Refrigerated or frozen foods may not be safe to eat after extended loss of power. To prevent foodborne illness, prepare for emergencies and take key steps during and after power outages.

Preparation

Keep an appliance thermometer in your home. Your fridge should be below 40°F and your freezer at or below 0°F.
Freeze water and gel packs to keep your food at the appropriate temperature. Purchase a cooler to store the ice and refrigerated food if the power goes out for a long time.  

When The Power Goes Out

Keep the fridge and freezer doors closed.
If the doors stay closed, food will remain safe for 4 hours in a refrigerator, 48 hours in a full freezer and 24 hours in a half freezer.
After 4 hours put refrigerated food in a cooler filled with ice or frozen gel packs. Make sure the temperature in the cooler remains below 40°F.

After Power is Restored

IMPORTANT: Do not taste your food after an extended power outage if you are unsure of its safety. This could cause food poisoning or other foodborne illnesses. When in doubt, throw it out! 
Throw out perishable foods that were in a refrigerator without power for over 4 hours.
Make sure the fridge is below 40°F and the freezer is at or below 0°F when storing items.
If you put food in a cooler with ice or gel packs, make sure the temperature remained below 40°F or else throw it out. Throw out food that has thawed in the cooler. If the temperature remained below 40°F you can safely refreeze or cook thawed frozen food.

Throw out food with an odor or an unusual texture or color. 

Use this FoodSafety.gov chart for a complete list of what foods you should throw out and foods you can refreeze.

For further information, please visit www.cdc.gov/food-safety/foods/keep-food-safe-after-emergency.html