Lactenin

Lactenin is a nitrogenous substance present in milk. It has antimicrobial properties. The spermicidal property of lactenin is important, as milk is used as a semen extender in artificial insemination of animals. Lactenins will not be destroyed at normal pasteurization temperatures. It has some inhibitory action on Lancefield Group A Streptococci.

Lactenin in milk helps to preserve milk in the first few hours after milking but gets decomposed as temperature increases and is completely decomposed at 80 degrees Celsius making boiled milk more susceptible to coagulation than unboiled milk.