Louis Pasteur was one of the first scientists to understand the importance of microorganisms—both good and bad. Some microorganisms (or germs as Pasteur called them) are helpful, such as those that cause grapes to ferment and become wine, or those that cause milk to ripen and become cheese. Among his most important discoveries was pasteurization. This process kills harmful bacteria in liquids such as wine and milk, without destroying the liquid. For his many contributions to both medicine and industry, Louis Pasteur is remembered as one of the great minds of science.