The Food Safety Rules to Know When the Power Goes Out

“Power outages are more than an inconvenience. They can create food safety hazards that families cannot see, smell, or taste, and they can also put hundreds of dollars’ worth of food at risk at a time when families are already dealing with high grocery prices,” says Dr. Darin Detwiler, food safety advocate, author, and educator at Detwiler Consulting Group. “Preparation matters both for protecting health and for protecting the value of the food we bring into our homes.” 

According to the Centers for Disease Control and Prevention (CDC), foodborne disease sicken an estimated 1 in 6 Americans (or 48 million people) every year; 128,000 are hospitalized, and 3,000 die. Knowing how long food in the fridge remains safe to eat during a power outage depends on the type of food and duration of the outage. The vital information in this guide can both help keep your household healthy and minimize the cost of replacing thrown away frozen and refrigerated foods. Here is what you need to know about food safety during a power outage.

Monitoring Fridge and Freezer Temperatures

The temperatures inside your refrigerator and freezer is key when determining whether your food is safe to eat after a power outage. According to the CDC, refrigerators should be kept at or below 40 degrees Fahrenheit and freezers should be kept at or below 0 degrees Fahrenheit. However, because many refrigerators and freezers do not have a thermostat—and those that do may not provide accurate temperature readings—it can be difficult to know exactly how cold it is inside the appliance’s compartments.

A couple of inexpensive appliance thermometers will let you easily monitor the temperature of your refrigerator and freezer to determine if the food stored inside is still safe to eat. Choose a wireless refrigerator thermometer with a tabletop display or an analog model with an easy-to-read temperature dial, like this Rubbermaid refrigerator thermometer. Fridge and freezer thermometers can also cue you into issues with your appliances even when the power is running, such as if your fridge isn’t cooling and needs to be repaired or replaced.

If you want to go old-school with a monitoring method that’s also a good idea pre-vacation, use the frozen penny trick: Fill a cup with water, freeze it, and then place a penny on top of the ice. If the penny is frozen in the middle of the cup, that means there was a power outage and your food may not be safe to eat. 

How Long Will Food Last During a Power Outage?

Keep in mind that the longer the power is out, the more refrigerated and frozen foods will become unsafe to consume. “During an emergency, we are protecting more than groceries. We are protecting the health of the people we love, particularly those most vulnerable to serious illness, while also protecting the economic value of food that families worked hard to purchase,” says Detwiler. 

Here are general guidelines for food safety during a power outage based on elapsed time. 

4 Hours

What’s the most important food safety rule when the power goes out? “Do not open your refrigerator or freezer,” says Jill Roberts PhD, MS, MPH, CPH, Professor at the College of Public Health, University of South Florida. “Both can maintain safe temperatures for about 4 hours with no power.” 

When the doors are left closed, the food inside a standard refrigerator should stay cold for approximately 4 hours. Since a full fridge and freezer maintains its temperature longer, Detwiler suggests that if you know that a power outage is possible, “containers of frozen water can fill unused space and provide additional cooling capacity.” If the power outage lasts longer than a few hours, move milk, meats, eggs, and other perishable items to a cooler filled with ice to keep them cold. 

24 Hours

If your freezer is at least half full and remains closed, it should be able to maintain its recommended 0-degree Fahrenheit temperature for about 24 hours. If your power has been out for a full day, purchase a block of dry ice from a grocery or big box store and place it in the freezer to help the compartment maintain 0 degrees Fahrenheit. If you have a wireless thermometer, check the tabletop monitor periodically to monitor the temperature, but avoid opening the door to check an analog thermometer often as opening it will raise the temperature. Detwiler says: “Think of the cold air inside as a limited resource: every time the door opens, some of that protection is lost.” 

48 Hours

When the door remains shut, a full freezer should maintain the recommended 0-degree Fahrenheit temperature for about 48 hours, or 2 days. However, if you still have no electricity after 2 days, the temperature inside the freezer may rise, causing frozen items to begin defrosting. If the power has been out for a while—or you know that a long outage is likely—purchase some dry ice before you reach 48 hours. About 50 pounds of dry ice will help a fully stocked,18-cubic foot freezer cold for about two days.

