Fermentation is a process where certain so-called "good" or "preferable" microbes living on the surface of plants flourish and feed on those plants, supressing the growth of "bad" bacteria. These microbes also produce substances like lactic acid and alcohol, preserving food's texture and nutrients and enhancing its taste and flavor.
Commonly fermented foods and drinks include wine and bread, where yeast is encouraged to consume sugar. To make olives, preserved lemons, sauerkraut and pickles, vegetables are submerged in brine to create the proper oxygen-free atmosphere for good bacteria to flourish, extending their shelf-life.
