Every year, there are around 1.7 million cases of food poisoning recorded in the UK, and a whopping 15 per cent of these result from people eating reheated rice. This is thanks to a bacteria called Bacillus cereus, found in the soil and dust of almost all rice-growing regions around the world. No amount of washing will remove it, and it can even tolerate boiling water.
In dry conditions, the bacteria stay in their spores but, as soon as their surroundings are warm and wet, they begin to grow and breed. Most of the time, this is not a problem, since the rice is consumed so soon after being cooked that they haven’t had time to reproduce. But leave the rice at room temperature overnight and you give them every chance to multiply.
The good news is that rice can be reheated and eaten — but only if it’s been stored and cooked in the correct way. The key, say chefs, is storage and temperature control.
All rice should be kept bone-dry, cooked thoroughly to a temperature of at least 75c and then served immediately. If it is not to be served straight away, it should be kept at 63c or above, or cooled to at least 15c as quickly as possible.
The best way to do this is by placing the rice in a colander or sieve and running it under cold water for a couple of minutes. It will then be ready to put straight into the fridge, and this should be done within an hour of cooking.
Reducing the temperature in this way means the bacteria don’t have time to multiply and produce toxins. Nevertheless, it is strongly recommended that properly-stored leftover rice is consumed within one or two days.
Lastly, never reheat rice from a takeaway, as many restaurants make their rice in bulk and then reheat it as and when they need it — and rice should never be reheated twice.
Best of all, cook the correct amount of rice in the first place. Not that that’s likely to happen any time soon.