Thermization of milk

Thermization of milk is a ‘heat treatment not equivalent to pasteurization’. There is no legal definition nor criteria for thermization. The thermization process is a subpasteurization heat treatment of milk at 62–65 °C for 10–20 s, followed by refrigeration.

Thermization should be applied soon after milk treatment and it is only effective if thermized milk is kept cool (4 °C).

Thermization markedly reduces the number of spoilage bacteria with minimum collateral heat damage to milk components and it does not cause changes in flavor. It is used as a prepasteurization treatment of raw milk to safeguard milk quality during prolonged storage in insulated silos. The process is also used as a postpasteurization treatment of dairy products.

The purpose of this treatment is to protect against microorganisms that may grow during storage of raw milk, especially Gram-negative psychotropic bacteria.

Thermization allows the milk to be stored below 8 °C (46 °F) for three days, or stored at 0–1 °C (32–34 °F) for seven days. Later, the milk may be given stronger heat treatment to be preserved longer. Cooling thermized milk before reheating is necessary to delay/prevent the outgrowth of bacterial spores.
Thermization of milk