Ask the experts: Leftover rice

Q: "Can I get sick from leftover rice?"

A: Yes! Uncooked rice often contains the bacteria Bacillus cereus which can form spores that survive cooking. If rice is cooled slowly, these spores can produce a toxin, but the rice will not look or taste any different. Reheating rice before serving does not inactivate the toxin nor kill all the bacterial cells, so the rice may not be safe. If you eat cooked rice contaminated with Bacillus cereus toxin, you’re likely to suffer nausea and vomiting, and possibly diarrhoea within 10-12 hours. The only good news is you’re likely to recover within 12-24 hours.

It’s best not to cook too much rice in advance. If you do have leftover rice, however, NZFSA advises us to cool it in a colander under cold running water, or place it in the fridge straight away and use within two days.