Food Poisoning and Rice, do you know who to balme?


Saturday night’s take away can often look appealing on a Sunday morning, especially if you’ve had a late night! For those of you that can’t resist reheating this tempting cuisine it can often lead to severe stomach cramps, sickness and diarrhoea. We are quick to blame last night’s ale or the meat from our favourite Takeaway. Well, here’s the surprise, your bout of food poising is probably from your rice!  

The food poisoning bacteria Bacillu cereus is naturally found in cereals such as rice.  Washing rice will not help avoid the potential problem and surprisingly neither does cooking! 

How is food poisoning caused? 

Bacillus cereus bacteria are heat resistant. They survive cooking by forming protective spores. This is basically like a heat resistant jacket that the bacteria like to wear in unfavourable conditions. When the temperature conditions are again favourable (for example rice is left on your kitchen work surface for a prolonged period of time), the spores germinate, or take off their protective jackets, and Bacillus bacteria are released into the food, now able to grow and multiply.

As the Bacillus bacteria multiply in your rice, they produce a waste product which is poisonous to us (called an exotoxin). This toxin is heat stable, and therefore, even if the rice is thoroughly reheated before consumption, it will still be present in the food.  The poison affects the upper gastrointestinal tract and the consequences of eating food containing the toxin are that we shall experience abdominal cramps and vomiting within 1 to 5 hours after eating, with the symptoms lasting 6 to 24 hours.

This is not the only danger with rice – it can have a ‘double whammy’ effect.  If the Bacillus bacteria are eaten whole i.e. the food is not piping hot before consumption, the bacteria are broken down in our intestines where they release another type of poison (called an endo toxin).   The effects of this toxin take around 8-12 hours after eating to take effect, and the symptoms are mainly stomach pain and diarrhoea.  Symptoms last 1-2 days.

So, in short, eat your rice as soon as it’s cooked. Never reheat rice and don’t leave your take away out at room temperature!

For further information and advice on Food safety why not come along to one of our courses?