If you are without power, the food in your freezer has a limited lifespan - as short as 24 hours, according to LSU AgCenter nutritionist Dr. Beth Reames.
Food can remain frozen longer, up to 48 hours, but that duration depends on specific conditions: the freezer door must remain closed; the freezer must be full or almost full; the temperature outside must be moderate; and the freezer must be large and well insulated. A half-full freezer will keep foods frozen 24 hours.
To extend the frozen period, Reames advises using dry ice. Put the ice in heavy paper or on boards inside the freezer or on top of packages. Allow 2 1/2 to 3 pounds of ice per cubic foot of space. Fifty pounds of dry ice should hold an 18-cubic foot full freezer for two days. More dry ice will be needed in an upright freezer, because it should be placed on each shelf.
Coolers with frozen gel packs are also a great help for keeping food cold if the power will be out for more than four hours.
“Never touch dry ice with your bare hands or breathe the fumes,” Reames cautions. The ice can cause severe frostbite or burns. Also, as it melts, it produces potentially toxic carbon dioxide gas.
Digital, dial or instant-read food thermometers and appliance thermometers will help you know if the food is at safe temperatures. Keep appliance thermometers in the refrigerator and freezer at all times. When the power is out, an appliance thermometer will always indicate the temperature in the refrigerator and freezer no matter how long the power has been out. The refrigerator temperature should be 40 F or below; the freezer, 0 F or below. If you’re not sure a particular food is cold enough, take its temperature with a food thermometer.
“Once food thaws and reaches 40 F, it should be cooked and eaten within two hours,” the nutritionist says, adding, “Otherwise, throw it out.” After two hours, bacteria multiply to unsafe levels.
Seafood will be among the first to thaw, so it will need attention first. Also, ground meat is likely to spoil before other meats.
Partially thawed foods with ice crystals may be safely refrozen. These foods include raw meats and poultry, cheese, juices, breads and pastries. Fruits, vegetables, fish and prepared foods can be refrozen safely, but quality may suffer.
Do not refreeze frozen dinners that have thawed. Discard all stuffed poultry. Remember, you can’t rely on appearance or odor to determine safety.