CFAES Give Today
News Releases Archive (Prior to 2011)

College of Food, Agricultural, and Environmental Sciences


Chow Line: 'Smell test' not safe after power outage (for 7/14/11)

August 5, 2011

My parents' electricity often goes out, sometimes for long periods. Mom says food in the refrigerator and freezer is fine unless it smells bad. What would you tell her?

Food safety experts say to use the hands of a clock -- not your nose -- to determine whether perishable food is safe after a power outage.

As long as you keep the refrigerator and freezer doors closed, the refrigerator will keep food cold enough to remain safe for about four hours. A full freezer will keep food safe for about 48 hours. If the freezer is only half full, it will keep cold enough for about 24 hours.

Unfortunately, many people are in your mother's camp. According to a survey of more than 1,000 people, 65 percent said they used their sense of smell to decide whether perishable foods were safe after a power outage. Only one-third of the respondents said they were aware that they should throw away perishable refrigerator foods after a four-hour outage. The study was published recently in Food Protection Trends.

The U.S. Department of Agriculture's Food Safety and Inspection Service has several recommendations regarding extended power outages:

  • Keep an appliance thermometer in the freezer in a spot that you can get to easily. When the power comes back on, look at the thermometer. If it's still under 40 degrees F, that tells you the food is safe and can be refrozen.
  • However, any foods (in the refrigerator or the freezer) that have come into contact with raw meat juices should be thrown away.
  • Don't wait for an outage: Find out now where you can buy dry ice. It can be used to keep foods cold in both the refrigerator and freezer during extended outages.

Another idea: Always keep a plastic zipper bag with a few ice cubes in the freezer. After a power outage, take a look: If the cubes are still partially intact, you know the freezer didn't get above 32 degrees for very long. If they've obviously completely melted, it's a good idea to carefully look at each food item: Items that still have ice crystals are safe to refreeze.

In the refrigerator, most items should be thrown away if they've been held above 40 degrees F for more than two hours. Be conservative: If in doubt, throw it out. It may be disheartening, but it's better than a experiencing several days of food-borne illness.

For more information, including a list of what to save and what to throw away after a power outage, see the FSIS fact sheet, "Keeping Food Safe During an Emergency," at

Chow Line is a service of Ohio State University Extension and the Ohio Agricultural Research and Development Center. Send questions to Chow Line, c/o Martha Filipic, 2021 Coffey Road, Columbus, OH, 43210-1044, or

Editor: This column was reviewed by Lydia Medeiros, food safety specialist with Ohio State University Extension, scientist with the Ohio Agricultural Research and Development Center, and professor of human nutrition in the College of Education and Human Ecology


Martha Filipic
Lydia Medeiros