These best practices were written by Lauren Sommer form KQED on all things to do in preparation for power outages.
Before a Power Shutoff
Put ice packs or frozen containers of water in your fridge or freezer to help keep the temperature low. You can also buy dry ice or block ice to keep the food cold.
Freeze items you don’t need right away, like meat, poultry and leftovers.
Keep the food bunched together in your freezer to help it stay cold longer
During a Power Shutoff
If you think the power will be out for longer than four hours, you can transfer perishable food to the freezer or to a cooler with ice packs to extend its life. Make sure to keep replenishing the ice in the cooler to keep it cold.
Keep the fridge and freezer doors closed as much as you can.
Put a thermometer in your fridge. The magic number is 40 degrees Fahrenheit, because above that temperature, bacteria can proliferate. If the temperature rises above 40 degrees, the food should be discarded after two hours.
Some foods, like hard cheeses, uncut vegetables, and breads and tortillas, are safe for longer, since they’re only refrigerated for quality, not safety. See this chart for a full list.
After a Power Shutoff
If your refrigerator's temperature rose above 40 degrees for two hours, discard perishables like meat, poultry and leftovers. But foods such as uncut vegetables and fruits, soy sauce, peanut butter, jelly and other items on this list can still be consumed.
In your freezer, food can be refrozen if it stayed below 40 degrees. See this chart for information on specific foods. “If they still have ice crystals or you see blocks of ice in the packages, you can refreeze them,” said Alonso. “You lose some quality, but it’s not a safety issue.”
Never taste food to see if it’s gone bad! Use a meat thermometer to see whether the internal temperature is below 40 degrees. If not, chuck the food. Again, when in doubt, throw it out.
Remember, some people are especially at risk for foodborne illness. “If you have very young children or pregnant women or cancer survivors, they can’t take risks,” said Alonso. “Their immune systems are not as strong.”
Still have questions? The USDA has food safety experts available at 1-888-MPHotline (1-888-674-6854).