Power Outages
Food safety in a power outage: a keep-or-toss chart for the fridge and freezer
An unopened refrigerator keeps food cold for about 4 hours, a full freezer for about 48. Here is the 40 °F line, an item-by-item keep-or-toss chart and a log you tape to the door, so you can sort the kitchen in minutes instead of guessing.
It is the second morning without power. You have opened the fridge twice, the kids are asking for lunch, and you are holding a carton of milk in one hand and a package of chicken in the other. Last time, after a 36-hour outage, you threw out about $120 of food because you could not be sure, and you never found out whether you had to.
Here is the short answer. An unopened refrigerator keeps food cold for about 4 hours, and a full freezer for about 48 hours (about 24 if it is half full), with the doors shut (FDA). After that, one number decides: 40 °F (4 °C). Perishable food that rose above it for more than 2 hours is discarded (Penn State Extension). The chart below sorts the fridge item by item, so the decision takes minutes instead of a guessing game.
How this page decides, and why you can check it
Every number here comes from the FDA, Penn State Extension or the National Center for Home Food Preservation pages in the Sources section. Each claim names its source, and the links open the original page. This site has no staff of experts, and no food-safety professional reviews these guides; pages are written with AI-assisted drafting and checked against those sources, as explained on the how we write page. Canning guidance on this site follows USDA and National Center for Home Food Preservation tested methods only. There are no product picks, ratings or prices here, and a thermometer from any store does the same job.
Key takeaways
- An unopened fridge keeps food cold about 4 hours; a full freezer about 48 hours, a half-full one about 24 (FDA).
- 40 °F (4 °C) is the line. Perishables above it for more than 2 hours are discarded (Penn State Extension).
- If the power is off more than 2 hours, start checking the fridge temperature about every hour (Penn State Extension).
- When the fridge reaches 40 °F, put block ice in a container inside, or move perishables to a cooler with ice (Penn State Extension).
- Hard and processed cheese, grated Parmesan and Romano, margarine and butter are listed as safe even above 40 °F for more than 2 hours (Penn State Extension).
- Food is safe indefinitely while it is still frozen. Once it thaws, treat it as refrigerator food (NCHFP).
- Never taste food to judge it. Anything with an unusual odor, color or texture is discarded (Penn State Extension).
The power just went out: do this now
- Write down the hour the power went off. Every limit on this page counts from that minute.
- Shut both doors and leave them shut. For an outage of only a few hours, Penn State Extension says to do nothing and open the doors as little as possible.
- Move the appliance thermometer to the front of the fridge, close to the door opening, so a crack of the door is enough to read it (Penn State Extension).
- If the outage will run past 4 hours, get coolers, ice cubes and frozen gel packs ready now (FDA).
Things this guide mentions
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How long will food last in a power outage?
Two numbers do most of the work: about 4 hours for the refrigerator and about 48 hours for a full freezer, both with the door kept closed. Everything else is a version of those two.
| Unit | Safe for about | What that means for you |
|---|---|---|
| Refrigerator, unopened | 4 hours | After 2 hours, check the temperature hourly; at 40 °F, add block ice or move perishables to a cooler (Penn State Extension) |
| Full freezer | 48 hours | Still-frozen food is safe; thawed food gets the fridge rule (NCHFP) |
| Half-full freezer | 24 hours | The same check, just sooner |
| Cooler with ice | Use it when the outage will pass 4 hours | Move perishables before the fridge warms, not after (FDA) |
These are estimates, not stopwatch readings. How often the door opens, how full the unit is and how warm the room is all change the real time. That is why Penn State Extension suggests monitoring rather than assuming: once the power has been off more than 2 hours, check the temperature about once an hour and note it down.
If you are only a few hours in and the doors have stayed shut, nothing has crossed a limit yet. Do not start hauling food to the garage. Use the time to eat from the pantry and to line up ice or coolers. The fridge food chart goes deeper on the refrigerator, and the freezer keep-or-toss guide covers frozen food.
