Data on the positive effect of sour milk products on human health have long been passed on, as early as 1965 Lilly and Stilwell described their beneficial effect on animal growth and stated that it was the effect of substances produced by microorganisms. Thus, probiotics were defined for the first time, which in the transferred meaning of the Greek words means that they are substances that are favorable "for life".
The definition of probiotics has been gradually refined. At present, they are perceived as mono- or polycultures of living microorganisms that have a beneficial effect on the intestinal microflora, and thus a health condition.