First, Dairy cows are milked twice a day using mechanical vacuum milking machines. The raw milk flows through stainless steel or glass pipes to a refrigerated bulk milk tank where it is cooled to about 40° F. Then, A refrigerated bulk tank truck makes collections from dairy farms in the area within a few hours. Before pumping the milk from each farm's tank, the driver collects a sample and checks the flavor and temperature and records the volume. Next, At the milk processing plant, the milk in the truck is weighed and is pumped into refrigerated tanks in the plant through flexible stainless steel or plastic hoses. Then, The cold raw milk passes through either a clarifier or a separator, which spins the milk through a series of conical disks inside an enclosure. A clarifier removes debris, some bacteria, and any sediment that may be present in the raw milk. A separator performs the same task, but also separates the heavier milk fat from the lighter milk to produce both cream and skim milk. After this, Vitamins A and D may be added to the milk at this time by a peristaltic pump, a clarifier removes debris, some bacteria, and any sediment that may be present in the raw milk. The milk is then fortified and pasteurized. This automatically dispenses the correct amount of vitamin concentrate into the flow of milk. Then, the milk - either whole milk, skim milk, or standardized milk is piped into a pasteurizer to kill any bacteria. Next, Most milk is homogenized to reduce the size of the remaining milk fat particles. This prevents the milk fat from separating and floating to the surface as cream. It also ensures that the milk fat will be evenly distributed through the milk. The hot milk from the pasteurizer is pressurized to 2,500-3,000 Pounds per square inch by a multiple - cylinder piston pump and is forced through very small passages in an adjustable valve. The shearing effect of being forced through the tiny openings breaks down the fat particles into the proper size. Then, The milk is then quickly cooled to 40° F to avoid harming its taste. Finally, The milk is pumped into coated paper cartons or plastic bottles and is sealed.