Power outage food safety: the 40 °F line
40 °F to 140 °F is what the National Center for Home Food Preservation calls the danger zone, where bacteria multiply rapidly. Food is safe indefinitely while frozen, but as soon as it begins to defrost and warms above 40 °F, bacteria that were present before freezing can start to multiply (NCHFP). That is the logic of this page in two sentences.
Before an outage, the FDA suggests setting the freezer to 0 °F or below and the refrigerator to 40 °F or below, with an appliance thermometer in each. After the power goes, Penn State Extension's rule is specific: if the refrigerator rises above 40 °F for more than 2 hours, the perishable foods on its list must be discarded.
You cannot use taste or smell as a test. Penn State Extension says any food with an unusual odor, color or texture should be discarded, and you should never taste foods to determine their safety. A normal-smelling container of yogurt proves nothing about its temperature. If you do not own a thermometer, plan on the conservative side: if you cannot show that the food stayed cold, it goes.
Food in the fridge after a power outage: keep or toss, item by item
The right column follows Penn State Extension's discard list for perishables that have risen above 40 °F for more than 2 hours. Anything not on the list is judged by the 40 °F rule itself: at or below 40 °F, keep it.
| Food | Stayed at 40 °F or below | Above 40 °F for more than 2 hours |
|---|---|---|
| Meat, poultry, seafood, raw or cooked | Keep | Throw out |
| Cold cuts, hot dogs | Keep | Throw out |
| Casseroles, pizza, soups and stews with meat or dairy | Keep | Throw out |
| Custards, pudding | Keep | Throw out |
| Cream, sour cream | Keep | Throw out |
| Soft cheeses, shredded cheeses, low-fat cheeses | Keep | Throw out |
| Milk, yogurt | Keep | Throw out |
| Eggs | Keep | Throw out |
| Creamy salad dressings, fish sauce, hoisin sauce, opened spaghetti sauce | Keep | Throw out |
| Cookie dough, refrigerator biscuits or rolls | Keep | Throw out |
| Cooked pasta, rice, pasta salads | Keep | Throw out |
| Cut fresh fruit, greens, cooked vegetables, opened vegetable juice | Keep | Throw out |
| Baked or mashed potatoes, potato salad | Keep | Throw out |
| Hard and processed cheeses properly wrapped, grated Parmesan and Romano, margarine or butter | Keep | Keep — listed as safe even above 40 °F for more than 2 hours |
| Anything with an unusual odor, color or texture | Throw out | Throw out |
Freezer food follows a different test. Food that is still frozen can stay; the NCHFP says food is safe indefinitely while frozen. Once a package has thawed, it is refrigerator food: give it the 2-hour rule above and the chart you just read. Do not throw out a still-frozen package just because the power went off.
Watch for: the taste test
Never taste food to decide whether it is safe, and never decide by smell alone. Penn State Extension's rule is to discard anything with an unusual odor, color or texture, and it says plainly that you should never taste foods to determine their safety. When you cannot tell, the food goes.
The sort, step by step
Write down the time the power went off
Note the hour, and note anyone opening the door after that. Both the 4-hour refrigerator figure and the 48-hour freezer figure assume the door stays shut.
Done when: the start time is written on a note on the fridge door.
Keep the doors shut
Penn State Extension says that for an outage of only a few hours you should do nothing and open the doors as little as possible. The FDA says the same: keep the refrigerator and freezer doors closed to hold the cold in.
Done when: nobody is opening the fridge just to check.
Put the thermometer where you can read it through a crack
Keep the appliance thermometer close to the door opening. Penn State Extension recommends starting checks once the power has been off for more than 2 hours, then checking about every hour.
Done when: you have a first reading written down.
Act the moment the fridge reads 40 °F
This is the trigger, not the finish line. Penn State Extension's advice at that point is to place block ice in a container inside the refrigerator, and to consider moving perishable items into a cooler surrounded by ice or ice packs.
Done when: ice is in, or the perishables are in a cooler.
Sort with the chart, not your nose
Make three piles: keep, cook now, and out. Use the chart above for refrigerated items and the still-frozen test for frozen ones. Anything with an unusual odor, color or texture goes straight into the out pile without a taste test (Penn State Extension).
Done when: every container in the fridge has been assigned to a pile.
