For propogation, cultivation and maintaince of L.leichmannii ATCC 7830. B12 Culture Agar recommended by USP for cultivation and maintenance of Lactobacillus leichmannii ATCC 7830 which is used as a test bacterium during microbiological estimation of vitamin B12.Lactobacillus species have very exacting nutritional requirements for amino acids and vitamins.Kulp found that the growth of lactobacillus acidophilus was enhanced with tomato juice, while investigating the use of tomato juice on bacterial development, which was reported earlier by Mickle and breed for microbiological assay of vitamins. Medium contains Peptic digest of animal tissue serves as a source of nitrogen and amino acids. Yeast extract is the vitamin source. Tomato juice is added to create the proper acidic environment. Dextrose is the carbon source and Polysorbate 80 acts as an emulsifier. Monopotassium phosphate provides buffering capacity.