Chow line: Slow cooker safety

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I put a roast on to cook in my slow cooker and went to work. When I got home, I realized that the power had gone out at my house at some point during the day. I checked my slow cooker and the power was off, but my roast looked like it cooked fully. Can I still eat the roast?

Great question! However, I’m sorry to say that unless you are able to tell how long the roast was in the slow cooker without adequate heat, it’s best that you toss it out, according to the U.S. Department of Agriculture Food Safety and Inspection Service.  

Generally speaking, perishable foods that have been at temperatures of 40 degrees Fahrenheit or higher for two hours or more will need to be discarded to avoid the development of harmful bacteria that could cause a foodborne illness. This is because food that isn’t maintained at proper temperatures can enter the “danger zone,” a range of temperatures between 40 and 140 degrees at which bacteria grows most rapidly.

As the name indicates, a slow cooker cook foods slowly at a low temperature—generally between 170 and 280 degrees. It works by using the direct heat from the pot and the steam created from tightly covering the pot over a period of time to destroy bacteria, making the slow cooker a safe process for cooking foods, according to the USDA.

“While food is cooking and once it’s done, food will stay safe as long as the cooker is operating,” the USDA says.

But, if the power to the slow cooker goes out and you aren’t there to know how long the cooker was without power, how long the food had cooked before the power went out, or how long the food might have sat in the danger zone, bacteria could have begun to develop on the food.

So, in your case, even if the roast looks done, the USDA says it shouldn’t be eaten.

The USDA also advises the following when using a slow cooker:

  • Always thaw meat or poultry before putting it into a slow cooker.
  • Keep perishable foods refrigerated until preparation time. If you cut up meat and vegetables in advance, store them separately in the refrigerator. The slow cooker might take several hours to reach a safe, bacteria-killing temperature. Constant refrigeration assures that bacteria, which multiply rapidly at room temperature, won’t get a “head start” during the first few hours of cooking.
  • If possible, turn the cooker on the highest setting for the first hour of cooking time and then to low or the setting called for in your recipe. However, it’s safe to cook foods on low the entire time, if preparation time is limited.

Lastly, while it’s OK to use a slow cooker to keep foods warm, it’s not recommended that you reheat leftovers in a crock pot. This is because it takes too long for the leftovers to reheat to a safe temperature, creating a perfect space for harmful bacteria to form. 

As such, the USDA says it’s best to reheat food on a stove, in a microwave, or in a conventional oven until the food reaches a temperature of 165 degrees. At that point, you can then place the food in the slow cooker to keep it hot, at 140 degrees or higher.

Chow Line is a service of The Ohio State University College of Food, Agricultural, and Environmental Sciences and its outreach and research arms, Ohio State University Extension and the Ohio Agricultural Research and Development Center. Send questions to Chow Line, c/o Tracy Turner, 364 W. Lane Ave., Suite B120, Columbus, OH 43201, or

Editor: This column was reviewed by Shari Gallup, educator, family and consumer sciences, OSU Extension.

Tracy Turner
For more information, contact: 

Shari Gallup
Family and Consumer Sciences
OSU Extension