What to throw out of the fridge after an outage.

Keep both doors shut. An unopened refrigerator holds a safe temperature for roughly four hours, a full freezer for about 48 hours, and a half full freezer for about 24. Once perishable food has been above 40 degrees Fahrenheit for more than two hours, it goes, whatever it looks like.

Every time the door opens, those numbers get shorter.

The numbers, and how to use them

Refrigerator, unopened: about 4 hours.
Full freezer, unopened: about 48 hours.
Half full freezer, unopened: about 24 hours.
The line is 40 degrees Fahrenheit. Above it for more than two hours, perishables are not safe.

Note that these assume the door stays shut. A fridge opened three times in the first hour does not hold for four.

An appliance thermometer in the fridge and one in the freezer turns all of this from guesswork into a reading. They cost very little and they are the single most useful thing you can buy before an outage.

What goes, once it has been warm

Meat, poultry, fish, and seafood. Dairy, including milk, cream, yogurt, and soft cheese. Eggs and anything containing them. Cooked leftovers, casseroles, soups, and stews. Cut fruit and cut vegetables. Cooked pasta and rice. Opened sauces containing dairy, meat, or eggs. Anything with a use by date that was already close.

What is usually fine

Hard cheeses, butter and margarine, whole uncut fruit and vegetables, bread and baked goods without a cream filling, opened jars of jam, peanut butter, most condiments including ketchup, mustard, and vinegar based sauces, and anything sealed and shelf stable to begin with.

The freezer, and the trick that answers it later

Frozen food that still has ice crystals, or that is still at 40 degrees or below, can be refrozen. The quality suffers, the safety does not.

Food that has fully thawed and been above 40 degrees for more than two hours goes.

The problem is knowing what happened while you were out. There is a well known and genuinely reliable answer: put a cup of water in the freezer, freeze it solid, then put a coin on top of the ice and leave it there permanently. If you come home and the coin is on the top, it stayed frozen. If it has sunk to the middle or the bottom, the freezer thawed and refroze, and you know without guessing.

Set that up this week, not during the next outage.

Making it last longer

Do not open the doors. Decide what you want before you open, and get it out in one go.
Move fridge items into the freezer early, while the freezer is still cold.
Fill empty freezer space with containers of water. A full freezer holds temperature roughly twice as long as a half empty one, and the frozen bottles double as a cold source afterwards.
Bags of ice or dry ice in the fridge, if you can get them. Handle dry ice with gloves and never in a sealed space.
A cooler for the things you actually need, so the fridge stays shut entirely.
A generator, run in rotation, is enough to keep both cold without running continuously. Where a generator has to be.

Insurance, which people do not think to claim

Many homeowners and renters policies include food spoilage cover, often with a modest sub-limit and sometimes without a deductible applying. Some require the outage to have been caused by a covered peril, some cover any outage over a stated duration.

Worth doing before you throw anything away:

Photograph the contents of the fridge and freezer.
Write a list with rough values.
Note when the power went off and when it came back.

Then check the policy or call and ask. What else is claimable after an outage.

Some utilities also have a claims process for spoilage after long outages, particularly where the outage was not weather related. It is usually capped and usually worth ten minutes.

After the power is back

Check the fridge and freezer are actually running and holding temperature.
Check the thermometers before restocking.
Clean up any thawed liquid, particularly raw meat drips, before it becomes a smell.
If the freezer failed rather than the supply, that is an appliance fault rather than an outage.

The short version

Doors shut. Four hours for a fridge, 48 for a full freezer, 24 for a half full one, and 40 degrees is the line. Ice crystals mean it can be refrozen. Never taste to check. Photograph and list before you throw it out, because food spoilage is often covered.