All bacteria that can ferment glucose or lactose to produce lactic acid are collectively called lactic acid bacteria, which are a group of quite complicated bacteria. At present, they can be divided into at least 18 genera, with more than 200 species of * * *. Except for a few, most of them are necessary for human body, have important physiological functions and widely exist in human intestine. At present, it has been confirmed by biologists at home and abroad that intestinal lactic acid bacteria are closely related to health and longevity.
Lactic acid bacteria can play a variety of physiological functions in animals. Lactic acid bacteria can promote animal growth, regulate normal flora of gastrointestinal tract, maintain microecological balance, improve gastrointestinal function, increase food digestibility and biological potency, reduce serum cholesterol, control endotoxin, inhibit the growth of spoilage bacteria in intestinal tract and improve immunity.