Exactly what is the function of fermentation? Food and drink have been preserved by the process of fermentation since before refrigeration was commonplace. By manipulating the growth of microorganisms and the activity of enzymes, we may ferment foods and beverages, changing their chemical composition in the process. Organic substances such as sugars and starches are fermented by microorganisms like bacteria, yeast, or fungus into alcoholic beverages or organic acids. These are effective natural preservatives that also enhance the flavor and texture of fermented foods, giving them a signature strong, salty, and somewhat sour profile.