Can you eat pizza that’s been left out overnight?

In this paper, I will answer the question: “Can you eat pizza that’s been left out overnight?” and I will highlight the potential risks related to its consumption.

Can you eat pizza that’s been left out overnight?

No, you can’t eat pizza that’s been left out overnight. 

Unfortunately, if your pizza has been sitting out for more than two hours, it is unsafe to consume. All perishable items, including pizza, are not safe to eat after resting at room temperature overnight, according to the United States Department of Agriculture (USDA). This regulation applies whether your pizza contains meat or not.

You increase your chance of contracting food-borne illnesses by keeping your pizza out at room temperature.

Perishable foods stored at temperatures between 40 and 140 degrees Fahrenheit are considered to be in a “risk zone,” according to the USDA.  The number of food-borne illnesses might double every 20 minutes when food is left out in the “risk zone”.

According to the US Department of Agriculture, while the American food supply is among the safest in the world, the Federal government estimates that there are about 48 million cases of foodborne illness annually—the equivalent of sickening 1 in 6 Americans each year. And each year these illnesses result in an estimated 128,000 hospitalizations and 3,000 deaths.

How long should you keep pizza leftovers?

According to the USDA, leftover pizza can be kept in the refrigerator for three to four days if kept at a temperature of 40 degrees Fahrenheit or below (1). 

While you won’t become sick if you eat pizza that’s been sitting out for more than four days, you will raise your risk of foodborne illness. 

Any pizza that has been sitting out at room temperature for more than two hours should be discarded (1). 

It’s safe to keep leftover pizza in the freezer instead of the fridge for one to two months, according to the FDA.

What happens if you eat Pizza that’s been left out overnight?

Perishable goods stored at temperatures between 40 and 140 degrees Fahrenheit are at danger of bacterial contamination, according to the USDA. The amount of time the food has been exposed to the temperatures raises the risk of contamination significantly. It’s usually fine to leave your pizza out for a short period of time, and you shouldn’t have any problems consuming it. Longer durations of time, on the other hand, can constitute a concern (1).

Eating a pizza that has been left out overnight can cause nausea, stomach aches, and a variety of other food poisoning symptoms. These symptoms may vary due to many factors. The type of ingredients used, the temperature, your body’s sensitivity to various components, and so on are all factors to consider.

Is it safe to eat reheated pizza?

Most of us may think that bacteria are fended off by cold and warm temperatures. But what about a pizza that has been sitting out for several hours? Is it possible to remove bacteria from the pizza by reheating it, making it safer to consume? 

Heat processing at 80°C–85°C for a few minutes is considered sufficient, with a margin of safety, to inactivate vegetative pathogenic microorganisms such as Salmonella and Campylobacter, but not bacterial spores. Although most bacterial spores do not multiply at low temperatures below 4°C, if the leftovers are not kept refrigerated, spores can grow, and hence the product is not stable at room temperature (2).

You may destroy microorganisms by reheating the pizza to temperatures exceeding 165 degrees Fahrenheit. This, however, is insufficient because some bacteria leave behind spores and toxins that aren’t eliminated by the heat. So there’s not much you can do once your food has started to sprout mold or bacteria. The best option will be to throw it away.

Does quality change if pizza sets out overnight?

You should not expect the same level of flavor as when it was ordered. However, depending on how you heat it, you can either entirely lose the flavor or keep the original one. The oven is the greatest way to reheat leftover pizza.

Other options for reheating leftover pizza for breakfast exist. A pizza stone, a grill, or a microwave can all be used.

The most practical way to reheat the pizza leftover is to use a microwave oven. The penetration depth of the radiation causes the rapid heating of microwaves and short application time. In addition, this process contributes to the reduction of temperature difference between the surface and interior of the food. However, microwave heating is not preferred in cases where hardness is important in meat and meat products because it can increase this value, it has been recommended to use the method at low-power short-time applications to solve this problem (3).

Simply use an oven if you care about the taste. It tends to keep the majority of the pizza’s natural, delectable flavor.

How to eat leftover pizza?

It should be fine to eat the leftover pizza for breakfast if it was refrigerated. A warm, reheated slice of pizza is an excellent substitute for cereal.

A bowl of cereal, for example, isn’t as healthful as a slice of pizza. Studies have revealed that pizza delivers a more balanced diet than sugar-filled breakfast.

Protein, fat, and carbs are all present in a slice of leftover pizza. In contrast, a bowl of cereal is mostly sugar with low-fat milk.


In this article, I answered the question: “Can you eat pizza that’s been left out overnight?”. 

If you leave pizza leftovers out at room temperature overnight, they will deteriorate. Refrigerating it, on the other hand, may keep it edible for a few days. Pizza leftovers, for example, can be eaten in the morning if they are preserved properly.

Please contact me if you have any queries about this topic.


  1. Leftovers and Food Safety. United States Department of Agriculture. 2020.
  2. Ahmed, Jasim, and Hosahalli S. Ramaswamy. Microwave pasteurization and sterilization of foods. Handbook of food preservation. CRC Press, 2020. 713-732.
  3. Kutlu, Naciye, et al. Impact of different microwave treatments on food texture. J Text Stud, 2021.