Does reheating food kill bacteria?

In this article, we answer the following question: Does reheating food kill bacteria? We talk about how bacteria reproduce and how to correctly cook and handle food to eliminate any health risk.

Does reheating food kill bacteria?

In most cases, yes, reheating food will kill bacteria. Heat is a major source of pathogen destruction. The sanitizing function of cooking is due to the fact that there are many pathogenic microorganisms that cannot withstand temperatures above 55ºC. 

At these degrees, which are reached in most cooking methods, bacterial accumulations begin to degrade and do so more as the temperature is maintained over time or if it increases. Despite the effectiveness of the cooking, this does not exempt the fact that appropriate handling and hygiene guidelines have been followed before, that is, that the food must be washed well to remove either traces of dirt or other substances that may be present ( except chicken, which is advisable not to wash).

However, to more safely mitigate the effects of a virus, it must be in an environment whose temperature approaches the boiling point, that is, around 100 degrees Celsius, which is when something begins to boil.

At the boiling point, the proteins are denatured and the virus is completely inactivated. It is essential to know this information to take it into account when preparing -or manipulating in any way- food, so that we can take the necessary measures to guarantee its health and, through appropriate practices, avoid possible food poisoning.

And it is that there are many of us who manipulate and freeze food in order to preserve it for a longer period of time, but are many of us who know what are the dangers we face when we eat certain foods?

The lack of knowledge regarding this issue is palpable and that is why we believe it is essential to know some important data such as, for example, what is the temperature at which bacteria die in the food that we are going to consume later, but it is not worth us with that. We need to take into account another series of measures that we will see later.

That said, the aforementioned 100º degrees at which bacteria die give a lot to talk about and are, in any case, part of a series of considerations to take into account when eliminating them from food and, thus, preparing food in a safe way.

Next, we answer the most common questions about how bacteria reproduce and what are the most appropriate ways of cooking to eliminate bacteria that reside in food.

How do bacteria reproduce?

There are many mechanisms by which bacteria reproduce, but the most common of all is bipartition. This form of reproduction consists of obtaining two daughter cells with identical DNA and exactly the same as the mother cell: the bacterium. This means that, depending on external factors and conditions of the food itself, bacteria tend to split or die.

The conditions in which bacteria reproduce depend on:

  • The nutritional contribution of the foods in which they reside.
  • The PH of food.
  • The amount of water they contain.
  • The temperature at which they are kept.
  • The time during which they are exposed to these conditions.

This last point is very important and you should know that the key for bacteria to reproduce lies, essentially, in the exposure time. Bacteria reproduce every 20 minutes, so the longer you keep food, the more likely it is to become contaminated.

In addition, it should also be borne in mind that the higher the quality of the food, the less it is likely to be contaminated. And the fact is that the higher the quality of the food, the lower the contamination through microorganisms.

It should also be borne in mind that bacteria reproduce in foods that are between 5º and 60º Celsius and that, therefore, it is very important to keep them at lower temperatures.

Finally, it should be noted that not all foods tend to be contaminated to the same extent and that some (such as meat, vegetables, dairy, fruit, or eggs) are capable of supporting the reproduction of bacteria at levels that are unsafe for your health and that of your family. 

This means that this type of food can be contaminated without you noticing it at first glance and that bacteria tend to reproduce in them so you have to be more careful when preparing and eating them.

How to cook to eliminate bacteria from our food?

Once we know the optimal conditions for bacteria to persist and reproduce, we must know a series of measures to cook safely and, through which, we can eliminate the bacteria that contaminate the food we prepare.

These measures to cook safely, eliminate bacteria, and thus prevent food from being contaminated are the following:

  • Store food below 5 degrees centigrade.
  • Cook above 100 degrees centigrade.
  • Avoid exposing food to between 5 and 60 degrees Celsius for two hours or more, as this is the perfect time and space for the proliferation of bacteria and food poisoning.
  • When boiling food, wait 20/30 minutes of cooking to make sure it reaches 100 degrees.
  • Do not be impatient and confirm that, above all, the eggs and milk are cooked at the right temperature and for the necessary time.
  • Take special care with meats such as turkey, chicken, or pork. Make sure the most robust parts of the breasts and thighs are done and cooked to a minimum temperature of 80 degrees Celsius in the oven.

 These foods are especially susceptible to transmitting bacteria and, therefore, we must be especially rigorous with the way we cook them.


In this article, we answered the following question: Does reheating food kill bacteria? We talked about how bacteria reproduce and how to correctly cook and handle food to eliminate any health risk.

In summary, if you follow these guidelines when cooking, you will greatly reduce the chances of suffering or causing food poisoning. At the end of the day, the safety of the food that we handle in one way or another is our greatest responsibility as food handlers.

If you have any questions or comments on the content, please let us know!


Hi, I am Charlotte, I love cooking and in my previous life, I was a chef. I bring some of my experience to the recipes on this hub and answer your food questions.