RAW milk is either processed for beverage milks, creams, and related milk products for marketing, or is used for the manufacture of dairy products. Milk is defined in the U.S. Code of Federal Regulations and the Grade A Pasteurized Milk Ordinance (PMO). Milk products are defined in 21CFR131 to 135. Public Law 519 defines butter. Note that there are many nonstandard dairy based products that may be processed and manufactured by the equipment described in this chapter. Dairy plant operations include receiving raw milk; purchase of equipment, supplies, and services; processing milk and milk products; manufacture of frozen dairy desserts, butter, cheeses, and cultured products; packaging; maintenance of equipment and other facilities; quality control; sales and distribution; engineering; and research.