there are bunch of kefir trademarks in my town and one local trademark is the best tasting and best saving in case of gastritis disease i once had and what is interesting it says to contain: "Whole cow's milk, skimmed cow's milk, sourdough on kefir fungi "
and as i know bacteriën and fungi is not the same.
once i did myself a soy yogurt out of soymilk powder, yogurt and sugar and that was the best gastronomic experience i have ever had
starter culture here can be bought both in food shops and in pharmacy stores in very different sets of probiotics