Louis Pasteur is considered a founder of which branch of science?

Louis Pasteur is considered one of the founders of microbiology. His experiments demonstrated that microscopic organisms drive processes such as fermentation and can cause disease, transforming both laboratory science and medicine.

Pasteur began as a chemist studying crystals and molecular asymmetry, but his investigations into wine, beer, and fermentation led him toward the microbial world. In the 1850s and 1860s, he argued that specific microorganisms were responsible for particular fermentations. His swan-neck flask experiments also provided powerful evidence against spontaneous generation.

His work helped establish germ theory and inspired practical methods for controlling microbes, including pasteurization. Pasteur also developed vaccines for chicken cholera, anthrax, and rabies. Bacteriology is a closely related term and describes the study of bacteria; microbiology is broader, encompassing bacteria, fungi, protozoa, and other microscopic life. Virology, by contrast, focuses specifically on viruses.