Question: We recently had a power blackout over night. How do I know if my frozen food is OK? Answer:
According to Food Safety Victoria, if the power has been off for more than 5 hours then you will need to check the food at the time the power is restored. If it shows no sign of thawing (meat still hard, cardboard not soggy) then the food will be fine to use. If any products show signs of thawing, then they really should be destroyed.
Factors such as the temperature of the freezer at the time of the blackout, the time of year and amount of food in the freezer can influence how quickly the freezer temperature will drop.
If you are ever in doubt as to the length of time the freezer has been off or if you are unsure of the state of the food, then you should discard it.