Yogurt and process for its preparation, Lactobacillus bulgaricus mutant and process for its selection

摘要

Long life yoghurt containing 106-1010 cells/ml of a mutant Lactobacillus bulgaricus from horse DNA is missing a fragment containing at least a portion of the beta-galactosidase gene, and 106-1010 cells/ml of Streptococcus thermophilus.