傳統的食物發酵過程可以大致分為乳酸發酵、真菌發酵、鹼性發酵。Traditional food fermentation processes can be broadly classified into lactic acid fermentation, fungal fermentation, and alkaline fermentation. Examples of lactic acid fermented products, i.e., products primarily fermented by lactic acid bacteria, include yoghurt, sausages, cheese, sauerkraut (fermented cabbage from eastern and central Europe), and kimchi (fermented and spiced Napa cabbage from Korea). Yeast spp. are also involved in the fermentation of many of the lactic acid–fermented products, including kefir (a slightly alcoholic dairy beverage from the Caucasus), and kombucha (a fermented sweetened tea from China). Most of the well-known soy-based fermented foods from Asia such as tempeh and soy sauce are produced by fungal fermentation, except natto, which is produced by alkaline fermentation (Dirar, 1992)