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how long will cooked food stay safe, hand washing water temperature

Created date

November 23rd, 2015

Q. How long will cooked food stay safe to eat when it is stored in an insulated bag?

A. Some people rely on insulated bags in order to keep hot foods hot and cold foods cold. These bags by themselves may be fine for two hours or less—as that is the critical cut-off point when bacteria can grow to dangerous, illness-causing levels. To stay safe for longer than two hours, hot foods need to stay at 140°F or higher, and cold foods need to stay at 40°F or below. 

For hot foods, use an insulated container with a tight-fitting lid as opposed to a bag with a zipper or Velcro seal. For cold foods, place at least two cold sources such as frozen gel packs or a frozen bottle of water in the bag—one on top and one below the food packages. In addition, if you plan to transfer your insulated bag to a refrigerator, leave the top open so that the cold air can reach the food. No matter how careful you are, bacteria can always grow, so if you have common signs of foodborne-illness such as fever, stomach pain, vomiting, or diarrhea that don’t seem to be resolving after a day or two, call your doctor.

Q. Hand washing is always recommended for disease prevention, but what temperature should the water be?

A. Although some sources, including the National Restaurant Association Educational Foundation, recommend that water temperature be at least 100 degrees Fahrenheit, the Centers for Disease Control and Prevention (CDC) evaluated the scientific evidence and found that temperature does not matter. What matters, the CDC discovered after reviewing numerous studies, was that length of time and thoroughness of technique were effective in killing germs, whether the water was hot, warm, or cold. Hands should be washed for at least 20 seconds—roughly the length of time it takes to sing the “Happy Birthday” song twice through. In addition, all areas of the hand should be lathered well, including under the fingernails.


Health and wellness experts practice exclusively at Erickson Living communities all over the U.S. This month our expert is

Robert Stewart, M.D.

Medical Director

Wind Crest

Highlands Ranch, Colo.

Dr. Stewart received his bachelor’s degree from Texas A&M University in College Station, Tex., and his medical degree from Baylor College of Medicine in Houston, Tex. He completed his residency at Floyd County Hospital in Rome, Board-certified in family medicine, he joined Wind Crest in November 2013.