Pasteurization is a process of heating food or drinks to kill harmful bacteria and make them safer to consume. Named after French scientist Louis Pasteur, who developed the method in the 1860s, pasteurization heats liquids like milk or juice to a specific temperature for a set amount of time, then cools them quickly.

Before pasteurization, people regularly got sick from drinking milk contaminated with dangerous bacteria. Pasteur discovered that gentle heating could eliminate these microorganisms without ruining the taste or nutritional value of the food. His breakthrough transformed public health: diseases like tuberculosis and typhoid fever, once commonly spread through milk, became far less common.

Today, most milk, juice, and many other beverages you find at the grocery store are pasteurized. The process happens before the products reach stores, which is why refrigerated milk stays fresh for days or even weeks. Some people prefer unpasteurized or “raw” milk, but health experts warn that it carries risks of bacterial infection that pasteurization helps prevent.

The word pasteurize means to treat food with this process. When you see “pasteurized” on a carton of orange juice or a bottle of milk, it means the product has been heated carefully to protect your health.