Sterilization
The U.S. Food and Drug Administration reports that raw milk can carry dangerous bacteria like Salmonella, E. coli and Listeria, all of which may pose a significant risk to your health. Pasteurization kills these harmful bacteria, though it may leave other nonpathogenic bacteria that can still cause milk spoilage. Ultra-pasteurization effectively kills all bacteria in the milk. Removal of these bacteria may alter the flavor of the milk.