I recently had a call from a South Carolina resident who lost power for more than 24 hours and wanted to know whether the foods in her freezer would be safe to eat. This is a very common problem in South Carolina winters and could easily affect you in the coming months.
The best plan for dealing with food safety and power outages is plan ahead.
In preparation for bad weather, fill freezer bags with ice for ice packs or purchase freezer-pack inserts. Have coolers available and easily accessible; Styrofoam ones work great. Have a calibrated food thermometer on hand for checking the temperature of your potentially hazardous food. Before an emergency occurs, find out where to buy blocks of ice or dry ice. Before an expected storm, turn refrigerators and freezers to the coldest settings.
When the power goes out, unplug the freezer and refrigerator and other appliances, to protect them from power surges when the power returns. Make sure everyone in your household knows not to open the refrigerator or freezer doors. Keeping the doors closed will keep the food cold for a longer period of time. Wrap the refrigerator or freezer in blankets to create extra insulation. Make sure blankets don’t touch the compressor. If power possibly will be off for more than 2 to 4 hours, re-pack refrigerated items into coolers with plenty of ice.
Depending on the size of the freezer, how full it is, and how well insulated it is, items in it potentially can stay frozen for 2 to 4 days. A full freezer (operating at 0°F) will keep foods frozen for about 48 hours if the doors stay closed. A half-full freezer can only be expected to keep food frozen for a maximum of 24 hours. For extended power outages use blocks of dry ice in the freezer. A fifty-pound block of dry ice will keep the contents of a full 18 cubic foot freezer frozen for 2 days. Remember to wear gloves or use tongs when handling dry ice.
When the power returns, check the internal temperatures of all perishable foods with a calibrated food thermometer. Discard any perishable food that has been above 40°F for more than 2 hours.