How good are frozen foods?

Frozen foods are still safe to eat but the quality of the food will degrade the longer they are frozen.

Frozen food keeps for a long time because the freezing of the water inside the food forces the bacteria, which cause it to decompose, into inactivity. Like all living things, bacteria need water in order to thrive.

Bacteria are microscopic organisms, or forms of life which occur in air, water and soil all over the world.  But they flourish and multiply particularly wherever organic matter is present. Some may cause disease, others are harmless, or even beneficial, but their activity causes organic matter, including food, to decompose.

Preserving food has an ancient history. The salting and smoking of fish and meat have been carried out for centuries. Another long-used method of preserving food is to change its form, for example turning milk into butter and cheese, and grapes into wine. More recently preservation has been effected by canning, heat being used to kill bacteria, or dehydration.

Most fresh food contains 75 to 90 per cent of water. When this liquid is removed, great savings in packaging, storage and transport are made. Potatoes, milk, eggs, tea and coffee are among the well-known products now sold as dry powders that need only the addition of water to reconstitute them.

Related:

How does sub-zero temperature obtained?