# Freezer warmed to -6C. Safe to eat the food?

My freezer recently warmed to -6 degrees Centigrade during a long power outage from its usual -18C. It's now on its super freeze cycle and cooling back down again. Is the food inside still safe to eat? -6 is obviously less than zero, the freezing point of water, but I've heard that food in a freezer can go bad even below 0. Is this true?

• how long was it at that temperature? Sep 15, 2014 at 14:53
• @KateGregory: Not for very long. It's kept inside our utility room which is at about +15C therefore it would have kept on warming had the power not come back on then [i.e. -6C was not close to ambient temperature outside of the freezer]. I would therefore hazard a guess at under half an hour at that temperature. Thanks for the edit and help by the way :) Sep 15, 2014 at 14:58
• -6C is still freezing, you should be good.
– GdD
Sep 15, 2014 at 15:45
• "I've heard that food in a freezer can go bad even below 0" Yes, bacteria are still multiplying, just slower. At -18, it's deemed safe indefinitely (source: EU and USA government websites) with a tolerance of 3°C (source: EU legislation). Above that, it will spoil, just much much slower than at room temperature. According to the star rating system, -6°C keeps "three or four days" and -12°C "fifteen to twenty days". Why -18°C is said to be three months is beyond me though, so these probably err on the side of caution.
– Luc
Sep 22, 2020 at 1:30
• Note that these are cumulative times. If your food spent 3 days at -6°C (where 4 days at -6°C is considered safe), then storing it at -12 will only be good for another ¼ of those "fifteen to twenty days" i.e. up to 5 more days (if those values are to be taken literally, which I doubt; it's about the concept). As an example, let's say 20 bacteria is the allowance and at -6°C they double every day (2× per day) whereas at -12 they multiply by 1.25× per day, then you can count out at which point 1 bacterium turns into 20.
– Luc
Sep 22, 2020 at 1:33