I just happened upon this thread when googling probiotics, I had to register and write because I am a little confused.
First though, the response was brutal, I truly didn't feel you were attacking that person.
Anyways, I was always under the impression that assuming you had a few live cultures, you sterilized the milk, ie boiled it. The cultures would grow assuming they could use milk as a medium which I thought most lactic acid bacteria could do.
Perhaps it couldn't be done indefinetly as more species would eventually populate, but for a few runs, couldn't bacteria be cultured from a pill?