Explain Pasteurization (temperature below 100° C) - method of food preservation?

Pasteurization is a heat treatment that kills a part but not all the microorganisms present and usually involves the application of temperatures below 100° C. Milk, for example, is usually heated to 63° C for 30 min or 71° C for 15 seconds or in UHT, 138° C for 2-4 seconds. Examples are: milk, wine, beer, fruit juices and aerated waters are routinely pasteurized. The heating may be by means of steam, hot water, dry heat or electric currents and the products are cooled promptly after the heat treatment. Pasteurization is usually supplemented by other methods to prolong shelf-life.