Identification of Yeasts Present in Sour Fermented Foods and Fodders

Lactic acid fermentation is commonly used for food conservation. The main products of this bacterial process are lactic and acetic acids, which are toxic to many microorganisms, most yeasts included. The low pH achieved by the lactic acid fermentation, together with anaerobiosis, provides conditions adverse to spoiling and pathogenic microorganisms. Hence, the fermented commodities are stable and can be stored for a long time without loss of quality. The production of sauerkraut is a good example of this practice. In the dairy industry, buttermilk and yogurt are well-known products. This application of the lactic acid fermentation originated from central Asia in times immemorial and has spread from there to Europe and the Orient. It was unknown in other continents until these were colonized from Europe.