Pasteurized milk is milk that has been heated to a specific temperature for a set period of time to kill harmful bacteria and pathogens. This process helps to extend the shelf life of the milk and makes it safer for consumption. The method was developed by Louis Pasteur in the 19th century, which is why it is called pasteurization. After pasteurization, the milk is quickly cooled and packaged to maintain its freshness. Most milk sold in stores is pasteurized, ensuring that it is safe for people to drink. This process does not significantly change the nutritional value of the milk, making it a popular choice for many consumers.