According to the U.S. Food and Drug Administration (FDA), foods kept at a constant temperature of 0° F are safe . But in reality, most home freezers do not keep a constant temperature below 0° F. Freezing at or below 0° F inactivates bacteria, mold and yeast. Molecules stop moving when frozen and thus micro organisms can no longer grow. But remember, once thawed they again become active. Another important point to realize is that home freezers do not get cold enough to destroy parasites. So, when freezing foods begin with good food so that the freshness, nutrients and quality will be preserved.
Most foods can be frozen, but with varying degrees of success. Canned goods and eggs still in the shell are the exception… You may remove the food from the can or shell and then freeze it, but never freeze foods in cans or shells. Some foods, for instance creams, mayonnaise and certain fresh vegetables like lettuce drastically change when frozen and become undesirable (although safe). These products are noted within the Eat By Date pages.
It is also important to note that enzyme activity is slowed by the freezing process, but is not completely stopped.