How long, really, is refrigerated food safe after a power outage?

I see many many sites, including the CDC, foodsafety.gov, usdairy.com, etc., that tell me which foods are safe to keep and which need to be tossed, *after four hours* with no refrigeration. I do not see a single site that tells me what to do if the food that was “safe” after four hours has now gone 24 hours with no power. Some of my questions are: unopened cheddar cheese, thickly grated Parmesan, an open package of tortillas, the jar of olives that is opened, and basically everything in the freezer, since I was out of town and not there to check for ice crystals.

What a nice day to give the fridge a thorough cleaning! 🙁

P.S., I will not be trying any of these foods but am not tossing the ones I have questions about until I resolve the question. No need to kill myself because I want to save a few dollars!


  • Comments (11)

    • 5

      A lot depends on the ambient temperature of the room, the mass and temperature of the food contained within the freezer/refrigerator and the quality of the insulation used in the construction of the refrigerator.

      Some foods such as chicken or shell fish should definitely be discarded if they have partially thawed and refrozen. Hard cheeses such as the ones you mention (and other hard fats) are less critical and will last unrefrigerated for several days in temperate places. (Soft fats, milk and cottage cheese will smell noticeably bad if they’re off) If the olives are still submerged in water/brine and not drained that will retard bacterial growth.

      Having said all that that if you live somewhere hot then bacterial growth is likely to be far faster.

    • 5


      It’s crude, but take a water bottle and freeze it upside down. Then place right side up as shown in the above picture. If my freezer ever loses power while I am out and gets warm enough to melt the ice, it will fall to the bottom and the air bubble will then be at the top. 

      Plus, it acts like a little ice block to give off coolness to the rest of the freezer and help keep temps low during a long term power outage. 

      For more adventures in my freezer…

      Another tip, at least for my fridge and freezer, there are areas which are cooler than others. For example, right in the back by the cooling element is colder than near the bottom front right corner of the fridge that is furthest away from the cooling element and also near the constantly opening and closing door. We used to store our cheese in this warmer spot just because it fit nicely near there but noticed that it would often mold before the expiration date. Since moving the cheese to the top back area of the fridge, we haven’t lost one to mold yet. So store lunch meat, cheese, and other more perishable items near the cooling element, and things like fruit, vegetables, or tortillas in the other areas.

      • 4

        I have a similar idea to Jay with a plastic fruit cup full of frozen water. I have a penny sitting on the top, if the power goes off while I’m away the penny will be at the bottom or part way down.

      • 1

        Oh! I love that idea. Much easier to see a penny either at the bottom or half way through the ice. 

    • 6

      Tortillas? LOL, we keep ours on the counter! 😛

      • 1

        That would be a good test. One tortilla on the counter and one in the fridge and see which lasts longer. I put mine in the fridge.

    • 3

      Unfortunately no site is really going to post things that contradict CDC or USDA because of liability.

      I wouldn’t hesitate to eat hard cheeses (in blocks, grated doesn’t last as long and you can’t just cut away the mold), tortillas would be just fine and don’t need to be refrigerated. Olives, pickles, jalapeños, most sauces are fine. Dairy, of course, would be a concern as would any refrigerated meats.

      Use it as an experiment: look for mold, smell them, look at texture. Learn now, while it’s safe and you do have options so you can be better prepared. There may be a time when you don’t have the same easy option of just throwing it away and buying new. 

      If you have chickens or other barnyard animals give the old stuff to them!

      Also if your refrigerator and/or freezer were kept close they can stay cold for a while. Maybe try another experiment and put a temperature prob in your freezer and see how cold it gets, and even try unplugging it and monitoring the probe and see how long it stays below 32 degrees? (Our large chest freezer, for example, stays at about 5 degrees and will stay below 32 for over 84 hours.)

      I like the penny in frozen ice idea!

      • 3

        Trace, good idea about running those tests with literally (almost) nothing in the freezer or fridge. I am definitely going to do the penny trick Jay pointed out. First time I have heard of that.

