L. S. DIFFERENTIAL MEDIUM BASE (LACTOBACILLUS STREPTOCOCCUS DIFFERENTIAL MEDIUM BASE)

L. S. (Lactobacillus Streptococcus) Differential Medium is used to differentiate Lactobacillus and Streptococcus. L. S. Medium is prepared according to the formulation of Eloy and Lacrosse and is a selective medium that supports good growth and differentiation of thermophilic lactobacilli and streptococci in yoghurt products. Yoghurt is a fermented milk product in which Streptococcus thermophillus and Lactobacillus bulgaricus are the essential microbial species and are active in a symbiotic relationship. A ratio of 1:1 is recommended by various workers. The reduction of triphenyl tetrazolium chloride in connection with the casein reaction allows differentiation between lactobacilli and streptococci by means of colony morphology.

for differentiation of Lactobacilli and Streptococci on the basis of colony morphology, TTC reduction and casein reaction