Here's When Your Leftover Pizza Becomes Unsafe To Eat

One of the best parts of ordering a pizza — besides not having to cook — might actually be a second time in everything that's left over. But if you aren't careful, you could expose yourself to foodborne illness by either not properly storing leftovers or eating them too long after they were cooked. Perishable foods don't last forever, so next time you go to grab a slice of pizza from the fridge or that pizza box you left on the counter, check yourself to make sure it won't make you sick.

Pizza has three main ingredients: dough, sauce, and cheese. Perishable foods like cheese should never be kept out at room temperature for more than two hours. Room temperature falls in food's "danger zone," which is the range between 40 and 140 degrees Fahrenheit where food is most susceptible to bacteria growth. If the pizza has been left out, don't consume it after the two-hour window has passed, but even if it's been kept refrigerated, the USDA says it should be consumed within four days.

There are additional steps you can take to keep that leftover pizza as fresh as possible for those four days. First, refrigerate it within two hours of receiving it. It's a myth that reheating it will make it safe to eat again; certain bacteria (such as Bacillus cereus, which can grow on cheese) produce toxins once they're left out for a while, which heat can't kill. Second, always make sure any leftover pizza slices are well-wrapped in cling film or aluminum foil. This not only helps prevent bacteria growth but it also ensures the pizza won't take on any interesting odors from foods that are already in the refrigerator.

If you don't plan to eat the pizza within the four-day window, you can freeze it. Just make sure to wrap it well or put it in an airtight container to prevent freezer burn; it will stay fresh for up to two months but technically will be safe to eat indefinitely (just know that it will lose its flavor and texture the longer it sits. And when you do thaw it, thaw it in the refrigerator; it's not safe to thaw leftovers on the counter because they can quickly grow bacteria.