Bacillus cereus is an endemic, soil-dwelling, Gram-positive, rod-shaped, beta hemolytic bacterium. Some strains are harmful to humans and cause foodborne illness, while other strains can be beneficial as probiotics for animals.

B. cereus competes with other microorganisms such as Salmonella and Campylobacter in the gut, so its presence reduces the numbers of those microorganisms.  In food animals such as chickens, rabbits and pigs, some harmless strains of B. cereus are used as a probiotic feed additive to reduce Salmonella in the intestines and cecum. This improves the animals' growth as well as food safety for humans who eat their meat.

Heating can activate spores, which allows them to germinate and grow under favorable conditions. Time and temperature abuse of cooked food permits the activated spores to grow and produce toxins. Control relies on prompt refrigeration and cooling of foods quickly to less than 41°F (5°C) to minimize growth and toxin formation.