Being the type of person who shoves leftovers pizzas in the oven and leaves them there in the hopes of returning later the same day to devour the last slices can be extremely rewarding when everything goes according to plan. There’s just something special about leftover pizza. However, because I have an inability to remember the simplest of tasks, I tend to forget my pizzas in the oven overnight.
The sheer thought of knowing that the pizza has been out overnight can be a bit nasty and for good reason. A lot of food tends to spoil if it’s left at room temperature overnight, as bacterial growth starts to take place within a few hours. Visually inspecting the food isn’t enough when it’s been out for a couple of hours. It will take a long time before you can see the effects with your bare eye. So, how cautious should one be when it comes to pizza?
According to the US Department of Agriculture, you shouldn’t eat a pizza that’s been left out overnight. The risk of leaving perishable food out overnight is that it can be contaminated with food-borne illnesses. While the department’s guidelines recommend not eating any food that’s been left out for more than 2 hours, it should be noted that there’s usually little threat of food-borne illness in a pizza that’s been left out overnight but it should still be avoided to minimize the risk of food poisoning.
However, I do recommend refrigerating your leftover pizza slices at all times. If you still decide to eat a pizza that’s been left out overnight then that’s your decision. I have done it a couple of times too, and I have never felt sick. While the aim is to store all of your food in an environment that keeps them in the best possible condition, I don’t think you need to feel panic if you’re reading this because you just ate a pizza slice that you forgot to store. I just think you should do everything in your power to remember to place your leftovers in the fridge to avoid food poisoning in the future.
I’ve had food poisoning and there’s nothing good about it. It’s a horrible experience, or at least it can be and I don’t wish for anyone else to experience it.
But, as always, it’s good to be cautious and keep note of how you’re feeling. The ingredients on the pizza will determine the impact. Cheese, tomato sauce, yeast-based bread, and veggies can usually handle a night at room temperature without spoiling. Tomato sauce is too acidic to promote any bacterial growth of that kind, cheese has undergone lactic acid fermentation and has low pH, and the bread isn’t large or thick enough to retain the warmth and moist needed to grow bacillus.
Ham and other ingredients can be trickier though. Meat in general should probably be avoided if it’s been left out overnight.
| Type of Pizza | Stored At Room Temperature | Stored In Freezer | Stored In Refrigerator |
| Homemade Pizza | 2 hours | About 6 months | 3-4 days |
| Delivered Pizza | 2 hours | About 6 months | 3-4 days |
| Frozen Pizza | 2 hours | 15-20 months | If heated first: 3-4 days. If placed in the refrigerator frozen: Count 3-4 days from the time it had thawed. |
What Can Happen If You Eat Pizza That Was Left Out?
The USDA state that perishable foods stored at temperatures between 40 and 140 degrees Fahrenheit are at risk of carrying bacteria. The amount of time the food has been exposed to said temperatures drastically increases the risk of bacteria. Leaving your pizza out for a short period of time is generally okay, and you shouldn’t have to worry about eating it. However, longer periods of time can pose a certain risk.
Eating a pizza that’s been left out overnight can lead to nausea, being gaseous, stomach aches, and most other symptoms associated with food poisoning. You can experience some of the more severe symptoms or just the mildest ones and there’s a bunch of different things that determine that. The type of ingredients used, the temperature, your body’s reaction to certain ingredients, etc.
There’s no way for me to tell you how you will react, therefore, I will recommend that you avoid eating the pizza.
Does Reheating Pizza Kill Bacteria?
Most of us are familiar with the fact that cold and warm temperatures fend off bacteria. But what about a pizza that’s been left out overnight? Can you remove accumulated bacteria by reheating the pizza, making it safe to eat once again? Let’s check it out.
By reheating the pizza to temperatures above 165 degrees Fahrenheit you will kill the bacteria. This is, however, not enough. Why? Because some bacteria tend to leave spores and toxins and these aren’t killed by the temperature. So once your food has started to grow mold or bacteria, there’s very little you can do about it. The best choice is going to be to discard the food.
The risk just isn’t worth it. Yes, it’s a horrible experience to watch a pizza end up in the trash but it’s better than feeling like garbage yourself. There will be other pizzas, trust me.
The principles above also tell us why food shouldn’t be taken out of the freezer, thawed, and then put back in the freezer. While you can prevent the growth of bacteria, you can’t really reverse it.
How Long Does Pizza Last In the Box?
So, keeping a pizza out in the open for more than 2 hours doesn’t seem like the way to go. But what about a pizza that’s been refrigerated?
From the point that you pick up the pizza, eat it, and store the leftovers in the refrigerator you can expect the pizza to last for about 4 days on average before eating it becomes questionable. You can put the entire box in the fridge but there are better ways to store a pizza. My preferred method is to take the slices and place them in a Tupperware container – either stacked on top of each other as is or with a piece of baking paper between each slice.
How Can You Tell If a Pizza Has Gone Bad?
If you were to handle a pizza that’s on the edge, wouldn’t it be wise to know what to look for and what to avoid? I think so. Pizza, just like most other foods, will show obvious signs if it’s gone bad. The longer it has been sitting, the more obvious the signs will be. For instance, a pizza that’s been left in the refrigerator for a couple of weeks will probably have large mold spots, while a fresher pizza will show very little signs of spoilage.
Generally, using your nose and your fingers is a good way to identify a pizza that’s going bad. The pizza will start to dry up and the texture will change substantially as time goes. Merely changing texture isn’t enough to deem the pizza bad, as this process starts as soon as the pizza starts to cool down. It’s still considered safe to eat the pizza if it’s just the texture that’s changed.
What you’ll want to keep a nose out for is the smell. When you smell a rancid odor coming from your pizza you know that it’s been too long. It’s time to let the pizza go.
Remember, there are health risks associated with eating spoiled food so keep an eye open and if you have doubts, always go for the safest option.