How many times can you reheat leftovers before it becomes risky?

There is a certain comfort in a fridge full of leftovers. Dinner is prepared. The lunch is prepared. But somewhere around day three, comfort starts to swell into anxiety — and the mental math gets a little creative. If you reheat it now, does the clock reset? Does it buy a few more days?

The answer is no. And food safety experts are pretty sick of this very myth.

The logic behind the “reheat to reset” theory sounds reasonable enough on the surface: zap the food before the bacteria get a foothold and you’ll delay the problem forever. Practical, tidy and almost completely wrong, the food safety specialists believe SELF.

At what point does reheating leftovers become risky?

Here’s what actually happens. The real danger window for leftover food isn’t in the refrigerator—it’s the stretch between cooking and cooling, when the food dips into what experts call the “danger zone” temperature, between 40 and 140 degrees Fahrenheit. “When heated food is cooled, any bacteria that enter it will rapidly replicate — some bacteria can multiply in as little as 20 minutes,” said Bill Sullivan, PhD, Showalter Professor of Microbiology and Immunology at the Indiana University School of Medicine. SELF. The longer food lingers in that area, the greater the risk that heat-resistant toxins and spores have already established themselves.

And that’s the part that reheating can’t fix. Bringing leftovers up to 165 degrees Fahrenheit will kill most active bacteria, but certain toxins and spores, such as Bacillus cereus in rice etc Clostridium perfringens in meat-based dishes, are heat-resistant and survive the microwave just fine. “Reheating reduces the risk, but it doesn’t erase it,” said Darin Detwiler, PhD, a food safety expert and associate professor at Northeastern University’s College of Professional Studies.

On top of that, every time you reheat something, you send it back through the danger zone as it cools down again. Detwiler told SELF that the smart move is to pull out only what you plan to eat right then and get the rest back into the fridge as soon as possible after the original boil.

The FDA’s position is three to four days for leftovers in the refrigeratorand no amount of wishful thinking moves that number. Dr. Sullivan said solid cooking and cooling safety habits can stretch things out by a day or two at best — not a reset, just a slight reprieve. And since the bacteria that cause foodborne illness are invisible, trusting your eyes or nose is a gamble, not a strategy.

If something smells off, looks slimy or has changed color, says Detwiler, throw it away without hesitation. And if you really want to extend the life of a meal, freeze it – before the clock runs out, not after.

The microwave is many things. A time machine is not one of them.