pasteurization

pasteurization [pas΄chər i zā′shən, pas΄təri zā′shən]

n.

〚Fr: see PASTEURIZE & -ATION〛

a method of destroying disease-producing bacteria and checking the activity of fermentative bacteria, as in milk, beer, or cider, by heating the liquid to a prescribed temperature for a specified period of time

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pas·teur·i·za·tion (păs'chər-ĭ-zāʹshən, păs'tər-) n.

1. The act or process of heating a beverage or other food, such as milk or beer, to a specific temperature for a specific period of time in order to kill microorganisms that could cause disease, spoilage, or undesired fermentation.

2. The act or process of destroying most microorganisms in certain foods, such as fish or clam meat, by irradiating them with gamma rays or other radiation to prevent spoilage.

  [After Pasteur, Louis.]

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Partial sterilization of a substance, especially milk or other beverages, by using heat to destroy microorganisms while leaving its chemical makeup unaltered.

The process is named for Louis Pasteur, its originator. Pasteurization of milk requires temperatures of about 145 °F (63 °C) for about 30 minutes, or higher temperatures for shorter periods. The treatment destroys any disease-causing organisms (principally Mycobacterium tuberculosis) as well as organisms that cause spoilage. See also food preservation.

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▪ heating process

      heat-treatment process that destroys pathogenic microorganisms in certain foods and beverages. It is named for the French scientist Louis Pasteur (Pasteur, Louis), who in the 1860s demonstrated that abnormal fermentation of wine and beer could be prevented by heating the beverages to about 57° C (135° F) for a few minutes. Pasteurization of milk, widely practiced in several countries, notably the United States, requires temperatures of about 63° C (145° F) maintained for 30 minutes or, alternatively, heating to a higher temperature, 72° C (162° F), and holding for 15 seconds (and yet higher temperatures for shorter periods of time). The times and temperatures are those determined to be necessary to destroy the Mycobacterium tuberculosis and other more heat-resistant of the non-spore-forming, disease-causing microorganisms found in milk. The treatment also destroys most of the microorganisms that cause spoilage and so prolongs the storage time of food.

      Ultra-high-temperature (UHT) pasteurization involves heating milk or cream to 138°to 150° C (280° to 302° F) for one or two seconds. Packaged in sterile, hermetically sealed containers, UHT milk may be stored without refrigeration for months. Ultrapasteurized milk and cream are heated to at least 138° C for at least two seconds, but because of less stringent packaging they must be refrigerated. Shelf life is extended to 60–90 days. After opening, spoilage times for both UHT and ultrapasteurized products are similar to those of conventionally pasteurized products.

      Pasteurization of some solid foods involves a mild heat treatment, the exact definition of which depends on the food. Radiation pasteurization refers to the application of small amounts of beta or gamma rays to foods to increase their storage time.

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