I made an account just to reply. First time I had kefir I was reading how unpasturized goats milk is the best way to go in terms of probiotics with kefir. So I ordered online and received the kefir and went on to drink a small carton and within the hour I was peeing blood and I got my first UTI with acute renal failure. It wasn't the kefir I'm sure, it was the milk.
Go and make your own water kefir and you won't be sorry, I love it and have had no problems.