Originally written by Megan Erickson, former SDSU Extension Nutrition Field Specialist.
South Dakota is no stranger to power outages and power surges from blizzards, ice storms and related weather conditions. If the power in your area has experienced intermittent or complete loss of electrical power, or power surges, check all freezers occasionally to be sure they work properly. To prevent freezers from shutting-off, it is best to plug the freezer into a dedicated outlet that is not connected to a circuit protected by a Ground Fault Interrupter (GFI) device as GFI’s are easily tripped by power surges, shutting off power to the freezer.
It is important to take precautions to prevent food loss in case of a power or mechanical failure or other problems. If an extended power failure is anticipated, reduce freezer temperature to -10°F or -20°F. The colder the food, the longer it takes to thaw.
Wait to open your freezer.
If power is lost, wait until power is restored before opening the freezer door. Each time the door is opened, the interior temperature increases therefore decreasing the time foods will remain safe without power. In most cases, food in a full freezer will stay frozen approximately two days. Food in a freezer that is half full may stay frozen up to one day. A freezer full of meat will remain colder longer than a freezer full of baked food.
Inspect your freezer and food closely.
If food is safe to eat, it is safe to refreeze. When you find that the freezer is off, check the temperature in two or three locations. Then, take a look at the packages of food. If foods still contain ice crystals and/or if the freezer is 40°F or lower and has been at that temperature no longer than one to two days, food that was safe when it was originally frozen should still be safe. It can be refrozen or cooked and eaten. Food held at 40°F or higher should be examined more closely. If the color or odor of thawed beef, pork, lamb or poultry is poor or questionable and you are not certain of the amount of time the food was at 40°F for higher, discard the meat.
If questionable food is consumed, the result may be food borne illness. It is difficult to tell by the odor whether vegetables, shellfish and cooked foods are spoiled. Bacteria multiply rapidly in these foods, so do not eat or refreeze any that have thawed completely.
Don't re-freeze completely thawed foods.
As a general rule, completely thawed foods should not be refrozen. If ice crystals remain in foods, it’s safe to refreeze them. The texture will be compromised, nutritional value may be lower, and flavor and color will not be top quality. If refreezing food, do so quickly to retain the best quality.
For more in-depth food safety information when the power goes out, refer to the USDA publication Keep Your Food Safe During Emergencies: Power Outages, Floods and Fires. This is an excellent publication addressing many specific types of foods as well as how to adequately clean and refresh refrigerators and freezers.