Keep refrigerator and freezer doors closed. An unopened refrigerator keeps food cold for about four hours. A full freezer holds temperature for about 48 hours; a half-full freezer for about 24 hours.

After four hours without power or another cold source, discard refrigerated perishable food. Never taste food to decide whether it is safe.

A person holding a notepad beside a closed stainless refrigerator.
The most useful tool in an outage kitchen is the note that says when the door last opened.

Quick decision table

Situation Action
Refrigerator without power for 4 hours or less, door kept closed Food should remain safe under federal guidance; verify conditions when possible.
Refrigerator without power for more than 4 hours Discard refrigerated perishables unless they were kept at 40°F or below by another reliable cold source.
Frozen food still has ice crystals or measures 40°F or below It can be refrozen or cooked, although quality may decline.
Perishable food has been above 40°F for 2 hours or more Discard it.
You do not know the time or temperature Use the conservative discard decision; do not taste-test.

The detailed FoodSafety.gov chart lists decisions by food type. When in doubt, discard the food.

The four-hour refrigerator window assumes the door stays closed. Federal guidance says refrigerated perishables should be discarded after four hours without power or another cold source, and food should never be tasted to judge safety. (Source: FoodSafety.gov, Avoid Foodborne Illness During Temporary Power Outages.) After the discard decision is made, cleaning the refrigerator properly is its own job with its own boundaries.

Start a food-safety log

At the beginning of the outage, write down:

  • time utility power failed;
  • refrigerator and freezer temperatures if visible without prolonged opening;
  • whether either door was opened and why;
  • time food entered a cooler and the cooler temperature;
  • when backup power ran and for how long;
  • time utility power returned.

Do not invent a precise temperature history from one reading at the end. If time or temperature is unknown, use the conservative discard decision.

What counts as refrigerated perishable food

After the unsafe time/temperature threshold, discard categories such as:

  • raw or cooked meat, poultry, seafood, and meat substitutes requiring refrigeration;
  • milk, cream, yogurt, soft cheeses, and opened dairy products that require refrigeration;
  • eggs and egg dishes;
  • leftovers, casseroles, soups, pizza, cooked rice, and cooked pasta;
  • cut melons, cut tomatoes, cut leafy greens, and other prepared produce listed in the official chart;
  • refrigerated dough, gravies, sauces, and opened products that the manufacturer says must remain refrigerated.

Some foods may be kept, including certain hard cheeses, butter, uncut produce, breads, and condiments, but the decision depends on the exact product. Use the FoodSafety.gov Food Safety During Power Outage food-by-food chart rather than applying one rule to everything in the refrigerator.

Use freezer evidence correctly

Frozen food that still contains ice crystals or is at 40°F or below may be refrozen or cooked, although quality can decline. A full freezer can maintain a safe temperature for about 48 hours and a half-full freezer for about 24 hours when the door remains closed. (Source: CDC, Keep Food Safe After a Disaster or Emergency.)

The clock is a planning aid, not proof for every item. Door openings, starting temperature, freezer fill, insulation, room temperature, and prior cycling all change the thermal history. Check each package and use a thermometer where possible.

Food that thawed and then refroze when power returned can look frozen later. Ice on the package exterior alone does not establish that the food remained safe.

Before an outage

Place appliance thermometers in both the refrigerator and freezer. Keep the refrigerator at 40°F or below and the freezer at 0°F or below. Freeze containers of water to fill unused freezer space, leaving room for expansion, and know where to buy ice locally.

Group food in the freezer so it stays cold longer, but preserve enough visibility that you do not need to hold the door open. Keep shelf-stable meals that do not require refrigeration or unsafe indoor cooking.

During an outage

  • Put a note on the doors so nobody opens them automatically.
  • Record the outage start time.
  • Do not move food outdoors or into snow. Outdoor temperatures vary, sunlight warms containers, and food can be exposed to contamination.
  • If the outage will exceed four hours, transfer priority refrigerated food to a cooler with ice or frozen packs and keep it at 40°F or below.
  • Keep raw meat separate so leaking packages cannot contaminate ready-to-eat food.

