10 Foods that should never be reheated in the microwave

Toxic Warning: 10 Foods that should never be reheated

Angela Goh

24 May 2017

1/10
Eggs
With the shell still on, as a scramble or omelette, mixed through a dish… the proteins in eggs are naturally difficult to digest (especially because of the whites), so eggs should never be reheated! Subjected to high temperatures, the proteins get destroyed, rendering the egg inedible. This could interfere with your digestion.
2/10
Chicken
If you were planning on warming up your leftover piece of chicken breast from last night, forget the idea! Chicken contains a lot of protein, which can be altered when subjected to heat. This could cause serious digestion issues. To avoid this inconvenience, try eating it cold in a salad or sandwich, or with a little mayonnaise.
3/10
Mushrooms
Like chicken and eggs, mushrooms shouldn’t ideally be eaten on the same day that they are cooked because of the complex protein content they have that could be destroyed and rendered inedible. In addition, the great source of vitamins and minerals in the mushrooms will also be likely to be lost from the heat.
4/10
Oils
There are already several oils out there - such as avocado, flax, walnut, and grape seed oils - that should never be heated in a pan or microwave (lest they go rancid). The same applies for most other oils. When cooked a second time, the oils will release substances that are toxic to the body. It’s best to cook your food with as little fat as possible, and choose sunflower oil, which is less likely to become rancid through heat.
5/10
Seafood
Shrimp, prawns, mussels, shellfish… unsurprisingly, seafood is on this list. Seafood should taste as fresh as possible, and should never be cooked again! Or you might risk a rubbery, indigestible mess.
6/10
Rice
This might come as a surprise. Rice, when you cook it the first time and leave it to cool (before storing it), is very susceptible to growing bacteria at a very rapid rate. When you finally place your leftovers in the fridge after dinner, you leave the bacteria to fester overnight. By the time you reheat your rice the next day, you might be ingesting plenty of unwanted bacteria.
7/10
Turnips
Delicious when cooked with carrots and other root vegetables, turnips are gorged with water and are excellent for your health. However, because of its high water content, it is better to avoid reheating them a second time as you will run the risk of exposing yourself to food poisoning.
8/10
Beetroot
Beets, spinach, lettuce, celery, and any other vegetable that contains nitrates shouldn’t be reheated! Why? Because when they are recooked, the harmless nitrates contained in these vegetables turn into nitrites, which are recognised to be potential carcinogens.
9/10
Potatoes
Like rice, if you leave this starchy ingredient to sit at room temperature to cool down before you store the leftovers, you are giving bacteria the time to grow and fester. This bacteria can be very hard to kill off, even with a second reheating.
10/10
Coffee
If you’re the type of person to forget all about your coffee and leave it until it becomes cold, just know one thing: don’t reheat it. When you make fresh coffee and leave it to cool, its chemical makeup changes and its acidity increases. By reheating it a second time, you will further ruin the flavour profile of the coffee and break down all the aromatics, contributing to a bad taste.

Not all foods are made to be reheated. Some of them even become toxic and therefore dangerous to health when cooked a second time. Here are 10.

Food wastage, budgeting, time saving… for various reasons, many of us have become accustomed to freezing or refrigerating our leftovers to tie us over for the next few days. While certainly an economic choice, keeping leftovers for tomorrow night’s dinner might actually come with a health risk if you’re not careful!

Depending on your reheating methods, some foods such as chicken, mushrooms or rice can become toxic when cooked a second time. Subjected to high temperatures, their chemical makeup will undergo changes that make them more likely to cause a stomach upset, digestion problems, food poisoning, or worse: expose the consumer to carcinogenic substances.

Head up to the gallery for a list of foods that you shouldn’t reheat a second time.

Angela Goh & Marie France Editorial Team

Photos: Getty Images

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