Milk undergoes several processing steps after being collected from dairy farms. It is first pasteurized by being heated to 71.7°C for 25 seconds to kill harmful bacteria. It is then homogenized, which involves pushing the milk through narrow tubes under high pressure to break up and uniformly disperse the fat globules. The milk is packaged in bottles or containers, which helps extend its shelf life, and then distributed to stores. It can also be sterilized or undergo ultra-high temperature (UHT) treatment to further extend shelf life without refrigeration.