It’s Getting Hot: How Long Can Foods Sit Out Without Spoiling?

The summer months are a time for hosting from backyard barbecues to lakeside picnics but it’s important to avoid sampling food that has been potentially spoiled by sitting out too long, especially in the heat.

Leaving food out too long at room temperature can cause bacteria (such as Staphylococcus aureus, Salmonella Enteritidis, Escherichia coli O157:H7, and Campylobacter) to grow to dangerous levels that can cause illness,” says the United States Department of Agriculture. “Bacteria grow most rapidly in the range of temperatures between 40 °F and 140 °F, doubling in number in as little as 20 minutes. This range of temperatures is often called the ‘Danger Zone.’ “

And smelling the food that has been left out to tell if it is okay to consume likely will offer no hints as to its safety.

“Bacteria typically don't change the taste, smell, or look of food. So you can't tell whether a food is dangerous to eat,” says the Mayo Clinic.

Remember the 2-Hour Rule (1 Hour When Over 90 Degrees)

Better than performing the “smell test” is to remember the 2-hour rule when it comes to food safety.

The 2-Hour Rule: Discard any perishables left out at room temperature for more than 2 hours unless you’re keeping it hot or cold. If the food is being kept in conditions where the temperatures are above 90 degrees, then the safe time left out in the open is reduced to one hour.

The U.S. Food and Drug Administration reminds people that this 2-hour rule includes transportation time, not just when the food is sitting out for guests.

“Watch the clock with leftovers, too! Whether you’re sending “doggie bags” home with guests or are saving them for yourself, leftovers should be refrigerated as soon as guests arrive home and/or within 2 hours!” says the FDA.

The USDA says perishable food that has been left out for more than two hours at room temperature may not be safe, even though it may look and smell good.

“Never taste a food to see if it is spoiled,” says the USDA.

The Danger Zone: 40 to 140 Degrees

The danger zone for food safety is between 40 degrees and 140 degrees. This is the temperature at which bacteria can grow rapidly and even double in 20 minutes.

“The key to food safety is to keep hot food hot and cold food cold. Your goal is to lower the time that food is in the ‘danger zone,’ “ says the Mayo Clinic.

The goal in food safety is always to keep hot food hot and cold food cold:

• Keep hot food hot—at or above 140 °F. Place cooked food in chafing dishes, preheated steam tables, warming trays, and/or slow cookers. Use a food thermometer to check.
  
  
• Keep cold food cold—at or below 40 °F. Place food in containers on ice. Keep cold foods refrigerated until serving time.

“If you aren't going to serve hot food right away, it's important to keep it at 140 °F or above,” says the USDA.

The Mayo Clinic says the best course of action is to put leftovers in the refrigerator right after your meal, but that isn’t always possible at a party or picnic.

“Food that is sitting out for a party or picnic should be chilled after two hours at typical room temperature,” recommends the Mayo Clinic. “Cold perishable foods, such as chicken salad or cold meat sandwiches, can be put in serving dishes in bowls of ice.”

Food Safety in the Great Outdoors this Summer

It is much easier to practice food safety guidelines when hosting an event with a kitchen and refrigeration nearby but picnics and other events in the great outdoors pose a particular problem.

“Picnic and barbecue season offers lots of opportunities for outdoor fun with family and friends. But these warm weather events also present opportunities for foodborne bacteria to thrive. As food heats up in summer temperatures, bacteria multiply rapidly,” says the FDA. “To protect yourself, your family, and friends from foodborne illness during warm-weather months, safe food handling when eating outdoors is critical.”

Here are some FDA-safe food-handling tips for your next picnic or outdoor event:

• Keep cold food cold. Place cold food in a cooler with ice or frozen gel packs. Cold food should be stored at 40 °F or below to prevent bacterial growth. Meat, poultry, and seafood may be packed while still frozen so that they stay colder longer.
  
  
• Organize cooler contents. Consider packing beverages in one cooler and perishable foods in another. That way, as picnickers open and reopen the beverage cooler to replenish their drinks, the perishable foods won’t be exposed to warm outdoor air temperatures.
  
  
• Keep coolers closed: Once at the picnic site, limit the number of times the cooler is opened as much as you can. This helps to keep the contents cold longer.
  
  
• Don’t cross-contaminate. Be sure to keep raw meat, poultry, and seafood securely wrapped. This keeps their juices from contaminating prepared/cooked foods or foods that will be eaten raw, such as fruits and vegetables.
  
  
• Clean your produce. Rinse fresh fruits and vegetables under running tap water before packing them in the cooler — including those with skins and rinds that are not eaten. Rub firm-skinned fruits and vegetables under running tap water or scrub with a clean vegetable brush while rinsing with running tap water. Dry fruits and vegetables with a clean cloth towel or paper towel. Packaged fruits and vegetables that are labeled “ready-to-eat,” “washed,” or “triple-washed” need not be washed.
  
  
• Marinate safely. Marinate foods in the refrigerator — never on the kitchen counter or outdoors. In addition, if you plan to use some of the marinade as a sauce on the cooked food, reserve a portion separately before adding the raw meat, poultry, or seafood. Don’t reuse marinade.
  
  
• Cook immediately after “partial cooking.” Partial cooking before grilling is only safe when the partially cooked food can go on the hot grill immediately, for example at a home with a grill on the patio or deck.
  
  
• Cook food thoroughly. When it’s time to cook the food, have your food thermometer ready. Always use it to be sure your food is cooked thoroughly.
  
  
• Keep “ready” food hot. Grilled food can be kept hot until served by moving it to the side of the grill rack, just away from the coals. This keeps it hot but prevents overcooking.

As painful as it may sound, the FDA says the proper thing to do is to discard cold and hot food that has been left out at room temperature for longer than two hours or for longer than an hour when the mercury rises above 90.

While food going to waste is unpleasant, the reality is that unsafe food handling practices can lead to serious, and even life-threatening illnesses in high-risk groups such as children, pregnant women, and older adults.

“If you are not sure how long food has been sitting out, throw it away immediately,” advises the USDA.