A long outage can easily cost a family a few hundred dollars in spoiled groceries. Worse, people get sick from food that “seemed fine.” This guide covers how to protect what’s in the fridge and how to tell when something isn’t safe anymore.

Two numbers worth remembering

The USDA’s guidance is simple:

  • A closed refrigerator keeps food safe for about 4 hours.
  • A closed freezer holds for about 48 hours if it’s full, or 24 hours if it’s half full.

For the fridge, the danger line is 40°F. Perishable food that’s been above that for more than two hours should go in the trash.

Before the outage

  1. Put a thermometer in both the fridge and the freezer. Afterwards, it’s the only way to know for sure.
  2. Keep the freezer full. Fill empty space with jugs or bags of water; frozen water is free ice.
  3. When a storm is on the forecast, turn the fridge down to 37°F and the freezer to 0°F.
  4. Freeze ice packs and water bottles you can move into the fridge or coolers later.
  5. Find out where you can buy ice and dry ice nearby.
  6. Have a cooler ready for drinks and things you reach for often, so the fridge can stay shut.

While the power is out

Keep the doors closed as much as you can, since every opening lets cold air out. Pack food together in the freezer, because a tightly packed freezer stays cold longer, and move the things you use most into a cooler with ice.

If you have a power station, you can run the fridge in cycles: an hour on, then one to two hours unplugged. That stretches a 1,000 Wh battery across a whole day. There’s more on this in how long a power station runs a fridge.

In winter, resist the urge to put food outside. Sun and swinging temperatures can thaw it, and animals will find it. A cooler in an unheated garage works, as long as it stays below 40°F.

Afterwards: what to keep and what to toss

When in doubt, throw it out, and never taste something to decide.

Usually toss if it’s been above 40°F for more than 2 hours

  • Raw or cooked meat, poultry and seafood
  • Milk, cream, yogurt and soft cheeses
  • Cooked leftovers, pasta and rice
  • Eggs and egg dishes
  • Deli meats and hot dogs
  • Cut fruit and vegetables
  • Mayonnaise-based salads and opened creamy dressings

Usually fine to keep

  • Hard cheeses like cheddar and parmesan
  • Butter and margarine
  • Whole, uncut fruit and vegetables
  • Ketchup, mustard, jam, pickles and soy sauce
  • Bread and baked goods without cream fillings
  • Peanut butter

From the freezer

Anything that still has ice crystals, or stayed at 40°F or below, can go back in the freezer. Food that fully thawed and sat above 40°F for two hours or more should be thrown away.

Is it worth backing up the fridge?

A full fridge for a family is easily worth $200–$400. A power station that keeps it cold through a typical outage costs more than one fridge-load of food, but it also runs the internet, lights and phones, and it does that every time the power goes out. The power station size calculator shows what size would cover your fridge for a day.