Leftovers: How Long They Keep and How to Reheat Safely

Good leftovers come down to three habits: get food into the fridge fast, eat it within a few days and reheat it until it is hot all the way through.

USDA’s Food Safety and Inspection Service (FSIS) puts it plainly: not cooking food to a safe temperature and leaving food out at an unsafe temperature are the two main causes of foodborne illness. Leftovers sit right at the point where both can go wrong.

Get leftovers into the fridge within 2 hours

The clock starts when the food comes off the heat. FSIS says bacteria grow rapidly between the temperatures of 40 °F and 140 °F, and its Danger Zone page adds that bacteria can be doubling in number in as little as 20 minutes in that range.

So the rule is short. Within 2 hours of cooking food or after it is removed from an appliance keeping it warm, leftovers must be refrigerated. On a hot day the window shrinks: FSIS says to throw away perishable food left at room temperature for more than 2 hours (1 hour if the temperature is over 90 °F, such as at an outdoor picnic during summer).

If you are serving food over a longer stretch, FSIS says hot food must be kept hot at 140 °F or warmer, and cold perishable food, such as chicken salad or a platter of deli meats, should be kept at 40 °F or below.

Cool it fast in shallow containers

A big pot of chili cools slowly in the middle, and that slow cooling is the problem. FSIS says to divide large amounts of food into shallow containers so food reaches 40 °F or below as fast as possible. Its Danger Zone page says leftovers must be put in shallow containers for quick cooling and refrigerated at 40 °F or below within two hours.

A few practical moves from the same FSIS page:

• Split soup or stew into several small containers instead of one big one.
• Slice whole roasts or hams into smaller parts before chilling.
• Cut a cooked turkey into smaller pieces: slice the breast meat, and leave legs and wings whole.
• You don’t need to wait for food to cool on the counter. FSIS says hot food can be placed directly in the refrigerator.

Then cover it. FSIS says to cover leftovers, wrap them in airtight packaging, or seal them in storage containers, which helps keep bacteria out, retain moisture and stop leftovers from picking up odors. If you cook in batches, our meal prep basics guide has ideas for portioning as you pack.

How long leftovers keep

The headline number: FSIS says leftovers can be kept in the refrigerator for 3 to 4 days or frozen for 3 to 4 months. It adds that frozen leftovers are safe indefinitely but can lose moisture and flavor when stored for longer times.

The refrigerator column below comes from the FSIS refrigeration storage chart, and the freezer column from the FSIS freezer storage chart (0 °F), which notes that freezer storage is for quality only.

Label each container with the date you cooked it. On day four, if it is still there, it goes.

Thaw frozen leftovers safely

FSIS lists three safe ways to thaw leftovers: the refrigerator, cold water and the microwave oven.

• Refrigerator: slowest, but the food stays safe the whole time. FSIS says that after thawing, the food should be used within 3 to 4 days or can be refrozen.
• Cold water: faster, but the leftovers must be in a leak-proof package or plastic bag. Foods thawed this way should be cooked before refreezing.
• Microwave: fastest. FSIS says to continue to heat it until it reaches 165 °F as measured with a food thermometer.

Never leave them on the counter to thaw: FSIS says perishable foods should never be thawed on the counter, or in hot water.

Short on time? FSIS says it is safe to reheat frozen leftovers without thawing; it just takes longer. Our guide to thawing food safely covers each method in more detail, and freezer-friendly meals explains what to freeze in the first place.

Reheat leftovers to 165 °F

Whatever the method, the target is the same. FSIS says when reheating leftovers, be sure they reach 165 °F as measured with a food thermometer, and to reheat sauces, soups and gravies by bringing them to a rolling boil. Covering leftovers while reheating retains moisture and helps the food heat all the way through.

Refreezing leftovers

FSIS says it is safe to refreeze any food remaining after reheating previously frozen leftovers to the safe temperature of 165 °F. And if you thaw a big container in the fridge but only need some, you can take out your portion and refreeze the rest without reheating it.

Leftovers checklist

• Refrigerate leftovers within 2 hours (1 hour on a day above 90 °F)
• Divide large batches into shallow containers
• Cover, wrap or seal every container
• Write the date on the lid
• Eat or freeze refrigerated leftovers within 3 to 4 days
• Thaw frozen leftovers in the fridge, in cold water or in the microwave, never on the counter
• Reheat to 165 °F and check several spots with a food thermometer
• Bring soups, sauces and gravies to a rolling boil
• When in doubt, throw it out

Packing leftovers for tomorrow’s lunch? See packed lunch food safety. For more on keeping food safe at home, browse Food Safety at Home.