How does food go bad when it’s in the freezer?


Like for example that I shouldn’t put eggs in the freezer for more than 8 months or meat for longer than 12 months. How does it go bad when it’s frozen? Especially considering that we find hundreds of years old things/people frozen in ice and they seem to be in pretty good condition?

In: 0

It doesn’t go “bad” like it’s unsafe to eat. The recommended storage time is the time in which food should be used to insure maximum quality. Food stored longer than recommended time is safe but flavor, color and texture will continue to deteriorate.

Water evaporates off the surface of food because of temperature fluctuations. Items in a freezer are usually not completely enclosed in ice or another material. Even if they are wrapped somewhat tightly, they are surrounded by pockets of air. Food may also accumulate smells of other things in the freezer.

In this case, it’s *generally* not spoiling due to bacterial activity, but rather it becomes unpalatable or otherwise undesirable.

One culprit is oxidation. This is basically food ‘rusting’. Think meat and fruit turning brown.

Another issue is cellular degradation. In a normal freezer, ice inside and around the cells form crystals which break the cells and degrade the tissue.

These two problems combined are generally referred to as ‘freezer burn’. ~~They are amplified by the fact that many modern freezers *don’t continuously freeze.*. They are self-defrosting, so they come up slightly above freezing to defrost for a brief period of time. These freeze-thaw cycles can degrade the food like winters cause potholes. They also provide brief windows for slow bacterial growth.~~

Food is chemicals and chemicals will degrade even when frozen. There is no bacterial growth, but the quality of the food will degrade to the point where it will not taste the same anymore.

This is why in research settings liquid nitrogen is used for preserving biological and sometimes chemical samples for a very long time. 0 degrees C is still very far above absolute zero and chemical reactions do still happen.