Probiotic and even prebiotic organisms have had many millennia to adapt to our food sources. In fact, some of our flora actually cam detox the more carcinogenic and problematic flavones and isoflavones. Ruminants may have developed multiple digestive chamber strategies for optimizing the benefits from such healthy flora. A brief peruse through the PDR reveals that many antibiotics are carcinogenic, either by themselves or by destroying beneficial flora along with the pathogens. Thus, developing natural immunity with foods our specie has evolved upon makes more sense than trashing our healthy flora with such drugs and with carcinogenic preservatives, sorbic/parasorbic acids and sorbates/parasorbates.