About 4 hours when unopened. After that, perishables need a verified cold source at 40°F or below.
Power outage food safety
How long is food safe in the refrigerator or freezer when the power goes out?
An unopened refrigerator keeps food cold for about 4 hours. A closed, full freezer holds a safe temperature for approximately 48 hours, or 24 hours when half full. What happens next depends on measured temperature, time, and the type of food.
By Self Reliance Daily ·
The numbers to know
Refrigerator
Full freezer
Half-full freezer
Use 4 hours for the refrigerator and 48 or 24 hours for the freezer.
The Centers for Disease Control and Prevention, the U.S. Food and Drug Administration, and the U.S. Department of Agriculture give the same basic holding estimates when the appliance doors stay closed. A refrigerator keeps food cold for about 4 hours. A full freezer holds temperature for approximately 48 hours, while a half-full freezer holds it for approximately 24 hours.
Those windows assume the appliances started at safe temperatures. The refrigerator should normally be at 40°F or below. The freezer should normally be at 0°F or below. They also assume you keep the doors shut. Every unnecessary opening lets cold air out and makes the estimate less useful.
If the refrigerator has been without power for 4 hours and you have no other cold source, CDC guidance says to discard refrigerated perishable food such as meat, fish, eggs, milk, cut fruit and vegetables, and leftovers. If a cooler and ice are available, move those foods at the 4-hour mark and use enough ice or frozen gel packs to keep them at 40°F or below.
Approximately 48 hours when the door remains closed and the freezer began at a safe temperature.
Approximately 24 hours when the door remains closed. A small freezer compartment may not hold food frozen this long.
Treat 4, 24, and 48 hours as conditional planning windows, not guarantees that override a thermometer.
Do not mix the clocks
The 4-hour outage rule and the above-40°F 2-hour rule answer different questions.
This distinction prevents the two most common errors: throwing away every cold item too early or keeping perishable food too long.
Four hours without refrigerator power
The 4-hour rule is a simple decision point when the refrigerator stays closed but you do not have a dependable record of the food temperature.
Use it when
- the refrigerator lost power
- there is no added ice or other cold source
- you cannot prove the food stayed at 40°F or below
Action
- keep the door closed
- move perishables to a cooler by 4 hours if you can hold 40°F or below
- otherwise discard refrigerated perishables after 4 hours
More than 2 hours above 40°F
The current FoodSafety.gov outage chart says many perishable foods should be discarded after they have been above 40°F for more than 2 hours.
Use it when
- you have reliable thermometer readings
- you know how long the food was above 40°F
- you are evaluating the specific food category in the chart
Action
- discard affected meat, dairy, eggs, leftovers and other listed perishables
- check the chart because some shelf-stable foods have different guidance
- do not assume cooking makes time-abused food safe
Why 0°F and 40°F both appear
Zero degrees is the normal target for a working freezer. Forty degrees is the post-outage decision threshold used to assess thawed frozen food.
Before an outage
- refrigerator at 40°F or below
- freezer at 0°F or below
- use an appliance thermometer in each compartment
After an outage
- ice crystals still present: food may be refrozen or cooked
- food at 40°F or below: it may be refrozen or cooked
- quality can decline after thawing and refreezing
Before an outage
A thermometer and a cold-source plan remove most of the guesswork.
Keep one appliance thermometer in the refrigerator and one in the freezer. An appliance thermometer reports the compartment temperature even when the appliance display is dark. A separate food thermometer helps check an individual package when the power returns.
The FDA recommends freezing containers of water, making ice, and freezing gel packs in advance. It also recommends freezing refrigerated items you will not need immediately, including leftovers, milk, fresh meat, and poultry. Grouping food in the freezer helps it retain cold longer.
Keep a large insulated cooler ready. It is only useful for perishable food when you have enough ice or frozen gel packs to hold 40°F or below. Plan where you can obtain block ice or dry ice before a long outage. Pair that cold-storage plan with familiar shelf-stable meals from the food storage basics guide so you do not need to keep opening the refrigerator.
While the power is out
Close the doors, note the time, and protect the cold you already have.
