摘要：In the investigated case the lactic acid fermentation was inhibited in fermented milks production. After the experiments which have eliminated other possible reasons, it was proved in three simple ways that the bacteriophages caused the inhibition: By adding milk where the lactic acid fermentation was inhibited (1 %) to the milk first checked using bio-test, and controlling its fermentation after inoculation with the culture. This procedure was repeated, so that dilution of the inhibitory source was 10.000 times; By using the three different strains of mixed microbiological culture (S. thermophilus and L. bulgaricus) for the lactic acid fermentation in the presence of the inhibitory source (1 % milk where the fermentation was inhibited) and controlling the fermentation; By elimination of Ca^2+ from the solution bounding it with added phosphate and controlling the lactic acid fermentation in the presence of the inhibitory source (1 % milk where the fermentation was inhibited).
