Hungry after a long day, you reach for that takeout container of fried rice from where it’s been sitting on your counter for the last four days. But a few hours later, you’re in trouble—at least, your stomach is. The culprit behind your food poisoning is a bacterium called Bacillus cereus  (or B. cereus ) , which was hidden in the grains of rice you’d eagerly consumed. Rice left out at room temperature, like the container you just ate, can become unsafe to eat due to bacteria