Employee & Community Health

How long can you safely keep leftovers in the refrigerator?

5/9/2019 by Katherine Zeratsky, RD, LD

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From leftovers in your lunch to planning a meal for family and friends, keeping food safe is important. Food poisoning — also called foodborne illness — is caused by harmful germs, such as bacteria, in contaminated food. Because bacteria typically don't change the taste, smell or look of food, you can't tell whether it's dangerous to eat. So if you're in doubt about a food's safety, it's best to throw it out. 

Fortunately, most cases of food poisoning can be prevented with proper cooking and food handling. To practice food safety: 

  • Quickly refrigerate perishable foods, such as meat, poultry, fish, dairy and eggs.
  • Don't let food sit more than two hours at typical room temperature or more than one hour at temperatures above 90° F. (32° C.). 
  • Uncooked foods, such as cold salads or sandwiches, also should be eaten or refrigerated promptly. 

Your goal is to reduce the time a food is in the "danger zone" — between 40° and 140° F. (4° and 60° C.) — when bacteria can quickly grow. 

Going on a picnic? Hosting a cook-out?

  • Keep cold foods in the cooler until ready to serve. 
  • To preserve quality and safety, consider resting the container or plate of cold items on a bed or bowl of ice. 
  • Have a separate cooler for drinks, since this cooler will be opened more frequently, which will affect the temperature. 

For more tips on eating outdoors and handling food safely, check out this resource from the U.S. Food and Drug Administration (FDA). 

While you shouldn't use slow cookers to reheat food, you can use them to hold foods that are already hot. Keep your food at or above 140° F. (60° C., usually on the low temperature setting). Tip: This is an option when you're feeding a large group and need to keep hamburgers or meat from the grill hot. 

Leftovers can be kept for three to four days in the refrigerator. After that, the risk of food poisoning increases. If you don't think you'll be able to eat leftovers within four days, freeze them immediately. 

When ready to eat leftovers, reheat them on the stove or in a conventional oven or microwave until the internal temperature reaches 165° F. (74° C.). 

Katherine Zeratsky, RDN, LD, has worked at Mayo Clinic 19 years. She currently helps patients at Mayo Clinic in Rochester and employees through programs at the Dan Abraham Healthy Living Center (DAHLC) and Employee Well-Being. Her areas of interest are varied from wellness nutrition to pediatrics. 

This article was reprinted with permission from Mayo Foundation for Medical Education and Research. All rights reserved.