Twice a day the dairy farmer milks the cows. The milk goes into a sterile, refrigerated tank in the dairy barn and is held there until a tanker truck comes to load it up. The tanker truck is refrigerated and keeps the milk cold. The tanker truck hauls the milk to a processor. The processor processes the milk and puts it in cartons and bottles or jugs.
Processing means pasteurizing, taking out different amounts of fat, or adding chocolate flavoring.
The processor sells the milk to a food distributor. A refrigerated truck hauls the milk from the processor to a food distribution warehouse. The food distributor stores the milk in a refrigerated warehouse until it is sold and distributed to the grocery store. The milk is taken to the grocery store in a refrigerated truck. Grocers at the grocery store sell milk to their customers.