Today, milk appears in American grocery stores in a wide variety of forms designed to appeal to the tastes and needs of individual consumers.  The distinguishing characteristics of the most popular types of milk are described below.

Milk is one of the most carefully tested and heavily regulated foods available.  One of the most effective instruments for assuring the quality and purity of milk is the Pasteurized Milk Ordinance (PMO), a set of reccommendations from the U.S. Public Health Service/Food & Drug Administration (FDA) for voluntary adoption by state and local governments (which often enact even more stringent requirements for milk produced within their jurisdictions).  The descriptions below reflect the requirements of the PMO for various types of milk.