enterotoxin production of Bacillus cereus in cereal grains

초록

Effect of various temperatures on enterotoxin production of Bacillus cereus 4 different cereal grains (brown rice, glutinous rice, barley, and Job's tear) was studied. When B. cereus was inoculated to 4 grains, no toxin was detected within 24 hr at 20 and 25 degrees C although the population reached approximately 8-10 log CFU/g. However, enterotoxin was detected in all samples above 30 degrees C. When the temperature was increased to 35 degrees C, toxin production was observed in the range of 6.11 and 6.26 log CFU/g on brown rice and glutinous rice, respectively. At 40 degrees C, toxin production was detected after 6 hr with the lowest bacterial population of 5.32 and 5.04 log CFU/g, whereas enterotoxin was produced in the range of 6.86 and 7.77 log CFU/g oil barley and Job's tear at 40 degrees C. Different types of food affected enterotoxin production of B. cereus. These results suggest that enterotoxin production was more significantly regulated in incubation temperatures than the number of B. cereus.

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