Who is Louis Pasteur from On Food and Cooking and what is their importance?

French chemist, Louis Pasteur, invented the process of pasteurization. Originally developed to lengthen the shelf life of alcohol, Pasteur's invention led to the pathogen-killing heat treatment that allowed milk and several other products to be enjoyed by those who didn't live on farms. Pasteur also introduced the use of standard, purified microbial cultures to make cheeses and other fermented foods. His investigations in the 1850s led to the discovery of the nature of the leavening process, vital to raising breads. In essence, Pasteur's work in chemistry gave rise to such concepts as microbiology and other major areas associated with food science.