The short answer
Keep the refrigerator and freezer doors closed and record when the outage began. An unopened refrigerator keeps food cold for about four hours. A full unopened freezer holds its temperature for about 48 hours, and a half-full freezer for about 24 hours. After power returns, time, temperature, and ice crystals determine what can be kept.
Start here
- Write down when the power went out.
- Keep the refrigerator and freezer doors closed.
- Put a note on the doors so no one opens them without a reason.
- If the outage reaches four hours, move refrigerated perishables to a cooler with a cold source if you can keep them at 40°F or below.
Before an expected outage
Freeze containers of water, leaving room for the water to expand. They help a freezer stay cold and can later become a cold source for a refrigerator or cooler.
Group frozen food together. Freeze refrigerated food you will not need soon, including leftovers, milk, and fresh meat or poultry. Keep raw meat and poultry where leaking juices cannot reach other food if they begin to thaw.
If you already have a cooler, keep it available. Appliance thermometers are useful because they show whether the refrigerator is at 40°F or below and the freezer is at 0°F or below, but the rest of this procedure still applies without them.
While the power is out
Keep both doors closed as much as possible. Write down when the outage began and share that time with everyone in the home.
An unopened refrigerator keeps food cold for about four hours. A full unopened freezer keeps food cold for about 48 hours. A half-full unopened freezer keeps food cold for about 24 hours.
At four hours, refrigerated perishable food needs another cold source that can keep it at 40°F or below. Use a cooler with ice, frozen water containers, or gel packs if one is available.
After power returns
Do not taste food to decide whether it is safe. Discard refrigerated perishable food, including meat, fish, eggs, milk, cut fruit and vegetables, and leftovers, after four hours without power or another cold source.
Check frozen food package by package. Food may be cooked or refrozen if it still contains ice crystals or measures 40°F or below.
If you cannot determine how warm perishable food became or how long it stayed warm, discard it. Smell, appearance, and taste cannot establish that it is safe.
What not to rely on
- Do not taste food to test it.
- Do not use smell or appearance to clear perishable food as safe.
- Do not treat a coin frozen in a cup as proof that a particular package stayed cold enough. It can show a major thaw, but not the temperature history of the food.
- Do not open the doors repeatedly to check what is inside.
What changes this answer
General guidance becomes a personal decision through these details.
How long it lasts, whether the power returns steadily, and when you first recorded it.
Its starting temperature, how full it is, and how often the door was opened.
Whether you have a cooler, ice, frozen water, gel packs, or appliance thermometers.
Refrigerated perishables, frozen packages, and anything with its own handling instructions.
Where this guidance stops
- This guide does not cover infant formula, medically prescribed food, or medicine that requires refrigeration.
- Food that may have touched floodwater requires separate handling.
- Local public-health instructions and the food manufacturer's directions take precedence when they are more specific.
Sources
Consequential guidance is checked against the linked source material.
- Centers for Disease Control and Prevention. Keep Food Safe After a Disaster or Emergency. Updated November 24, 2025. Checked August 28, 2026.
- U.S. Food and Drug Administration. Food and Water Safety During Power Outages and Floods. Checked August 28, 2026.
- U.S. Department of Agriculture Food Safety and Inspection Service. Freezing and Food Safety. Checked August 28, 2026.
- North Carolina Cooperative Extension. Coin in the Cup: Risky. Food-safety specialists' warning about using the coin method. Checked August 28, 2026.
General information, not advice tailored to you or a guarantee of safety. You are responsible for decisions about your safety. Follow current directions from local authorities. Read the safety disclaimer.