Pasteurization is a technique for preserving food. It works by heating the food to a high temperature for about 30 minutes and then chilling. Milk, for example, is heated to 147 degrees Fahrenheit and then chilled to about 40 degrees.
Pasteurization was discovered by the French scientist Louis Pasteur, who discovered that bacteria makes food spoil. They may be killed by simply boiling the product. However, as in milk, this often ruins the taste. Pasteur discovered that the milk does not need to be boiled, and if chilled immediately afterwards, this process is just as effective as boiling. Pasteurization is used to preserve milk, beer, cheese, and other foods.