Louis Pasteur, a French chemist, developed the process of pasteurization in 1864, but not for milk. He was actually commissioned by Napoleon III to figure out why French wine and beer were frequently spoiling during transport. Pasteur discovered that microscopic organisms (bacteria and yeast) were responsible for the spoilage. He found that heating the liquid to a specific temperature—below its boiling point—for a short time would kill the harmful microbes without ruining the flavor. This discovery revolutionized the beverage industry, allowing for longer shelf lives and safer consumption. It wasn't until decades later that the process was widely applied to milk, which significantly reduced the spread of diseases like tuberculosis and typhoid fever.