Practical AtlasIndependent referenceHow long food stays safe
The two numbers to remember are 4 hours and 48 hours.
USDA says a refrigerator keeps food safe for up to 4 hours without power if the door stays closed. A full freezer holds its temperature for about 48 hours, or about 24 hours if it is half full, again with the door closed. Every opening shortens both.
During the outage
Keep the doors shut and move food only when you have to.
If the power will be off longer than 4 hours, USDA suggests moving refrigerated food into a cooler with ice or frozen gel packs, keeping it at 40°F or below and adding ice as it melts. For a long outage, dry ice or block ice helps: USDA says 50 pounds of dry ice should hold an 18-cubic-foot freezer for 2 days. Never touch dry ice with bare hands.
What to keep and what to throw out
The line is food held above 40°F for more than 2 hours.
USDA says to discard refrigerated perishables — meat, poultry, fish, eggs, and leftovers — after 4 hours without power. For other items exposed to 40°F or above for more than 2 hours, FoodSafety.gov gives an item-by-item chart:
| Usually discard | Usually safe to keep |
|---|---|
| Raw or cooked meat, poultry, seafood, lunch meat | Hard cheeses such as cheddar, Swiss, and Parmesan |
| Milk, cream, yogurt, soft and shredded cheeses | Butter and margarine |
| Eggs and egg dishes | Uncut fresh fruit and vegetables |
| Cooked pasta, rice, and potatoes | Bread, rolls, and cakes without cream fillings |
| Cut fruit and vegetables, pre-cut greens | Peanut butter, jelly, mustard, ketchup, pickles |
| Opened creamy dressings, opened spaghetti sauce | Opened vinegar-based dressings |
Never taste food to decide whether it is safe. The federal rule is “when in doubt, throw it out.”
Refreezing thawed food
Ice crystals, or 40°F and below, decide it.
Frozen food that still contains ice crystals, or has stayed at refrigerator temperature of 40°F or below, may be safely refrozen, though its quality may suffer. FoodSafety.gov lists exceptions: ice cream and frozen yogurt should be discarded once thawed, and most thawed foods held above 40°F for more than 2 hours should go.
Before the next outage
Five minutes of preparation changes the outcome.
- Keep an appliance thermometer in both the refrigerator and the freezer: the fridge should be at 40°F or below, the freezer at 0°F or below. After the power returns, the thermometers tell you what happened while you were not watching.
- Keep the freezer full — frozen jugs of water fill empty space — and group foods together so they stay cold longer.
- Have a cooler and frozen gel packs ready, and know where to buy dry ice or block ice.
- If a longer outage is expected, see the guides to generator safety and to a refrigerator that is not cooling.
QUESTIONS THIS ANSWERS
Questions this answers
How long does food last in the fridge without power?
USDA says a refrigerator keeps food safe for up to 4 hours without power if the door stays closed. A full freezer holds its temperature for about 48 hours, or about 24 hours if it is half full.
What food should I throw out after a power outage?
USDA says to discard refrigerated perishables such as meat, poultry, fish, eggs, and leftovers after 4 hours without power, and generally any perishable food held above 40°F for more than 2 hours. Never taste food to decide whether it is safe.
Can I refreeze food that thawed during an outage?
Frozen food that still contains ice crystals, or has stayed at 40°F or below, may be safely refrozen, though its quality may suffer. FoodSafety.gov says ice cream and frozen yogurt should be discarded once thawed.
Found something wrong? Report an error (reference HS-0050) or read the corrections policy.
2 SOURCESEvidence ledger
Sources
- 01Food Safety During Power Outage ↗
FoodSafety.gov · accessed Sep 29, 2026
- 02Keep Your Food Safe During Emergencies: Power Outages, Floods & Fires ↗
USDA Food Safety and Inspection Service · accessed Sep 29, 2026