Louis Pasteur was a French chemist, biologist and microbiologist and is regarded as the founder of modern microbiology.
In 1854, upon becoming professor of chemistry at the Faculty of Sciences at Lille University, Pasteur began his studies on fermentation in response to requests from local manufacturers of alcoholic beverages.
At the time, the world of science believed alcoholic fermentation was a purely chemical phenomenon; Pasteur, on the other hand, successfully demonstrated the key role played by microorganisms, such as yeast, in this process.
Fermentation is actually the oldest method of food preservation known to man: it was used as far back as Neolithic times.
The most interesting fermentation agents that are widely used to produce fermented foods are lactic acid bacteria (LAB), as they produce lactic acid which helps prevent the growth of degradative bacteria. LAB are found throughout nature and in our digestive system, too.