      • 2

        “Unfortunately no site is really going to post things that contradict CDC or USDA because of liability.” 

        True, but I also think we are talking about a separate issue here.  It would be helpful if rather than stopping at the arbitrary “four hour” example, entities like CDC and USDA published longer timetables of what to toss after 4, 8, 12, 24, 48, 72 hours, and 1, 2, and 3 weeks, say.  It seems kind of weird that they don’t.

    • 1

      i have a cafe and i store all those food items in my commercial cooler with backup power. it’s been more than 24 hours since the power is out, but the food can last for more than 48 hours. what i do is, i keep the food in the refrigerator section, but the temperature of the whole cooler is kept at 0 celcius. so the food is still safe. when the power is back, keep the food at room temperature for 2 hours to reduce the temperature; then bring the food back to the cooler, it will still be fresh for another 24 hours.

    • 1

      A couple of years ago we had a power outage that lasted about eight days.  We have external thermometers/temperature alarms on two freezers and two refrigerators.  Keeping in mind that refrigeration has a very narrow temperature range, far narrower than freezing, the temperature in both refrigerators (one in the house, one in an unheated building) exceeded 45 degrees in no time at all.  Outside temperature was in the 30s-40s.  We kept the temperature of both freezers (in the unheated building) easily within frozen range with intermittent use of a Honda 2200 generator.  Thanks to an abundance of ice provided by the storm, we quickly abandoned both refrigerators and transferred the food to ice chests.

      My take on refrigerators since that experience is that without power, they are useless after a few hours..especially if you open them, which of course, you have to do. How long to wait before discarding the food is kind of a judgment call. 

    • 4

      Speaking as someone who doesn’t even have a refrigerator, I would not worry at all about things like cheese, olives, or tortillas – these are not foods I pack into my tiny cooler when I have them!

      Pickled olives (like green olives in a jar) keep at least a few weeks in the pantry once opened, probably longer if we could refrain from eating them that long.  (Black olives in a can are not truly pickled, and spoil quickly once opened.) 

      Cheese and tortillas, in my opinion, are foods that are good as long as they seem good.  The first sign of spoilage should be visible and smell-able/taste-able mold, and even then my family always removed the moldy portion and ate them anyway when I was growing up.  While not exactly recommended, it never made any of us sick, either, and is a practice that long pre-dates modern refrigeration.

      Also, in the case of cheese, refrigerating it or not is more of a cultural preference than anything else.  I have friends originally from the UK who keep their cheese in a cheese box on the counter even though they do have a refrigerator, claiming that chilling it would ruin the flavor. 

      I think a good general rule of thumb is to consider how long something keeps in the refrigerator when considering whether or not a day or two at room temperature is actually dangerous.  Refrigerators slow the growth of bacteria, but they don’t stop it completely.  Things like raw meats or cooked meals, that only would have kept a few days in the refrigerator, could be quite dangerous after 24 hrs without power.  I would not eat them.  Things like cheese, condiments, pickles, or eggs (anything that lasts weeks or months with refrigeration) I have zero fear of eating after a day or two without.

      Obviously I’m not advising you to eat anything you’re not comfortable with, but the specific foods you mention are all things we routinely eat after days/weeks at room temperature, and I have never known anyone to get sick from doing so. 

      The freezer is a trickier issue because frozen food spoils so quickly once thawed.  If we’re talking about a chest freezer, and it was fairly full at the time, the food may have stayed frozen.  Are there clues?  Usually when a freezer fails something in there leaks and makes a mess in the bottom, or at the very least ice from the inside puddles in the bottom and refreezes.  Bags of frozen fruit will also turn to mush, then refreeze in to solid blocks.  If that sort of thing happened, my personal reaction would be to toss the riskiest foods (like chicken) and boil things like fruit for ten minutes before using them in cooking.  If there were no signs that it had thawed, I would assume it hadn’t, and basically use things as normal – but I wouldn’t serve that food to guests, just in case!