10 Foods That Should Not Be Reheated

Almost every day we make too much food, and later that night or even days later, we reheat and eat these leftovers. We all know what reheating food is and many times we could hear warnings that it is not safe to reheat certain foods. While there is some truth in that, many foods can be reheated, as long as it is done properly. But some foods can become even poisonous after reheating. So these are the foods that shouldn’t be reheated:

1. Rice

Have you ever heard that eating reheated rice can result in food poisoning? It is, in fact, the way it is stored before being reheated that could mean it carries bacteria.

The problem comes when cooked rice is kept at an unsafe temperature for a longer time as this environment allows the spores to breed.


No amount of reheating after that can kill them. A bacillus cereus bacterium in rice causes this food poisoning. If cooked rice is left at room temperature, bacteria can multiply and may create toxins that cause diarrhea or vomiting. So eating reheated rice is not a problem as long as it has been stored in the right way, not standing at room temperature for more than 2 hours, prior to the reheating.

2. Mushrooms

Leftovers, like mushrooms, must be refrigerated no more than two hours after cooking and eaten the same day without reheating.

Of the ten foods on this list, mushrooms present the biggest health risk. Mushrooms are often added to many cooked meals, but they should be consumed right after cooking or cold the same evening.

This is true for risottos, as well as soups, which are made with mushrooms. When we reheat the mushrooms there is a change in the composition of protein that changes the taste of food. This may cause a variety of digestive problems, and the mushrooms may lose all their valuable nutrients and all health benefits are gone. Once heated, they change their physical composition, so if the mushrooms are a part of your meal, try removing them before reheating.

3. Celery

Although most people store celery in their fridge and consume it fresh, many times the celery is used in casseroles or soups. So just like spinach, when the celery is once heated, it releases nitrates when we cool it and then reheat again.

However, when you are reheating the soup, make sure you take out celery since the nitrate contents of celery can make you big health problems if it goes under reheating for the second time.

Generally speaking, any healthy and good nutritional vegetable that comes around the Celery family or carrot family, can turn into toxic food if reheated on a continuous basis. If you put celery in a soup or casserole dish, consume your meal instantly and throw the leftovers in the trash can.

4. Eggs

If you cook eggs for breakfast, no matter if they are fried or scrambled, and then leave them for later, you should know that you must eat them cold.

Eggs, like chicken, can make toxic substances after they were cooked, cooled, and then reheated again, especially when you choose the highest temperatures when reheating.

It is not the rule for the foods where the eggs are part of sauces like béchamel, but the rule refers to meals with boiled or fried eggs. It might sound silly, especially if you have reheated the eggs and eaten them before with no consequences. If it was so, you just might have been lucky, but if you don’t want to experience a really bad food poisoning, we give you an advice to quit while you are ahead and avoid reheating these dangerous foods.

5. Chicken

There is a good reason why most people soon after eating, store their chicken in the refrigerator and then eat it cold the same day.

Once it is cooked and then cooled and reheated, the high level of protein in chicken changes. Like rice and mushrooms, consuming reheated chicken, especially if it is reheated to a highest temperature, can cause food poisoning.

After you reheat it once, you should not reheat it a second time again. Chicken can be safely reheated, just do not use the microwave, but put it in the oven or a toaster oven to heat it slowly but thoroughly. It does take more time than just simply put it in the microwave for a few minutes, but reheating it slowly will keep you healthy and safe.

6. Spinach

Spinach is a super healthy food that many people enjoy in their salads, but there are many people who eat spinach as a side dish. But did you know that spinach is one of the worst foods that should never be reheated?

Spinach together with other leafy vegetables contains the high amount of nitrate that depends on the variety, season, soil and water conditions where the spinach has grown.

Nitrate itself is really safe and harmless, but as it converts to nitrites, and then again to nitrosamines, we get the foods that can be carcinogenic. This mostly occurs after spinach is heated, stored and then again reheated. It affects the ability of the blood to transport oxygen by transforming hemoglobin, into methemoglobin, a protein that is not able to carry oxygen. So eat it cold or throw out the leftovers.

7. Potato

It is not good to leave baked potatoes out at room temperature overnight and reheat them and eat them the next day. This is a food safety issue.

Potato, when baked, has a neutral PH factor and can quite easily grow microorganisms. This vegetable is a highly nutritional food which we should not reheat because it so loses most of its nutrients, and even becomes toxic.

Consume it tight after preparation or even better cold. Besides the possibility of becoming toxic after reheating, they will lose up to 30 % of their remaining folate and vitamin C. To minimize nutrient loss and to prevent the possible poisoning, the best way is to consume the potatoes is without reheating. If you are preparing stews for a few days, use the potatoes and add them subsequently.

8. Beet

Like spinach, beets also contain nitrates, which are very useful for your health, but these nitrates become extremely harmful with reheating.

Because after reheating the chemical composition in beet changes, resulting in foods that is non-edible and dangerous. When the beet is reheated it can become very dangerous for your body, as the whole amount of it can become completely nitrate.

When heating is performed, under the action of microorganisms, it transforms nitrate molecules into nitrosamines. They are carcinogenic to the human body. Beet is among is the most harmful vegetables after reheating so it is recommended to be consumed best when fresh. This doesn’t mean that you should not eat this food like other food, but only you should avoid reheating.

9. Turnips

The number of nitrates in turnips can be very harmful to our body if reheated.

Turnip is potentially hazardous food that after we cook it shouldn’t be cooled and reheated again the second time, to avoid the food being at temperatures that support the growth of pathogenic bacteria. If pathogens were present in the food, they could multiply to dangerous levels.

You should always be concerned about bacterial growth, however, especially when you put away your cooked turnips on a room temperature for two hours or longer before refrigerating it. The two-hour mark is generally considered the point at which bacteria will begin to grow. Because turnips as already sad contain a high amount of nitrates, just make sure that it is not left out for a long time and don’t reheat it. The best is to consume this vegetable fresh and well washed.

10. Oils

Although many fast food restaurants freely reheat cooking oil on a regular basis, it is not really a healthy habit.

Many studies have shown that reusing cooking oil can expose you to many dangerous toxins, which could lead to serious health issues. In particular, it has been shown that reheating oils like corn, canola, soybean, and sunflower oil release a toxin (4-hydroxy-trans-2-nonenal or HNE).

This toxin has been linked to increased risk of many health problems, including-Alzheimer’s disease, Parkinson’s disease, liver disorders, cardiovascular problems, and cancers. Knowing these risks before and avoiding reheating cooking oil can change your mind about these unhealthy eating habits. Particularly present in restaurants, reheated oil can be harmful if consumed in a long term, and should be avoided in most cases.