Bacillus cereus is a Gram-positive, rod-shaped bacterium that can produce endospores. It is facultatively anaerobic but can grow under aerobic conditions. Its optimum growth temperature is 20–40 °C (some strains can even grow at 4 °C). Its spores are resistant to heat, disinfectants, drying and radiation. Bacillus cereus is found in soil, water, air and food products. It grows very well in products containing starch: it is often found in tinned food, ready-to-eat food, seasoning (cinnamon or ground paprika), meat and milk. The bacteria cause illness in animals and humans. In animals, they cause purulent infections and pericarditis. In humans, they cause food poisoning with diarrhoea or vomiting. Most frequently, vomiting occurs after consuming cooked rice or another high starch product kept for a long time at the room temperature. Diarrhoea occurs after eating meat or ready-to-eat meals improperly stored. The incubation period in the body is from 0.5 to 15 hours; usually, symptoms subside within 24 hours.