Abstract: Aimedto select excellent low-temperature lactic acid bacteria（LAB） strains from Tibetan traditional fermented yogurt and to find excellent lactic acid bacteria resources which could be used as the potential starter of fermented food,13 lactic acid bacteria strains from Tibetan natural fermented milk were used as test materials. Low temperature strains were screened at 10 ℃,and according to growth conditions at different temperatures,salt tolerance test,acid tolerance test,nitrite reduction test,amino acid decarboxylase test and indole test,processing characteristics of these strains were determined. Lactobacillus paracasei CD3 and CD5 cultured at 10℃ showed good qualities at salt tolerance,acid tolerance nitrite reduction and acid production capacity,and had negative results in arginine,ornithine and lysine decarboxylase tests and the indole test. Thus,Lactobacillus paracasei CD3 and CD5 could be used as excellent lactic acid bacteria strain resources of low-temperature fermentation.

Key words: Tibetan traditional fermented yogurt, low-temperature lactic acid bacteria, characteristic research