One of the major concerns you might have when losing power to your home is your fridge and freezer and how long frozen food will stay safe during a power outage.
The last thing you want it to lose hundreds of dollars worth of food because it thawed out and spoiled. So how long exactly does food stay frozen when you lose power?
In an upright freezer food will stay frozen for approximately 24-48 hours if you don't open it. In a deep freezer (with a top lid) food will stay frozen for 48-72 hours. You can extend the life of your frozen food by using dry ice, regular ice or putting your food in a high-end cooler or deep freezer with ice.
How Long Do Different Types of Food Last During a Power Outage?
Not all food is created equal and some food keeps longer than others when you have a power outage and they start to thaw out.
Meats and Fish
Frozen meats (and fish) carry the most risk out of any frozen foods, they are also usually the most expensive frozen foods you'll have.
Since they are technically parts of dead animals, they produce a great deal of bacteria as part of their decomposition process.
In a full freezer, meat can keep for up to 48 hours and 24 in a half-full freezer. Meat can still be refrigerated and cold for another 24-48 hours after that.
But once the temperature of the meat gets above 40ºF (4ºC) then it enters what the USDA calls the “danger zone”. At these temperatures bacteria can grow rapidly and so your meat should be eaten without a couple of hours or thrown out.
Frozen fruits are a tough one because the outsides of the fruit can start to thaw out in as little as 6-12 hours and the fruit can completely thaw in 24-48 hours.
They can be refrozen but often the textural integrity of the fruit will be ruined after thawing and refreezing.
Still ok for smoothies and juices but probably not enjoyable to eat otherwise.
The only vegetable products that will survive longer than the 24- or 48-hour mark are herbs, spices, and uncut whole vegetables.
Nuts are also okay. All other vegetable products, including tofu, must be thrown away.
Frozen Microwave Meals
Frozen microwave meals or other frozen meals (such as a whole cooked casserole or frozen pizza) are a little bit trickier.
It really depends on what is in them. You will want to discard them as soon as any of the ingredients reach their limit.
This includes any dairy in sauces or meat, whether previously cooked or uncooked.
Generally speaking you'll have 24-48 hours before these completely thaw out and start to go bad.
Ice Cream and Other Dairy Products
While ice cream and other dairy products may remain safe to eat on the same timeline as meats (24 or 48 hours), they will melt much more quickly and lose quality if they are defrosted and then refrozen.
Ice cream will start to melt within just a few hours and likely within 12-24 hours it'll be completely liquid.
Refreezing doesn't work because it will form larger ice crystals and the ice cream will be more solid and icy and less fluffy.
It is probably best to throw thawed dairy products away.
Breads and Starches
In general, breads and pastries can be completely defrosted and then refrozen, so there’s no need to throw these away even after the 48-hour mark has passed.
The exception is pastries that contain perishable ingredients, such as cakes and pies.
Water Based Items
Frozen foods that are water-based, such as popsicles and ice, can be completely thawed and refrozen with no danger.
That said, if their container won’t hold their shape (such as a popsicle in plastic wrapping) then they might be quite messy.
What Can You Do to Prevent Food Spoilage During a Power Outage?
If you've had a power outage how can you extend the life of your food so it doesn't go bad while you wait for the power to come back on?
Don't Open The Freezer Door
The most basic step that you can take during a power outage to prevent food from spoiling is to not open the refrigerator or freezer doors.
This is very important!
The 24- and 48-hour marks drastically reduce every time the freezer is opened, as cool air floods out and warmer air circulates inside.
Since there is no power source, your freezer is unable to pump in cold air to compensate.
The longer you can keep the cold air in, the better chance you have at saving the food.
Have a Backup Power Source
The best method for preventing food spoilage due to a power outage is to have a backup power source, such as a generator.
New generator models are able to be programmed to deliver power only to certain appliances or circuits, prolonging the life of your food.
I personally have a Goal Zero Yeti battery/generator that lives in my campervan. But if my house has a power outage I can bring it inside and use it to power my fridge, my devices and some lights.
Use Dry Ice or Regular Ice
Get some dry ice or regular ice from the store and place that in your freezer to keep down the temperature.
Dry ice is super cold at -109ºF (-78ºC) and so it can actively keep things frozen. Regular ice will more keep things cold and delay the thawing process.
Use a Cooler
While a freezer and fridge are great at keeping food cold when you have power they aren't the greatest when the power dies.
The front door design means that every time you open them lots of cold air is lost and replaced by the warmer air from the room.
The shelves also spread out the food which leads the food to warm up quicker.
Taking your food out of the freezer and putting it in a cooler filled with ice (or dry ice) can extend the life of your food by days or even week if you've got one of the best coolers for keeping ice for a long time.
Why Does Frozen Food Need to Remain Frozen?
Some frozen food is kept frozen because of its consistency; for example, ice cream and popsicles are meant to be enjoyed cold. However, most freezer foods are frozen in order to retain freshness and prevent spoilage.
When foods are frozen, it is much harder for harmful bacteria to multiply on them.
According to the United States Center for Disease Control and Prevention, foodborne germs are responsible for more than 48 million illnesses and approximately 3000 every year in the US alone.
These bacteria, as well as others, are unable to multiply at frozen temperatures. As soon as the product on which they are living begins to warm, however, they immediately begin reproducing in numbers that can make humans sick.
The amount of time that you have to salvage your food depends on how full your freezer is before you lose power as well as what type of freezer you have. More on how long a deep freezer stays frozen without power.
The more food in your freezer, the better, as the food insulates itself and allows less room for warm air.