Can you leave food in the microwave overnight?

In this article, we answer the following question: Can you leave food in the microwave overnight? We talk about what happens to food when it is left in the microwave overnight and the dangers of not storing food properly. 

Can you leave food in the microwave overnight?

No, you should not leave food in the microwave overnight. Microwaves are used to heat food, not to keep it cold, nor is it a sterile environment.

Leaving food in the microwave overnight is not recommended. When you leave your food in the microwave for a long time, you are exposing your food to an environment that is ideal for microbial growth (1).

Harmful pathogenic microorganisms (molds and bacteria) can multiply rapidly in warm and moist environments like the microwave (1-3). In this environment, they can spoil your food and potentially lead to foodborne illness (4-5).

Moreover, if you leave your food in the microwave overnight you are increasing the risk of causing it to dry out or become tough and unpalatable. Different organoleptic properties of food could be affected when placed in the microwave for too long (6).

Avoid the risk of bacterial growth and spoilage by removing your food from the microwave as soon as it has finished cooking.

If you do not want to eat immediately, it is best to transfer your food to an airtight container and store it in the refrigerator or freezer. This can help you to prevent microbial growth and ensure that the food remains safe to eat (7-8).

If you are not sure if your food is safe to eat after being left overnight in the microwave, it is better to err on the side of caution and throw it away!

What happens to food when it is left in the microwave overnight?

Several things can happen if you leave your food in the microwave overnight, for example:

  • Harmful microorganisms can grow: The warm, moist environment inside the microwave can provide a breeding ground for microorganisms, which can multiply rapidly on the surface of the food (1-3). These microorganisms can produce toxins that can make the food unsafe to eat and even can cause food poisoning or other illnesses if consumed (4-5).
  • Your food can dry out: Depending on your food and its moisture content, leaving it in the microwave overnight can cause it to dry out. This can make your food tough, chewy, or unappetizing.
  • Your food can emit unpleasant odors (off-odors) because of enzymatic degradation of microbial action (6). This is especially true for some types of food like fish or strong-smelling spices. Removing off-odors from your microwave could be a nightmare!

Thus, it is always best to remove your food from the microwave as soon as you finish cooking. 

Is it safe to eat food that was in the microwave overnight?

No, it is not safe!  If you leave your food in the microwave overnight it could be spoiled by microorganisms or enzymatic degradation resulting in the accumulation of harmful pathogens and toxins  (5, 9-11).

Eating spoiled food can cause symptoms such as nausea, vomiting, diarrhea, abdominal pain, fever, and in some cases kidney failure and even death (12).

When your food shows signs of spoilage, such as an unusual odor or texture, it is best to throw it away to avoid the risk of foodborne illness!

It is also important to know that reheating food that has been left in the microwave overnight may not necessarily make it safe to eat (7). 

Different microorganisms, spores and toxins that have accumulated on your food can remain even after reheating, as this process may not be sufficient to destroy them (7, 13-14).

It is also important to clean the microwave regularly to prevent the build-up of microorganisms and other contaminants (8). Always remember: Cleanliness helps to prevent foodborne illness!

Conclusions

In this article, we answered the following question: Can you leave food in the microwave overnight? We talked about what happens to food when it is left in the microwave overnight and the dangers of not storing food properly. 

References

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2.     Alvarez-Ordóñez A, Broussolle V, Colin P, Nguyen-The C, Prieto M. The adaptive response of bacterial food-borne pathogens in the environment, host and food: Implications for food safety. Int J Food Microbiol. 2015 Nov 20;213:99–109. https://pubmed.ncbi.nlm.nih.gov/26116419/

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4.     Aaliya B, Valiyapeediyekkal Sunooj K, Navaf M, Parambil Akhila P, Sudheesh C, Ahmed Mir S, et al. Recent trends in bacterial decontamination of food products by hurdle technology: A synergistic approach using thermal and non-thermal processing techniques. Food Res Int. 2021 Sep 1;147:110514. https://www.sciencedirect.com/science/article/abs/pii/S0963996921004130

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6.     Huis In’t Veld JHJHI. Microbial and biochemical spoilage of foods: an overview. Int J Food Microbiol. 1996 Nov 1;33(1):1–18. https://www.sciencedirect.com/science/article/abs/pii/0168160596011397

7.     Juneja VK, Huang L, Yan X. Thermal inactivation of foodborne pathogens and the USDA pathogen modeling program. J Therm Anal Calorim [Internet]. 2011 Apr 1 [cited 2023 May 3];106(1):191–8. Available from: https://akjournals.com/view/journals/10973/106/1/article-p191.xml

8.     Dudeja P, Singh A. Safe cooking practices and food safety in home kitchen and eating establishment. Food Saf 21st Century Public Heal Perspect. 2017 Jan 1;373–85. https://www.sciencedirect.com/science/article/abs/pii/B9780128017739000297

9.     Kołakowska A, Madajczak G. [Listeria monocytogenes in human infections]. Przegl Epidemiol [Internet]. 2011 Jan 1 [cited 2023 May 3];65(1):57–62. Available from: https://europepmc.org/article/med/21735837

10.   Yano K. [Other viral food poisoning (hepatitis A and E)]. Nihon Rinsho [Internet]. 2012 Aug 1 [cited 2023 May 3];70(8):1386–90. Available from: https://europepmc.org/article/med/22894078

11.   Hurst WC, Reynolds AE, Schuler GA, Tybor PT. Preventing food poisoning and food infection [Internet]. University of Georgia; 2010 [cited 2023 May 3]. Available from: https://esploro.libs.uga.edu/esploro/outputs/9949316166102959?institution=01GALI_UGA&skipUsageReporting=true&recordUsage=false

12.   Maddock EC. Food Poisoning. http://dx.doi.org/1012968/pnur199910335 [Internet]. 2014 Jun 11 [cited 2023 Apr 24];104(4344):87. Available from: https://www.magonlinelibrary.com/doi/10.12968/pnur.1999.10.3.35

13.   Pleadin J, Frece J, Markov K. Mycotoxins in food and feed. In: Advances in Food and Nutrition Research. Academic Press Inc.; 2019. p. 297–345. https://pubmed.ncbi.nlm.nih.gov/31351529/

14.   Brown KL. Control of bacterial spores. Br Med Bull [Internet]. 2000 Jan 1 [cited 2023 May 3];56(1):158–71. Available from: https://academic.oup.com/bmb/article/56/1/158/388001

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