Turns out not all foods are made to be reheated. In fact, doing so can can actually cause you to be very, very sick.
These are the six foods experts recommend you think carefully about before packing them into your lunch bag.
Oh, leftover Chinese takeaway, how we will miss you so.
The problem here? The variation in temperature encourages bacteria growth.
“Uncooked rice can contain spores of bacteria that can cause food poisoning. When the rice is cooked, the spores can survive… Then, if the rice is left standing at room temperature, the spores will multiply and may produce poisons that cause vomiting or diarrhoea. Reheating the rice won’t get rid of these poisons,” advises Food Standards Australia (FSA).
If you must, the FSA recommends reheating all food rapidly to at least 70 degrees and holding it at that temperature or hotter for at least two minutes to minimise the risk.
It’s common knowledge that poultry, in particular chicken, carries a high risk of salmonella if not prepared or cooked properly.
When reheating in the microwave, not all sections of the food are penetrated equally meaning varying temperatures can encourage bacteria growth.
Watch: Dani Venn shares her delicious hoisin pork rib recipe – too good to have leftovers! Post continues after video
As a protein-dense food, the proteins also break down differently when reheated which can upset the stomach.
We'll be rethinking our chicken lunches. Image: iStock
It's a similar story for mushrooms, sadly. The proteins deteriorate as soon as they're cut up and reheating 'em will exacerbate this and potentially cause some painful stomach issues.
According to the European Food Council, there's a way round it if you can't bear to think of missing out on that leftover mushroom risotto.
"If they are stored in a fridge and for not more 24 hours, it is in general no problem to reheat mushrooms again at recommended temperatures of 70 C," their guide states. Thanks guys, we'll take it. (Post continues after gallery.)
Popeye may have eaten it everyday for breakfast, lunch and dinner, but unless it's fresh you shouldn't be.
Along with other leafy veggies, spinach can often contain high concentrations of nitrates. When heated multiple times, these nitrates become toxic and release carcinogenic properties. The European Food Information Council advises avoiding reheating this food entirely.
Eggs can contain traces of salmonella, which when consumed can seriously harm or even kill. The US Food and Drug Administration estimates that salmonella poison is responsible for 79,000 cases of food poisioning and 30 deaths - so it's not to be taken lightly.
Whether they're boiled, scrambled or fried, if you can, avoid reheating. If you must, ensure cooked eggs or egg dishes are immediately refrigerated after serving and heated to over 70 degrees Celsius before being served a second time.
The issue with potatoes is largely to do with how they are stored after they are cooked.
Leaving them at room temperature and out of the fridge may encourage conditions in which the bacteria Clostridium Botulinum thrives. The situation is worsened if they're kept in foil, which prevents any oxygen from getting in.
The temperature we reheat potatoes at is not always enough to ensure the bacteria is killed off, so it's really important to take care how you store them when they're cooling. Not sure? Don't reheat and eat.
Any foods you didn't realise you weren't meant to reheat?