High pressure carbon dioxide (HPCD) treatment is currently considered as an attractive non-thermal process for preserving food, which is gaining growing interest as an alternative for heat pasteurization of food.Bovine milk is one kind of high-risk food materials because of the growth of the microorganisms.During the processes of pasteurization or UHT, most of psychrophilic bacteria do not survive, but those heat-resistant extracellular proteases and lipase secreted by them could have keep activities and deteriorated the quality of milk.