A process during which a liquid such as milk is rapidly heated almost to the boiling point and is then rapidly cooled. The purpose of this process is to kill the bacteria in the liquid without damaging its taste or nutritional value. The process prolongs the shelf life of the liquid. The process is named after the scientist Louis Pasteur, who invented it. The classic process of pasteurization is: heating to a temperature of 63 degrees celsius for 30 minutes. Another alternative is heating to a temperature of 72 degrees celsius for half a minute.