Bacillus cereus can form hardy spores and produce toxins. FoodSafety.gov links it to rice, leftovers, sauces, and soups left out too long at room temperature.
Two illness patterns are described: one with watery diarrhea and cramps (6–15 hours), another with nausea and vomiting (30 minutes to 6 hours). Illness usually lasts about 24 hours.
Refrigerate cooked food promptly in shallow containers. Keep hot foods above 140°F and cold foods at 40°F or below.