Bacillus cereusis a spore-forming bacterium that can be frequently isolated from soil and some food and which produces toxins. These toxins can cause two types of illness: one type characterized by diarrhea (long incubation, 8-16 hours) and the other by nausea and vomiting (short incubation, 1-6 hours).
The short-incubation form is most often associated with rice dishes that have been cooked and then held at warm temperatures for several hours.
Long-incubationB. cereusfood poisoning is frequently associated with meat or vegetable-containing foods, after cooking. The bacterium has been isolated from dried beans and cereals, and from dried foods such as spices, seasoning mixes and potatoes.
The short-incubation or emetic form of the disease is diagnosed by the isolation ofB. cereusfrom the incriminated food. The long-incubation or diarrheal form is diagnosed by isolation of the organism from stool and food.