Think these foods are safe to leave out? Food safety experts say think again.
Reviewed by Dietitian Katey Davidson, M.Sc.FN, RD, CPT
Key Points
- Perishable foods can become unsafe after sitting in the danger zone for two hours.
- Pizza, rice, baked potatoes, produce and deli meats are particularly risky.
- Proper cooling and refrigeration can help reduce your risk of foodborne illness.
Have you ever walked into the kitchen in the morning to discover you left some dinner leftovers sitting on the counter all night? Oops. But it happens to the best of us!
The question is, can you still eat it? Unfortunately, according to food-safety experts, the answer is most likely no. Perishable food that is allowed to hang out in the “danger zone” (40° to 140°F) for two hours or more could become a food-safety risk. That’s because the bacteria that cause foodborne illness thrive and multiply at this warm and cozy temperature range.
Reheating and freezing can’t make the food safe again, either. Once a food has lingered in the danger zone long enough for bacteria to multiply to unsafe levels, most can’t be killed off with heat or cold.
While you may think of foods like milk or raw meats as risky foods to leave out, there are other surprising foods that are also high risk. Read on to find out which unexpected foods food-safety experts say you should keep an eye on and how to store them properly to reduce the risk of foodborne illness.
1. Pizza
Pizza and parties have become almost synonymous, with this popular dish often serving as the go-to entree when you’re feeding a crowd. Many people also tend to let it sit out for a long time—but that’s a no-no according to food safety experts.
When you think about it, it makes sense. Pizza is made with cheese and often contains toppings like meat and cooked vegetables, which all pose a food-safety risk. Bacteria can multiply rapidly when these foods are left in the danger zone for more than two hours, with some bacteria doubling in number in as little as 20 minutes under certain conditions, says Vanessa Coffman, Ph.D.
Since pizza boxes are large and take up a lot of fridge space, you may be tempted to leave leftover pizza on the counter overnight. “Leaving pizza out overnight provides ample time for bacteria to multiply to potentially unsafe levels and can increase the risk of foodborne illness,” says Coffman. So, if you want to be able to enjoy your pizza leftovers the next day, move the pizza to a plate and put it in the fridge within two hours. The next day, reheat it to an internal temperature of 165°F.
2. Foil-Wrapped Baked Potatoes
Baked potatoes are a classic meal with endless toppings options. They’re also a breeze to bake, thanks in part to their foil wrapping. But what makes them easy to cook can also create an environment where bacteria can grow if they’re left at room temperature for too long.
“Potatoes are moist and low in acid, and when they are left tightly wrapped in foil at room temperature, the foil creates a low-oxygen environment where Clostridium botulinum spores can grow and produce toxin,” says Ashley Miller, M.P.H., CP-FS, REHS/RS.
In fact, baked potatoes were at the center of a large botulism outbreak in the ’90s. “In a documented 1993 outbreak, 17 people developed botulism after eating a potato-based dip made with foil-wrapped baked potatoes that had been left at room temperature for several days,” shares Miller. “The best way to reduce the risk of foodborne illness from baked potatoes is to keep them hot until served or cool them promptly with the foil loosened,” she adds.
3. Fresh-Cut Produce
Many fruits and vegetables can be stored safely on the counter, which is why you might assume they’re OK to leave out once they’re cut. Unfortunately, the food-safety risk changes greatly once produce meets your kitchen knife. “Cut fruits and vegetables should be refrigerated within two hours. This includes produce served on a vegetable tray as well as fruits and vegetables that have been cut or prepared as part of a meal,” says Coffman.
“Once fruits and vegetables are cut, their protective outer surfaces are broken, making the exposed surfaces more susceptible to bacterial contamination and growth,” Coffman adds. In fact, fresh-cut produce is included in the FDA’s food traceability list because it has historically been linked with foodborne illness outbreaks.
4. Deli Meat
Deli meats are a convenient sandwich staple for lunches. In fact, on average, U.S. adults report consuming about 8 pounds of deli meat each year.
While it’s perfectly fine to pack deli meat in your on-the-go lunches, leaving your lunch bag at room temperature all morning gives bacteria the ideal environment and plenty of time to grow.
But don’t worry, there’s no need to switch to PB&J yet. “Just be sure to keep them cool if not eating right away,” says Mary Angela Miller, M.S., RDN, LD. To keep your lunch cold when you’re away from home, the USDA suggests using at least two cold sources, like two frozen gel packs or a frozen gel pack and a frozen bottle of water. When packing your lunch bag, sandwich the food you want to keep cold between the two cold sources. Of course, if there’s a fridge available, use it.
5. Cooked Rice
Cooking up a big pot of rice is a great way to get ahead on meal prep for the week, but this pantry staple can pose a serious food-safety risk if left out too long.
“Rice can harbor spores of Bacillus cereusa bacterium that can survive the cooking process,” explains Coffman. Other starchy foods like pasta and potatoes can also harbor this same bacteria, but it loves rice in particular because the small pieces provide more surface area for it to grow. “When cooked rice is left at room temperature, these spores can germinate and allow the bacteria to multiply and produce toxins that can cause foodborne illness,” she adds.
Luckily, you can keep your rice safe by taking steps to cool it correctly. Dividing food into smaller portions or shallow containers can help, says Mary Angela Miller. She adds that you can speed up the process by placing your container of cooked rice in an ice-water bath, stirring it for a few minutes and then placing it right into the fridge.
Our Expert Take
Food provides the nourishment we need to go about our daily lives, but it can also harbor harmful bacteria when it isn’t handled properly. Keeping perishable foods out of the “danger zone” is one of the simplest ways to reduce the risk of foodborne illness. So, the next time you’re tempted to leave pizza, cooked rice or another perishable food on the counter, don’t.