Reheating a takeaway (or if you’re American, take-out) may seem like a good idea at the end of a hard day – but many of us have learnt that there can be a heavy price to pay. Around one million people in the UK suffer food poisoning each year, and it’s often because we have failed to take a few simple steps.

In the video below, Michael Mosley of the TV programme Trust Me I’m a Doctor uses a thermal camera to analyse whether reheated takeaway food is safe or not:

As Mosley explains, the trick is to heat the food until it is 82C (176F) throughout to be sure that you can kill any harmful bacteria.

That’s easier said than done: while the outside may seem to be steaming, the inside could have remained cooler – hosting a pocket of living bacteria. It’s for this reason that it’s important to stir the dish so that all the food is heated evenly.

One particular takeaway favourite can host spores of a nasty bug called Bacillus cereus

Even after having followed these steps, you shouldn’t reheat a meal more than once. Each time it cools down, you offer more opportunities for the harmful bacteria to multiply, making it harder to kill them all off the next time you stick them in the oven or microwave.

This is particularly true for one particular takeaway favourite – rice – which can host spores of a nasty bug called Bacillus cereus. When left in food, the bacteria produces toxins that trigger diarrhoea and vomiting. Unfortunately, these toxins are “heat stable” meaning that even if you heat the rice to the point of killing all the bacteria, the toxins will survive – and you’ll soon notice the effects of ingesting those poisons.

If you do want to save your leftovers, you should cool the rice quickly – before the bacteria can start churning out those toxins – and refrigerate within an hour of cooking. Otherwise you really are “playing Russian roulette with your guts”, says Mosley.

Watch another Trust Me I’m A Doctor video: How much coffee should you drink?

The video above is an original short co-commissioned with Britlab. For more great Britlab stories, visit their YouTube channel.

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