What to do first
- Keep the doors closed
Open the fridge and freezer as little as possible. Both UK food-safety authorities say this helps food remain cold for longer.
- Note the time and temperature
Write down when the power stopped and read a fridge thermometer if you have one. The internal temperature and how often a door was opened matter more than the clock alone.
- Check the food type
Identify food marked keep refrigerated or with a use-by date, cooked leftovers, frozen food and ordinary cupboard food. They do not all have the same storage needs.
- Use current official advice
Check the Food Standards Agency in England, Wales and Northern Ireland, or Food Standards Scotland in Scotland. If you cannot establish that a high-risk chilled food has remained safely stored, do not rely on smell or appearance.
Official time estimates, with limits
- Fridge
- Up to 4 hours cold with the door kept closed; this is an estimate, not a guarantee.
- Full freezer
- Up to 48 hours frozen with the door kept closed; appliance and room conditions can change this.
- Half-full freezer
- About 24 hours frozen with the door kept closed; it may be shorter if frequently opened.
- Usual fridge target
- 5°C or below in normal operation. Official power-cut advice uses under 8°C for temporary chilled storage.
If the fridge warms to 8°C or above
The Food Standards Agency and Food Standards Scotland advise eating food that normally needs refrigeration within four hours once the fridge reaches 8°C or above. The FSA says these foods should be discarded after four hours at that temperature unless power was restored within that period. This includes food with a use-by date, food labelled keep refrigerated and cooked leftovers. Keep the temperature reading and time in mind; do not treat the four-hour fridge estimate as a fresh four hours after a warm reading.
If you have no reliable temperature reading, the elapsed outage time, door openings, room warmth and appliance condition all leave uncertainty. Do not give a food item a safety clearance because it feels cool or smells normal. Food with a use-by date can contain harmful bacteria without obvious signs. For a vulnerable person, take particular care and use food known to have been stored safely.
Both authorities say that suitable chilled food may be stored outdoors when it is cold enough, but it must be kept in a clean, dry, sealed container out of direct sunlight and protected from animals. Outside air is not automatically a safe fridge: check the actual conditions and current official advice.
Use food in a sensible order
- Safely chilled food
Use food that needs refrigeration while it remains safely chilled and within its use-by date or other label instructions.
- Suitable defrosted food
Next consider defrosted frozen food that does not require cooking, only if its storage and handling remain safe. Check the specific food and current official guidance.
- Room-temperature perishables
Use foods such as bread before they deteriorate, following packaging and visible spoilage guidance.
- Cupboard stores
Save sealed tinned, bottled and dried food that is normally stored at room temperature for later. Check the label before eating a tin cold.
Do not decide freezer safety from hours alone
The 48-hour and 24-hour freezer figures assume a closed door and are estimates. They do not certify each item. A freezer's fill level, model, room temperature and door openings change how quickly it warms. If food has defrosted, check the official advice for that food and its label before deciding whether to use or discard it.
Keep raw foods separate from ready-to-eat food and clean hands, utensils and work surfaces during preparation. If cooking is needed, follow the product instructions and ensure food is cooked through. A power cut is not a reason to shorten required cooking.
Give extra attention to higher-risk households
The FSA highlights young children, pregnant women, older people and people with underlying health conditions. For infant formula, follow NHS preparation and sterilisation advice. If boiling water is unavailable, ready-to-feed formula can be an option; check the exact product instructions. Do not substitute cold water for a powdered formula preparation step that requires hot water.
Cooking and the limits of this guide
An electric hob will not work without electricity. If you have another cooking appliance, use it only in the setting and manner allowed by its manufacturer. Do not bring a barbecue or outdoor camping stove indoors; fire-service advice warns of carbon monoxide danger in enclosed spaces. Ready-to-eat cupboard food is the safer fallback when no suitable cooking method is available.
This page cannot inspect your food or know the temperature history of your appliance. The official time figures are planning estimates, not a test of safety. Follow updated local food-safety advice if an incident affects more than the power supply, such as flooding or a water notice.