One often hears that it鈥檚 not safe to eat reheated rice. Why is this? Surely anything that is living in the uncooked rice is killed by boiling it. If you then freeze the rice very quickly, it must be pretty much sterile and can be reheated when required. I鈥檝e done this for years and am unaware of any ill effects. Am I dicing with danger?
鈥� Bacillus cereus is the most common cause of poisoning from reheated rice. It is found in soil, and the heat-resistant spores can survive boiling, allowing them to germinate when the rice cools.
Fortunately it seldom invades your organs, but infected rice toxins produced by the bacteria may cause nausea and a painful case of diarrhoea within hours of eating.
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Healthy people generally recover in a day or two with no more treatment than staying close to a lavatory and drinking plenty of rehydrating fluids, but it may be difficult to tell an acute attack from more dangerous types of food poisoning. Some strains of Bacillus cereus may also themselves be dangerous, so don鈥檛 complacently refuse to see a doctor if necessary.
鈥淚t may be difficult to tell an acute attack from more dangerous types of food poisoning鈥�
These effects are largely avoidable. To forestall any problems, cook your rice until it鈥檚 hot and eat it soon. If you want to keep any, prevent the bacteria from multiplying by either keeping the rice too hot to touch (60 掳C or higher), or cooling it to fridge temperature (about 4 掳C or lower) as fast as possible, even if that means putting it warm into your fridge or freezer. Such modest heat and fast cooling won鈥檛 kill spores, but will prevent them from germinating and producing toxins.
Jon Richfield, Somerset West, South Africa
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