Prepare information before the lights go out
Keep appliance thermometers in the refrigerator and freezer. Maintain the refrigerator at 40°F (4°C) or below and the freezer at 0°F (-18°C). Know where coolers and frozen gel packs are, and identify a local source of dry or block ice before an emergency. Do not wait for an outage to discover that the thermometer battery is dead or the cooler does not close.
A simple outage sheet should have spaces for power-off time, appliance temperatures, door openings, power-restored time, and food decisions. Time matters because a later cold reading does not reconstruct earlier exposure. If your utility offers outage alerts, use them as supporting evidence rather than the only record.
During the outage, preserve the cold you already have
Keep refrigerator and freezer doors closed as much as possible. FoodSafety.gov states that food remains safe for up to four hours in a refrigerator, about 48 hours in a full freezer, and about 24 hours in a half-full freezer when doors remain closed. These are planning limits, not permission to repeatedly open the door to check individual items.
Group frozen foods only if you can do so quickly and safely; a full, compact freezer retains cold longer than a sparsely filled one. If an outage is expected to last, use coolers, ice, or another reliably cold location according to official instructions. Never place food outdoors where animals, sunlight, changing air temperatures, or contamination make conditions unreliable.
- Write down the outage start time
- Keep refrigerator and freezer doors closed
- Use appliance thermometers
- Preserve product identity and package labels
- Follow local emergency and utility instructions
After four hours, classify food rather than making one rule for everything
FoodSafety.gov advises discarding refrigerated perishable food such as meat, poultry, fish, eggs, and leftovers after four hours without power or another cold source. The official chart distinguishes these foods from items that may be kept, including some whole fruits, hard cheeses, butter, and certain condiments. Use the current chart instead of assuming every refrigerator item has the same risk.
Do not taste food to determine safety. Odor and appearance cannot reliably reveal pathogenic bacteria. When you cannot establish how long a perishable item was above 40°F, the absence of a bad smell is not evidence that resets the timeline.
Frozen food needs temperature or ice-crystal evidence
FDA says frozen food may be safely refrozen or cooked if it still contains ice crystals or is at 40°F (4°C) or below. Refreezing can reduce quality even when the safety condition is met. Inspect packages for leakage and cross-contamination as food thaws, and separate raw products from ready-to-eat food.
If a freezer thermometer reads 40°F or below when power returns, that reading supports refreezing. Without a thermometer, evaluate each package using the official ice-crystal and temperature criteria. Do not infer the condition of food buried in the freezer from one package near the door.
Document disposal and reset the kitchen
Photograph or list discarded items if you may make an insurance claim, but do not delay safe disposal simply to create a perfect inventory. Clean leaked liquids using appropriate food-safety procedures. Replace compromised cardboard or absorbent storage organizers that cannot be cleaned.
After the event, note what information was missing. Replace thermometer batteries, refreeze gel packs, update emergency contacts, and review whether the freezer was too empty to retain cold efficiently. The goal is a better response next time, not retroactive certainty about an undocumented temperature history.
Match the situation before choosing an action
Where simple rules break down
Does opening the refrigerator reset the four-hour window?
No. Opening the door releases cold air and shortens useful cold retention. Record the outage start and keep the door closed.
Can I put refrigerated food outside in winter?
FoodSafety.gov warns that outdoor temperatures vary and food can be exposed to animals or unsanitary conditions. Use controlled cold storage instead.
Is thawed frozen food always unsafe?
Not always. FDA says food that still contains ice crystals or is 40°F or below may be refrozen or cooked, though quality may decline.
Check the underlying guidance
We reviewed the sources below on August 5, 2026. The numbered badges are a page-level navigation index; they do not mean every listed source supports every sentence in the preceding section. Agency pages can change, so use the linked page for current wording and product-specific instructions.
Four-hour refrigerator limit, freezer cold-retention estimates, and keep/discard charts.
Temperature evidence, ice-crystal guidance, and post-outage decisions.
Editorial boundary: This guide organizes published U.S. consumer guidance. It cannot observe your food, verify its temperature history, diagnose illness, or replace instructions for a specific product or emergency.
See outdated guidance or a factual error? Use our correction process.