At present, the main method of milk processing is ultra-high temperature instant sterilization, which can quickly kill bacteria and destroy hydrolase secreted by bacteria. Although the bacteria will not revive after being killed, the inactivated hydrolase may slowly recover its original protein structure during storage. Once they resurface, protein in milk will be hydrolyzed into peptides, and some peptides are bitter, which is why bitter milk is formed.
Judging from the causes of bitter milk, this kind of bagged milk will not have a significant impact on health, because peptides are harmless to the human body and can be digested and absorbed normally, so consumers need not worry too much. However, because such products seriously affect the taste, they should be avoided as much as possible.