The short answer: about 4 hours in a closed fridge, about 24 hours in a half-full freezer and about 48 in a full one. After that, perishables go in the bin. Here are the details.
The times that matter
| Where | Stays cold if unopened |
|---|---|
| Fridge | about 4 hours |
| Half-full freezer | about 24 hours |
| Full freezer | about 48 hours |
The key is not opening the door. Every time you open it, the clock runs faster.
What to throw away if the fridge has been off for more than 4 hours
- Meat, chicken and fish, raw or cooked.
- Milk, cream, yoghurts and fresh or soft cheeses.
- Eggs and egg dishes.
- Leftovers of cooked food.
- Opened sliced cured meats and homemade sauces.
What usually keeps
- Hard, cured cheeses.
- Butter and margarine.
- Whole, uncut fruit and vegetables.
- Bread and pastries.
- Ketchup, mustard, jam and pickles.
Golden rule: if in doubt, throw it out. Smell and appearance won’t tell you whether food is safe.
The freezer
If food still has ice crystals or is as cold as if it had just come out of the fridge, it can be refrozen, although it may lose some quality. If it’s at room temperature, treat it like the fridge food.
How to buy time
- Keep the freezer full: it lasts twice as long. A few frozen water bottles fill the gaps and can be drunk later.
- A fridge thermometer tells you the truth: above 4 °C, the clock is ticking.
- Group frozen food together: it stays cold longer.
- Eat the fridge food first, then the freezer, and the pantry last.
Better not to depend on the fridge
The safest option is a pantry that needs no cooling: tinned food, jarred pulses, ready meals in tins, UHT milk. You’ll find the full list and ready-calculated kits in what food to buy for a blackout.
Sources: USDA Food Safety and Inspection Service, “Keep Your Food Safe During Emergencies”.