Bacillus Subtilis was used as Antibiotics not that long ago and it was used for military men in Germany the scientist had stumbled on a secret this strain healed all the digestive problems naturally and saved countless lives of many German military men. So I would say it is safe, but I always wonder about putting all the different strains together in one yogurt batch, is it safe or is it too much as a microbioligist that works for the yogurt company...