The two-hour rule for keeping leftovers safe to eat

Preparing large quantities of soup, stir-fried dishes and stews, or saving takeaway meals for later, is a convenient way for households to reduce cooking time. However, improper storage and reheating can increase the risk of foodborne illness.

Dr. Vanessa Coffman, alliance director at the U.S.-based nonprofit Stop Foodborne Illness, told Real Simple that the main safety concern is not how often leftovers are reheated, but how long they remain unrefrigerated.

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She explained that reheating food repeatedly may affect its taste and texture, but does not automatically make it unsafe. The greater risk comes from allowing perishable foods to spend too much time at room temperature.

According to Coffman, perishable foods should not be left at room temperature for more than two hours in total. When temperatures reach 32°C or higher, the maximum safe period falls to one hour.

The limit applies to the cumulative time food spends outside refrigeration, including during serving and subsequent meals.

For instance, mashed potatoes left on a dining table for an hour have already used half of the recommended two-hour allowance. If they are reheated the following day and remain at room temperature for another hour, they have reached the limit and should be discarded.

Because repeated reheating can make it difficult to track this accumulated time, Coffman advises dividing leftovers into smaller portions before refrigerating them. Only the amount needed for each meal should be reheated, while the remainder stays chilled.

Experts cited by Hindustan Times also recommend heating leftovers thoroughly until they are steaming hot throughout, ideally reaching an internal temperature of 74°C.

How long can leftovers be stored?

Coffman recommends discarding perishable foods once they exceed the two-hour cumulative limit at room temperature, or one hour in conditions of 32°C or above.

Most refrigerated leftovers should be consumed within three days or transferred to the freezer by that time. Food kept in the refrigerator beyond the recommended period should be thrown away.

Homemade whipped cream and meat-based gravies have a shorter recommended storage period and should be eaten within one day of refrigeration or discarded.