Why Use a Thermometer?

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I have received several phone calls this month and last, inquiring, “Is my food safe to eat?” Many individuals have faced situations where the power went out or their freezer malfunctioned, leaving them uncertain about the appropriate course of action for their food. Do you know the safest way to ensure your food is safe in the refrigerator and/or freezer if the power goes out? The key lies in utilizing a thermometer in both appliances. If you don’t have one, I highly recommend buying them for food safety purposes and peace of mind if you have a power failure. These thermometers are widely available at local stores and are reasonably priced.

For optimal food preservation, the temperature of the freezer should be set to a minimum of 0 degrees Fahrenheit (F), while the refrigerator should be set to a minimum of 40 degrees Fahrenheit. In the event of a power outage, rule number one is to keep the refrigerator and freezer closed as much as possible to maintain the coldest possible temperature inside. If the doors are kept closed, food will stay cold for up to four hours in the refrigerator. If the freezer is full, food could stay cold up to 48 hours and 24 hours in a freezer that is not full.

According to the Food and Drug Administration (FDA), it is imperative to determine the safety of your food after a power outage. Once the power is restored, check the thermometer in the freezer to assess the temperature. If the freezer temperature is 40 degrees Fahrenheit or below, it is safe to refreeze the food or cook. Although there might be a reduction in quality, the food is still safe for consumption. If you do not have a thermometer in your freezer, you will need to evaluate each package individually.

Refrigerated foods should be safe as long as the power outage lasted no more than four hours, the refrigerator door remained shut, and the temperature was sustained at or below 40 degrees Fahrenheit. Perishable food such as meat, poultry, seafood, dairy, cooked leftovers, cut fruits and vegetables should be thrown away after four hours with no power source. You should aways discard any food with an unusual odor, color, or texture.

This raises another question: how long does food stay good in the freezer in general? There are numerous variables that factor into the answer, extending beyond just the food type. The chart below, sourced from the National Center for Home Food Preservation, outlines the approximate times based on food quality, assuming the food was prepared and stored properly in a freezer at 0 degrees Fahrenheit or below. Essentially, frozen foods will stay good indefinitely if food safety procedures are followed, although their quality deteriorates with time. Have you ever seen freezer burn on meat and wondered if it was bad? Well, according to the FDA, it is a food-quality issue, which can occur if the food isn’t wrapped in air-tight packaging; it is not a food safety issue.

Food Approximate months of storage at 0°F
Fruits and Vegetables 8 – 12
Poultry 6 – 9
Fish 3 – 6
Ground Meat 3 – 4
Cured or Processed Meat 1 – 2

There is another food storage chart on the foodsafety.gov website that lists food, type, refrigerator, and freezer that I recommend. Please check out the sources listed for helpful information.


Food and Drug Administration


Center for Disease Control and Prevention

U.S. Department of Agriculture

For more information, contact Wendy Maynor, Extension Family and Consumer Sciences Agent, at 910-671-3276, by Email at Wendy_Maynor@ncsu.edu, or visit our website.