Have been having these doubts for some time, 0F/-18C "recommended" by FDA and similar Canadian health authority, while my meat and fish remain quite hard and I am still alive with freezer temps ranging from 10F/-12C to 7F/-14C.
So I did some research.
At 14F/-10C fatty fish remains edible for 2 months, and lean fish - 3 months:
blue line on the chart. 2 months seems like a long trip to me.
Was more difficult to find data for frozen meat, though here is a 60-days study of buffalo meat at 40F/4C and 14F/-10C, long and rather technical article. They found that 4 days in fridge and 30 days in freezer at 0F/10C is still good. See the
Conclusion. From the tables it follows that the microbial activity in freezer at 14F/-10C was DECREASING with time, all the way to the day 60.
So, - forget FDA guidelines 0F/18C. These are temps that will keep your food from spoiling indefinitely. You are not going to live indefinitely. If your fridge keeps 40F/4C, and freezer 14F/-10C - this is enough for most vacation trips and more than enough for a weekend trip. Don't lose your sleep over that. Manufacturers have detailed specs that consumers don't usually see - like max 0F in the center of freezing chamber and max 14F at the door, and even those max values you might not get in real life. I am not talking about deep freeze chests that can do -22F, those are different.
