MODEL RELEASED. Bacillus cereus food poisoning. Microbiologist holding a petri dish containing a culture of B. cereus bacteria in one hand and a sample of reheated rice in the other. B. cereus is a Gram positive, spore forming bacteria found in soil, water and on food. It produces an indigestible toxin that causes foodborne illness. It is particularly prevalent on rice that has been cooked and then improperly refrigerated. When the rice is reheated, the bacterial spores survive and germinate, leading to nausea and vomiting after consumption.