Whole milk develops oxidative rancidity during storage and it was scientifically proven that ingesting oxidation products might result in carcinogenesis . Poor quality raw milk contains more lipases, resulting in the production of more fatty acids. The presence of free fatty acids in milk fat contributes to the formation of off-flavor . Lipases from bacteria and milk are primarily responsible for the production of free fatty acids. According to research, milk fat is prone to oxidation .