The determination and the fermentability identification of lactic acid bacteria in Tibetan traditional fermented milk

Objective—To research on the musculomyces and the relevant function of lactic acid bacteria in the traditional fermented milk in Tibetan area.Methods—The evaluation and performance test analysis of traditional fermented milk is done which is collected from five counties in Tibet,namely,Damxung,Naqu baru,Qamdo Baxiu,Shannan Zhanang and Rigezejiangzi.Results—There is 1strain of Lactobacillus bulgaricus,3strains of Lactobacillus casei and 1strain of Lactobacillus plantarum in the traditional fermented milk in Tibetan.By testing the bacteriostatic functions of isolation strains,it was found that s012-2strain can inhibits Gram-negative bacteria except that all of the five strains can inhibit Gram-positive bacteria.In terms of organic acid produced by bacteria strain and growth rate,it was found that only s007-2produced organic acid but grew slightly slowly,or even hardly grew.S017-1hardly grew during 8~16hbut quickly and produced organic acid during 10~14h.Other three of five bacteria strains grew and produced organic acid quickly during 8~16h,steadily during 16~20h.Conclusion—The test of the determination and fermentability identification of bacteria strain obtained from the traditional fermented milk by isolation is of great significance to setting the best fermentation process or applying the best bacteria strain to food industry.