Before a Power Outage

“Preparation should happen before the lights go out,” says Detwiler. “Preparation before an outage gives households the information and tools to make safer, more confident decisions when the power goes out.” Here’s what you can do today so you are ready for the next power outage.

Refrigerated Foods

Keep refrigerated and frozen food cold and safe with food safety recommendations from FoodSafety.gov so you are ready when the electricity cuts out.

• Set your refrigerator temperature to 40 degrees Fahrenheit or lower and your freezer temperature to 0 degrees Fahrenheit or lower.
• Freeze refrigerated food that won’t be needed immediately so they can stay at a safe temperature longer. 
• Monitor fridge and freezer temperatures with an appliance thermometer to ensure accuracy.
• Have coolers, ice cubes, and gel packs available and ready for use.
• Identify local retailers that sell dry ice with this helpful local search tool.

Emergency Foods

“Families should also think ahead about what they would eat if refrigeration and normal cooking were unavailable,” says Detwiler. “Shelf-stable foods and a supply of safe drinking water can reduce the temptation to repeatedly open the refrigerator or freezer.” Roberts agrees: “I would highly recommend keeping a stash of non-perishable foods. Store them in a cool, dry area.” 

Here are more emergency food prep tips from FoodSafety.gov: 

• Check the expiration dates of your non-perishable foods. 
• Store a 3-day supply of water—3 gallons—for each member of the household.
• Protect non-perishable food from rodents, and store far away from petroleum products and range or fridge exhausts. 

Not sure what to buy? Here are suggested emergency food supplies from Ready.gov. 

During a Power Outage

During a power outage, help maintain food safety and decrease the likelihood of food spoilage and foodborne illnesses with the following.

• Use a wireless refrigerator thermometer so you can avoid opening the fridge and freezer doors and keep compartment temperatures as low as possible.
• Place blocks of ice or dry ice in the fridge and freezer to keep foods colder longer.
• Move foods from the refrigerator to a cooler if the power remains out for 4 hours. 
• If you have a gas stove or can cook food outside, cook and eat meat stored in the fridge before it has a chance to spoil. Use a food thermometer to verify that it is cooked to a safe internal temperature.
• During a summer power outage, discard any perishable food items that have been left out for longer than 1 hour in indoor temperatures higher than 90 degrees Fahrenheit.

After Power Is Restored

Perishable refrigerated food that has been stored at a temperature greater than 40 degrees Fahrenheit for 4 hours or more must be thrown out. While it may be tempting, Detwiler warns: “Never taste questionable food to determine whether it is safe. Unfortunately, the pathogens that cause foodborne illness do not necessarily change the appearance, smell, or taste of food. Something can look perfectly normal and still be unsafe.”

Food in the freezer that is still covered in ice crystals can be refrozen or cooked. If you have an appliance thermometer in your freezer that reads at or below 40 degrees Fahrenheit once the power is restored, you can also safely refreeze or cook any of the freezer contents.

If you aren’t sure, Detwiler advises: “When there is genuine uncertainty about the safety of a perishable food, the appropriate message remains: When in doubt, throw it out.”

Foods to Toss

When cleaning out the refrigerator after a power outage, any perishable food items that have been stored at temperatures above 40 degrees for 4 or more hours need to be thrown out. (Plus, all containers and surfaces that were in contact with spoiled food need to be sanitized.) These perishable foods include:

• Milk
• Eggs
• Poultry
• Meats
• Seafood
• Lunch meat
• Casseroles
• Soft, shredded, and low-fat cheeses
• Cut fresh fruits
• Cut fresh vegetables
• Opened creamy dressings

Foods to Keep

While many items stored in the refrigerator must be discarded after a power outage lasting four or more hours, there are several foods that are safe to keep if kept above 40 degrees for 2 or more hours. These include:

• Uncut fresh fruits
• Uncut fresh vegetables
• Opened or unopened canned fruits
• Opened or unopened fruit juices
• Hard cheeses
• Butter and margarine
• Peanut butter
• Soy and barbecue sauces
• Opened vinegar-based dressings
• Bread, muffins, and cakes

 

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