Definition: freezing

Two main factors contribute to freezing being a method of preservation: the low temperature, which reduces the kinetics of many biochemical reactions, and the low activity of water, particularly through crystallisation (little free water as a solvent and medium for the diffusion of solutes).The formation of ice crystals in the product often causes deterioration, particularly of the texture when there is a lot of water and little cellulose.

As enzymatic reactions are only slowed down, it is useful to blanch food before freezing and possibly add inhibitors.

Important: freezing does not destroy the microorganisms (bacteria, etc.) responsible for food spoilage; it only stops their development during storage at -18°C.