Picnic and Camping Coolers

• Styrofoam coolers will keep food cool for a few hours. An insulated camping cooler made of plastic or metal may maintain temperatures at or below 40 F, the temperature recommended by the U.S. Department of Agriculture to retard food spoilage. Food is also considered safe to eat if it contains ice crystals. Group similar foods together when possible. Store more perishable items, such as milk, eggs and meat, near frozen foods to keep them at or below 40 F. Keep frequently used items near the top of the cooler to reduce the amount of time spent searching for a needed item.

Basements and Alternatives

• Basements, storage areas and garages are often several degrees cooler than living areas but are seldom cold enough to store perishable foods, such as meats and eggs, for more than two hours. Camping and picnic coolers are the best choices for storing food in these areas, but placing perishable items inside two nested cardboard boxes and closing their lids is a viable alternative. Place the cooler or box on a table, shelf or other elevated surface if flooding or rainwater could come in contact with the food.

Refrigerators and Freezers

• Keep the doors and lids closed on refrigerators and freezers during a power outage. A refrigerator will keep its contents cold for about four hours. Discard perishable foods, such as milk, meat and leftovers, when the power is back on. A full freezer will keep food at a safe temperature for about two days, while a half-full one will keep it safe for 24 hours. Adding blocks of ice will help keep temperatures lower for several hours longer. The length of time depends on the temperature of the contents and the outside temperature. Dry ice placed on top of a freezer's contents may keep food at safe temperatures for several days.

Ice and Alternatives

• Make or buy extra ice if you have time for advance preparation. Block ice melts more slowly and keeps temperatures lower for longer. Cubes melt quickly but also chill food faster. Make your own block ice by filling clean empty plastic milk jugs with water and putting them in the freezer. As a bonus, you will have cool drinking water after the ice melts. Refreezable gel packs designed for use in coolers also work well at keeping temperatures near 40 degrees. Handle dry ice carefully if you plan to use it instead of ice made from water. Always wear heavy gloves and never touch it with your bare hands when handling it to avoid frostbite. Ensure good ventilation when using dry ice. The carbon dioxide it produces as it sublimates displaces oxygen, creating a suffocation risk to people in the immediate area.