<P> In microorganisms, fermentation is the primary means of producing ATP by the degradation of organic nutrients anaerobically . Humans have used fermentation to produce foodstuffs and beverages since the Neolithic age . For example, fermentation is used for preservation in a process that produces lactic acid as found in such sour foods as pickled cucumbers, kimchi and yogurt (see fermentation in food processing), as well as for producing alcoholic beverages such as wine (see fermentation in winemaking) and beer . Fermentation occurs within the gastrointestinal tracts of all animals, including humans . </P> <P> Below are some definitions of fermentation . They range from informal, general usages to more scientific definitions . </P> <Ol> <Li> Preservation methods for food via microorganisms (general use). </Li> <Li> Any process that produces alcoholic beverages or acidic dairy products (general use). </Li> <Li> Any large - scale microbial process occurring with or without air (common definition used in industry). </Li> <Li> Any energy - releasing metabolic process that takes place only under anaerobic conditions (becoming more scientific). </Li> <Li> Any metabolic process that releases energy from a sugar or other organic molecule, does not require oxygen or an electron transport system, and uses an organic molecule as the final electron acceptor (most scientific). </Li> </Ol> <Li> Preservation methods for food via microorganisms (general use). </Li>

Where do you think the bacteria for these fermentation came from