Cook the cook-now pile and clean up
Food that stayed cold but is now thawed is best cooked and eaten rather than left to sit. Once the out pile is bagged, wipe the shelves and door bins before the power returns and the rest of the shopping goes back in.
Done when: the fridge is clean, the trash is out, and the log is complete.
The decision log you tape to the fridge door
The reason an outage feels unmanageable is that all of this lives in your head at 6 a.m. with two kids asking for breakfast. Put it on paper on the outside of the door instead. A strip of paper and a pen are enough; draw these headings before the next outage.
| Column | What goes in it |
|---|---|
| Power out | The exact hour, and the hour it comes back |
| Time checked | Each reading, about hourly once you pass 2 hours (Penn State Extension) |
| Fridge / freezer temp | Both readings, in °F |
| Action taken | Ice in, cooler out, doors taped shut |
| Thrown out | What, and roughly what it cost — useful for a claim and for next time |
A $120 fridge, sorted in 20 minutes
A household of four loses power at 6 p.m. on a Friday during an ice storm. Someone writes the time on a note and tapes it to the fridge door. Nobody opens the fridge that evening. At 8 a.m. Saturday, about 14 hours in, they open the door a crack and read the fridge thermometer: 44 °F. That is above the 40 °F line, so the clock is running.
They move the milk, raw chicken, deli meat, yogurt and two containers of leftovers into a cooler with ice packs — the foods on Penn State Extension's discard list — and leave the hard cheese, butter, Parmesan and a jar of jam in place, since those are listed as safe even above 40 °F for more than 2 hours. The opened spaghetti sauce in the door goes in the trash, along with a custard nobody finished. A tub of sour cream with an off smell follows it, without anyone tasting it.
The freezer is three-quarters full. At 30 hours they check: the chicken breasts are still hard, so the NCHFP rule says still-frozen food is safe, and it goes back in when the power returns at 6 a.m. Sunday, 36 hours after it went out. The total thrown out comes to roughly $12 instead of $120, and every item that went out went for a reason they could point to in a source.
The difference between the two outages is not equipment. It is a thermometer in the fridge, a note on the door and a chart that answered the question in minutes.
Keep it cold longer, before and during the outage
- Two appliance thermometers, one per unit. The FDA suggests one in each, with the freezer at 0 °F or below and the fridge at 40 °F or below before an outage starts.
- Freeze water containers for ice. The FDA suggests freezing containers of water to keep food cold in the fridge, freezer or coolers, and notes that the melting ice is drinking water if your supply is out.
- Group food together in the freezer. The FDA lists this as a way to help food stay cold longer.
- Freeze leftovers, milk and meat you will not use soon. The FDA suggests this so they hold a safe temperature longer.
- Have coolers, ice cubes and gel packs ready. The FDA suggests coolers for outages longer than 4 hours, plus ice cubes and frozen gel packs made ahead.
- Know where to buy block ice or dry ice. The FDA gives one planning figure: 50 pounds of dry ice should keep an 18-cubic-foot, fully stocked freezer cold for two days. Ask the seller for safe-handling instructions when you buy it.
If you need them: appliance thermometers (Amazon, affiliate link) opens in a new tab for the fridge and freezer, and digital food thermometers (Amazon, affiliate link) opens in a new tab for checking individual packages once they thaw. A thermometer from any store will do the same job.
Watch for: generators and carbon monoxide
If you run a generator to power the fridge, never use it indoors, in a garage, in a basement or in any partly enclosed space, and do not count on open doors or windows to clear the exhaust (American Red Cross). Ready.gov says to keep it at least 20 feet from doors, windows and vents and to have battery-powered carbon monoxide alarms. Never plug a generator into a wall outlet; a permanent connection needs a transfer switch installed by a licensed electrician. If a CO alarm sounds, get everyone outside and call 911.
Troubleshooting
- If you do not know when the power went out
- Use the earliest time you can confirm, and treat the food as if the clock started then. If you genuinely cannot tell and have no temperature reading, use the 2-hour rule as your default and discard the perishables on the list.
- If the fridge was opened several times
- The 4-hour figure assumes the door stays closed (FDA). Each opening costs cold air, so shorten your own timeline and rely on the thermometer readings rather than the clock.
