Some foods can be left out in room temperature for periods of time and still be safe to eat without the risk for foodborne illness or food poisoning. While pizza should be refrigerated, whether or not it's cooked, leaving it out in room temperature for short periods of time is generally okay.
Is Pizza Safe to Leave Out?
According to the U.S. Department of Agriculture (USDA), perishable food, including pizza, is not safe to eat if you've left it sitting out in room temperature overnight. This holds true even if your pizza doesn't have any meat products on it, the USDA notes. Cheese, a main ingredient in most pizzas, should be kept in the refrigerator to reduce the risk of being contaminated with foodborne bacteria.
How Long Can Pizza Sit in Room Temperature?
Just because pizza sits out for an hour or two doesn't mean you have to throw it away. Pizza can be left in room temperature for up to two hours -- or one hour in hot temperatures above 90 degrees Fahrenheit -- and still be safe to eat, according to the USDA. However, after this short period of time the pizza should be cooled to a temperature of at least 40 degrees Fahrenheit or colder to reduce the risk for foodborne bacteria to grow, the USDA notes.
How Long Should You Keep Leftover Pizza?
If you're keeping leftover pizza in the refrigerator at a temperature of 40 degrees Fahrenheit or below, it's okay to keep the pizza for three to four days, according to the USDA and the U.S. Food and Drug Administration (FDA). While you might not get sick from eating pizza that's more than four days old, you'll increase your risk for foodborne illness by doing so. Throw away any pizza that's been sitting out in room temperature for more than two hours. The FDA notes that if you keep leftover pizza in the freezer instead of the fridge, it's safe to keep it for one to two months.
An experienced health, nutrition and fitness writer, Erin Coleman is a registered and licensed dietitian and holds a dietetics degree from the University of Wisconsin-Madison. She also has worked as a clinical dietitian and health educator in outpatient settings. Erin's work is published on popular health websites, such as TheNest.com and JillianMichaels.com.