Essentials
Food safety during a power cut
Keep fridge and freezer doors closed as much as possible during a power cut. Whether food is safe depends on its temperature and how long it has been warm, not just when the electricity failed. A thermometer and a note of the outage time help you make a safer decision.
Published: Updated:
Last checked: 7 November 2026 How we evaluate sources
What to do first
- Note when the power went off, or when you first noticed it. Do not assume an unnoticed overnight cut has just started.
- Keep doors closed. Avoid repeated checks that let cold air escape.
- Use food that does not need refrigeration while you assess the outage.
- Follow any specific food safety advice issued for your area. Keep food away from floodwater or other contamination.
How long food may stay cold
These are estimates for appliances kept closed. Room temperature, the appliance and how full it is affect the time. A freezer time estimate does not prove that every item is still frozen.
| Appliance | Estimated time | What it means |
|---|---|---|
| Fridge | About 4 hours | It may keep food cold for this long with the door closed. Check the time and temperature rules below. |
| Full freezer | About 48 hours | A full freezer retains cold longer than a partly filled one. |
| Half-full freezer | About 24 hours | Plan for a shorter period than a full freezer. |
Use temperature as well as time
Normally keep your fridge at 5°C or below. During an outage, the food safety guidance says chilled food should stay below 8°C. If food that requires refrigeration reaches 8°C or above, it must be eaten within four hours or discarded. Discard it after four hours at that temperature, or if you cannot establish a safe time and temperature history.
This applies to foods such as meat, fish, dairy products, prepared salads and leftovers that require refrigeration. The four-hour limit above 8°C is different from the estimate that a closed fridge may stay cold for four hours. Do not add the two estimates together as a guaranteed safe period.
Keep raw food separate from ready-to-eat food. If frozen food has thawed, follow its label and the Food Standards Agency guidance linked below before cooking or refreezing it. Be especially cautious when preparing food for babies, pregnant people, older people or anyone with reduced immunity.
FSA: current power-cut food safety guidance (opens in a new tab)Food Standards Scotland: power-cut advice (opens in a new tab)
Prepare before the next outage
- Keep a fridge thermometer and know the normal reading.
- Have a small supply of familiar ready-to-eat food and a manual tin opener.
- Plan safe handwashing and washing-up if water is also interrupted.
- If you use infant formula, consider ready-to-feed formula for times when you cannot safely boil water.
- Ask your pharmacist about refrigerated medicines. Food storage time estimates do not apply to medicines.
Common questions
Is food safe if it smells normal?
Smell or appearance cannot establish that chilled food has been stored safely. Use its temperature, time out of safe refrigeration and storage instructions. Discard high-risk food if you cannot establish that it is safe.
Does the fridge's four-hour estimate start again when power returns?
No. Restoring electricity does not erase time that food has already spent too warm. Assess its storage history before keeping or eating it.
Make your next step practical
Keep preparing
Evidence and service information
Sources behind this guidance
We develop our guidance using the sources below. Check the named organisation for current service details, live warnings and local instructions. Sources checked 7 November 2026.
- Food safety in a power cut: advice for consumersFood Standards Agency, England, Wales and Northern Ireland
- Power cuts and food safetyFood Standards Scotland