Running a refrigerator from backup power can extend the safe window, but only if the system supports its startup surge and can run on a dependable schedule. Measure temperature rather than assuming that occasional operation is sufficient.

When and how to use a cooler

Move refrigerated perishables to a cooler before the four-hour window closes when the outage is expected to continue and you have enough ice or frozen gel packs to maintain 40°F or below.

  1. Pre-chill the cooler when possible.
  2. Put a thermometer inside.
  3. Separate raw meat and poultry in leak-resistant containers.
  4. Surround food with ice or frozen packs rather than placing a small cold source only on top.
  5. Keep the cooler closed and in the coolest safe location available.
  6. Add ice as it melts and record the temperature.
  7. Drain meltwater only if doing so will not warm or contaminate the food.

Do not place a cooler in a running vehicle, generator area, floodwater, direct sun, or a location exposed to animals. Dry ice requires ventilation and handling precautions; follow supplier and public-health instructions and never touch it with bare skin.

Special cases

Infant formula and human milk

Do not apply a generic leftover rule to infant feeding. Follow current CDC guidance, product labeling, and the child’s clinician for prepared formula, opened ready-to-feed formula, and expressed human milk. Use safe water when preparing powdered formula.

Refrigerated medication

Food rules do not determine medication safety. Check the label and contact the pharmacist, clinician, or manufacturer. The CDC advises replacing refrigerated drugs after an extended outage unless product-specific instructions say otherwise, with urgent continuity decisions handled through the care plan. (Source: CDC, What to Do to Protect Yourself During a Power Outage.)

Floodwater or stormwater contact

Food exposed to floodwater can be contaminated independently of temperature. Discard food in containers that cannot be safely cleaned and sanitized under official guidance. Do not consume food from swollen, leaking, punctured, deeply rusted, or badly damaged cans.

Restaurant, delivery, and shared-building food

Do not assume a restaurant, community refrigerator, or delivered meal maintained temperature during the same regional outage. Ask how cold holding was maintained and follow public-health notices.

When power returns

Check the thermometers before moving or opening more food. Evaluate each category using the official chart. Appearance, smell, and a cold exterior are not reliable evidence that harmful bacteria did not grow.

Clean and sanitize surfaces exposed to leaks. Document discarded food before disposal if your insurance or local assistance program may require evidence.

Restore the refrigerator to 40°F or below and the freezer to 0°F or below. Do not immediately pack warm replacement groceries into an appliance that has not cooled. Recharge ice packs, wash coolers, replace thermometer batteries if needed, and note which foods caused the most uncertainty.

Build a lower-loss food plan

  • Keep appliance thermometers visible.
  • Freeze water containers and gel packs before forecast events.
  • Store shelf-stable meals that require little water and no indoor combustion.
  • Divide expensive frozen food across smaller labeled zones so inventory can be checked quickly.
  • Keep raw foods contained below ready-to-eat foods.
  • Know where ice is sold, but do not depend on a store that may share the outage.
  • Maintain a manual can opener and safe cold-weather cooking plan.
  • Photograph refrigerator/freezer contents before a forecast storm for inventory and insurance documentation.

For energy planning, see Backup Power for Home and the power station runtime calculator. For the complete household response, return to Power Outage Preparedness.

Use the cooler and ice guide for controlled cold storage, and record actual times and temperatures in the food outage timeline log. Neither route overrides the authority-led discard rules on this page.

Sources reviewed

  • FoodSafety.gov: Avoid Foodborne Illness During Temporary Power Outages
  • FoodSafety.gov: Food Safety During Power Outage chart

Sources reviewed July 13, 2026. This critical-risk draft remains unpublished until expert review is recorded.