Liquid milk can be delivered to the consumer after various heat treatments: none (raw milk), pasteurized or sterilized; and either packed or not (although sterilized milk is, of course, always packed). The properties of liquid milk that require the most attention are safety to the consumer, shelf life, and flavor. Safety is, of course, essential and consumption of raw milk cannot be considered safe. Consequently, the delivery of raw milk is prohibited or severely curtailed in many countries. Likewise, delivering milk that is not packed may involve a health hazard.