The safest first action is also the simplest: leave both appliance doors closed.
First 4 hours
Do this:- record when the outage started
- leave refrigerator and freezer doors shut
- use shelf-stable food instead of opening the refrigerator
- check utility updates without repeatedly inspecting food
Do not: treat the appliance holding estimates as exact if doors were opened or the appliance was not cold beforehand.
At the refrigerator limit
Do this:- move refrigerated perishables to a cooler at about 4 hours
- add enough ice or frozen gel packs to hold 40°F or below
- keep checking temperature and add ice as it melts
- keep raw meat separated so juices cannot contaminate other food
Do not: assume that simply putting food in a cooler stops the clock. Temperature is what matters.
For a longer freezer outage
Know this:- food near the front, door, or in thin packages thaws faster
- a refrigerator freezer compartment may not match a separate freezer
- block ice or dry ice can extend cold storage
- a full closed freezer generally lasts longer than a half-full one
Do not: put food outdoors or in snow. USDA warns that temperatures vary and food can be exposed to sunlight, animals, and unsanitary conditions.
Dry ice needs protective handling and ventilation.
The USDA estimates that 50 pounds of dry ice can hold an 18-cubic-foot, fully stocked freezer cold for about two days. This is an estimate, not a promise for every appliance. USDA says not to touch dry ice with bare hands or place it directly against food. A CDC dry ice safety sheet advises insulated gloves, a well-ventilated area, and a container that allows gas to escape. Never seal dry ice in an airtight container.
When power returns
Check time, temperature, ice crystals, and contamination before deciding.
Start with the appliance thermometers. If the freezer thermometer reads 40°F or below, FDA and USDA guidance says the food is safe to refreeze. If there was no freezer thermometer, check each package. Food that still contains ice crystals or measures 40°F or below may be cooked or refrozen, although its texture and flavor may be worse.
For the refrigerator, use the conservative outage rule when there is no dependable temperature record. After 4 hours without power or another cold source, discard perishable food. If food was transferred to a monitored cooler, keep it only while the cooler remains at 40°F or below. If you know a food was above 40°F, use the FoodSafety.gov item chart and its exposure limits instead of guessing from smell.
Never taste food to test it. Unsafe food can look and smell normal. Also discard food that was contaminated by leaking raw meat, poultry, or seafood juices. The FDA warns that perishable food held at unsafe temperatures may cause illness even after it is thoroughly cooked. Cooking is not a reset button for bad time-and-temperature control.
No temperature record after a long outage means less certainty, not permission to stretch the limit.
Keep, refreeze, or discard
Evaluate the food category, not just the appliance it came from.
The official chart contains exceptions. These examples cover common foods, but the complete FoodSafety.gov power-outage chart should decide an item that is not listed here.
Discard after the applicable limit
Discard raw or cooked meat, poultry, fish, seafood, eggs, milk, yogurt, soft cheese, shredded cheese, leftovers, soups, stews, casseroles, pizza, cut fruit, cut vegetables, cooked rice, cooked pasta, cooked potatoes, creamy dressings, and cream- or custard-filled pastries when they exceed the official time and temperature limit.
Some foods may be kept
The chart lists hard and processed cheeses, butter, margarine, whole uncut fruit and vegetables, bread without custard filling, fruit pies, peanut butter, jelly, mustard, ketchup, relish, pickles, olives, and vinegar-based dressings as foods that can be kept after more than 2 hours above 40°F. Check for the exact category before keeping it.
Refreeze or cook at 40°F or below
Frozen meat, poultry, seafood, soups, milk, egg products, soft cheese, fruit, vegetables, and many prepared foods may be refrozen when ice crystals remain or the food is 40°F or below. Quality may decline. FoodSafety.gov separately lists ice cream and frozen yogurt as discard, even in the still-cold column.
Most perishables must go
Discard thawed meat, poultry, seafood, milk, egg products, soft cheese, shredded cheese, cheesecake, casseroles, and frozen meals after more than 2 hours above 40°F. The chart gives frozen vegetables and vegetable juice a 6-hour limit above 40°F and allows some foods, including hard cheese, plain bread, flour, cornmeal, nuts, and some fruit products, to be refrozen.
