The One Reason You Should Stop Putting Hot Foods in the Fridge

Every time I get a rotisserie chicken, the leftover bones go into the Instant Pot the next day. Afterward, I’m never sure what to do with the containers of steaming chicken broth when I’m done. Is it safe to put hot foods right into the fridge or freezer or do they require a cooling-off period? Here's what the experts say.

“Refrigerators are good at keeping things cold, though they are not very good at making things cold,” says Keith Schneider, a professor of food safety at the University of Florida. “So, if you have a small plate of leftovers, there’s no problem putting that in your refrigerator. If you have a gallon of fresh, homemade spaghetti sauce that’s just come off the stove, that would not be OK to put in the refrigerator.”

Schneider says he once made a gallon of homemade spaghetti sauce and didn’t let it cool very long before putting it in the refrigerator. “When I woke up the next morning, my refrigerator and all the contents were at a balmy 70°F. I had to throw everything out,” he says.

Putting a large amount of very hot food in the fridge causes the entire refrigerator to warm up. And that offers the perfect environment for microbes to grow on everything inside the fridge: the “danger zone.”

What Is the Danger Zone?

To keep food safe, it’s critical to keep them from reaching temperatures between 40°F (4°C) and 140°F (60°C), a range called the “danger zone” by the U.S. Department of Agriculture. At those temperatures, bacteria multiply more quickly.

“When food is left in the ‘danger zone’ for an extended period, harmful—even deadly bacteria, such as E.coli and salmonella—can double every 20 minutes, which means that a small number of bacteria can quickly grow into a large population,” says Darin Detwiler, professor of food policy and corporate social responsibility at Northeastern University.

You can let hot food cool outside the refrigerator but have a food thermometer handy. Once it has reached 140°F, don't let it sit out for more than two hours. Quickly try to cool it down to below 40°F. Food kept in the danger zone for over two hours should be discarded. 

4 Tips For Cooling Food Down Quickly

There are things you can do to cool down a large portion of hot food safely:

1. Divide hot food into shallow containers before refrigerating. Smaller portions allow food to cool more quickly. 
2. Don’t stack the containers in the fridge until the food is completely cooled. This can cause them to take longer to cool as the heat moves into upper containers.
3. Make sure your refrigerator is set to 40°F or below and make space for the warm containers so there’s adequate airflow on all sides.
4. Run the containers under cool running water or submerge them in an ice bath to drop temperatures more quickly.

What To Do if You Forget 

It’s happened to all of us. You leave hot food on the counter to cool and then totally forget about it until hours later, or even the following day. How do you know if it’s safe to eat?

“When in doubt, throw it out,” says registered dietitian nutritionist Jen Bruning, MS, RDN, LDN, spokesperson for the Academy of Nutrition and Dietetics. “Perishable foods that are forgotten on a counter, in the turned-off oven, on the picnic table, etc. should be thrown away if not refrigerated promptly. With unrefrigerated leftovers, there’s a higher risk of becoming ill or making a loved one ill. Don’t take chances with yourself or others.”