Bacillus cereus is a Gram- & catalase-positivepositive, spore-forming facultative anaerobic rod-shaped bacteria.

It can cause food poisoning, and is particularly noted for doing so in rice. During high-temperature cooking, bacilli that have contaminated the uncooked rice reproduce, then form protective spores when the rice cools. On rewarming, the spores germinate and, when the rice is eaten, can cause severe diarrhea, vomiting, and abdominal cramps.

This can be prevented by proper food handling techniques.