Special case: the official chart says opened mayonnaise, tartar sauce, and horseradish should be discarded when held above 50°F for more than 8 hours.
Practical checklist
Follow the same order before, during, and after every outage.
A short repeatable process is safer than trying to remember every food category under stress.
Prepare the cold chain
Checklist
- put an appliance thermometer in each compartment
- verify 40°F or below in the refrigerator
- verify 0°F or below in the freezer
- freeze water containers and gel packs
- keep a cooler and food thermometer ready
- store familiar no-cook food
Protect the remaining cold
Checklist
- note the outage start time
- keep refrigerator and freezer doors closed
- use pantry food first
- move refrigerator perishables to a cooler by 4 hours
- hold cooler food at 40°F or below
- handle dry ice safely if it is used
Make item-by-item decisions
Checklist
- read the appliance thermometers
- check frozen packages for ice crystals
- measure individual food when needed
- use the official food chart
- discard food contaminated by raw juices
- never taste food to judge safety
Common mistakes
Smell, snow, and cooking cannot replace temperature control.
Do not open the doors repeatedly to see whether food still feels cold. Do not place food outside because winter air feels cold. Outdoor temperatures change, sunlight can warm frozen food, and animals or dirty surfaces can contaminate packages.
Do not assume every thawed item must be discarded. Ice crystals or a measured temperature of 40°F or below can make many frozen foods eligible for cooking or refreezing. The reverse mistake is just as serious: food that smells normal is not automatically safe, and reheating cannot reliably rescue food held too warm for too long.
Do not turn the freezer estimates into guarantees. A half-empty freezer, an internal refrigerator freezer compartment, thin packages near the door, and repeated opening all reduce confidence in a 24- or 48-hour estimate. Use the thermometer and official food-category chart whenever possible.
Simple gear to compare
Start with temperature information and a verified cold source.
These are category searches, not ranked product recommendations. Choose equipment that fits your appliance, household, and storage space, then verify food temperature during use.
Affiliate disclosure: As an Amazon Associate, Self Reliance Daily earns from qualifying purchases. The two category links below are affiliate links. Availability, prices, specifications and listing details can change, so check the current Amazon page before buying.
Refrigerator and freezer appliance thermometers
Useful for: showing compartment temperature before, during, and after an outage when the appliance display may be off.
Check before buying:- a readable Fahrenheit scale that includes 0°F and 40°F
- whether it hangs, stands, or attaches securely
- whether you need one unit for each compartment
- manufacturer instructions for placement and cleaning
Insulated coolers and reusable ice packs
Useful for: moving refrigerated perishables when an outage approaches 4 hours and the cooler can be held at 40°F or below.
Check before buying:- interior space for your priority foods and cold sources
- a lid that closes securely
- cleaning and drainage instructions
- enough frozen packs or ice to maintain 40°F or below
No cooler or ice pack has a universal safe holding time. Use enough cold source to keep food at 40°F or below and verify with a thermometer.
When the history is unknown, do not taste your way to an answer.
Use the known outage time, measured temperature, visible ice crystals, and the official item chart. If those facts cannot establish that a perishable food stayed within the guidance, discard it. For wider outage planning, see power basics and the small-apartment emergency kit.
Official sources used for this guide
This page uses current U.S. government consumer guidance. Check local public-health notices during a specific disaster.
- CDC: Keep Food Safe After a Disaster or Emergency
- FoodSafety.gov: Food Safety During Power Outage
- USDA FSIS: Keep Your Food Safe During Emergencies
- USDA FSIS: Keeping Food Safe During an Emergency
- USDA FSIS: Freezing and Food Safety
- FDA: Food and Water Safety During Power Outages and Floods
- Ready.gov: Power Outage Hazard Information Sheet
- CDC: Dry Ice Safety
- CDC: People at Increased Risk for Food Poisoning
Build the rest of the outage plan.
Cold-food safety works best with shelf-stable meals, a realistic backup-power plan, and equipment sized for your home.