In the pasteurization process, usually a liquid is heated to a specific temperature for a predefined time period followed by immediately cooling step (E.g. 63-66 °C for 30 minutes or 71°C for 15 seconds). This was first invented by a French chemist and microbiologist, Louis Pasteur. This technique was first used to prevent souring of wine and beer, but lately milk was also pasteurized using this technique. Presently, this method is being widely used to extend the shelf life of milk