There is some store bought brands like Lifeway that say they have all of 10 beneficial strains in their kefir. But here's the thing... they take dead milk and fill it with the strains... REAL kefir has over 40 strains or something crazy like that to the tune of trillions. Grow you're own... you'll be MUCH better off in my opinion. Plus... the lifeway stuff is expensive. For about the same price you buy their 32oz of pretend "kefir"... you can grow 128oz...