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Cooked rice and Bacillus cereus

Also called fried rice syndrome

Why leftover rice needs handling more carefully than most cooked food.

What it is

Cool cooked rice quickly โ€” ideally within an hour โ€” keep it refrigerated, use it within a day, and reheat it once until steaming hot all through. Do not hold it warm for hours and do not leave it out overnight.

Why it works

Bacillus cereus survives cooking as spores. Cooked rice left in the danger zone lets those spores germinate and produce a heat-stable toxin, and reheating destroys the bacteria while leaving the toxin intact. The illness is from the toxin, not the organism, which is why "I reheated it thoroughly" is not a defence.

When to use it

Every dish that keeps cooked rice, pasta or other cooked starch for later, including fried rice made from yesterday's.

What goes wrong

Leaving a pot of rice out to cool slowly; keeping a rice cooker on warm all day; reheating the same rice twice; judging it by smell, which tells you nothing about the toxin.

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