- If the fridge reads just under 40 °F but the outage is not over
- You are still inside the line, so nothing has to be thrown out yet. Add block ice in a container now, or move perishables to a cooler with ice, so the next reading does not cross 40 °F (Penn State Extension).
- If the fridge reads 40 °F or above and you do not know for how long
- Assume it has been above the line and start counting from the moment you found it. Perishables above 40 °F for more than 2 hours are discarded (Penn State Extension).
- If a package looks and smells completely normal
- That is not evidence. Penn State Extension says never to taste food to determine its safety, and appearance is not a thermometer. Use the reading and the chart.
- If the power comes back and the fridge is warm
- Clean the shelves and bins, then restock. Do not put thawed refrigerator food that ran above 40 °F for more than 2 hours back in the cold; the refreezing thawed meat guide walks through the freezer side of that decision.
When to get help
Call for help if
- A carbon monoxide alarm sounds, or anyone feels dizzy, sick or sleepy near a running generator: get everyone outside, then call 911.
- Anyone in the household feels unwell after eating food you were unsure about: contact a health care provider. This site does not give medical advice.
- You have a food safety question the chart does not answer, especially about a food that is not on the list: your local Cooperative Extension office can talk it through with you.
Who to ask. In an emergency, call 911. If a carbon monoxide alarm sounds or anyone feels dizzy, sick or confused, get everyone outside into fresh air first, then call 911. Report outages and downed power lines to your utility. For local hazards, shelters and alerts, contact your city or county emergency management office (start at Ready.gov).
Frequently asked questions
How long will food last in a power outage?
With the doors kept shut, an unopened refrigerator holds food cold for about 4 hours, a full freezer for about 48 hours and a half-full freezer for about 24 (FDA). After that the temperature decides: perishables that rose above 40 °F for more than 2 hours are discarded (Penn State Extension). Food that is still frozen is safe, the NCHFP says.
Is the food in my refrigerator safe after a power outage?
It is safe if it stayed at 40 °F or below. Check with an appliance thermometer. The moment the fridge reaches 40 °F, add block ice in a container or move perishables to a cooler with ice, and remember that perishables above 40 °F for more than 2 hours are discarded (Penn State Extension). Meat, milk, eggs, soft cheese and leftovers are on that discard list; hard cheese, butter and grated Parmesan are not.
Can I refreeze food that thawed during the outage?
If it is still frozen, it is safe to keep, because the NCHFP says food is safe indefinitely while frozen. Once a package has fully thawed, treat it as refrigerator food: 40 °F or below is the line, and above 40 °F for more than 2 hours means discard (Penn State Extension). The NCHFP also warns never to thaw food at room temperature or in warm water.
What if the power was only out for two hours?
Then you are well inside the 4-hour figure for an unopened refrigerator (FDA), and nothing in the fridge has crossed the 2-hour above-40 °F limit. Penn State Extension's advice for a short outage is simply to do nothing and open the doors as little as possible. Close it, wait, and check the temperature if the outage runs longer.
Should I just throw everything out to be safe?
No. Penn State Extension's discard list is specific: meat, poultry, seafood, milk, yogurt, eggs, soft and shredded cheeses, cooked pasta and rice, cut fruit and cooked vegetables, and similar perishables. It also names foods that are safe even above 40 °F for more than 2 hours, including properly wrapped hard and processed cheeses, grated Parmesan and Romano, margarine and butter. Sorting saves money without taking a risk.
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Sources
- Food and Water Safety During Power Outages and Floods, U.S. Food and Drug Administration (accessed November 1, 2026).
- Keeping Food Safe When the Power Goes Out!, Penn State Extension (accessed November 1, 2026).
- Thawing and Preparing Foods for Serving, National Center for Home Food Preservation (accessed November 1, 2026).
- Power Outages, Ready.gov, FEMA (accessed November 1, 2026).
- Generator Safety, American Red Cross (accessed November 1, 2026).
Ready for the next outage
Before, during and after an outage, in order: food safety, light, water, staying warm or cool, and generator safety.