Here's a pretty straightforward article about it.http://candidaplan.com/blog/627/candida-diets-part-iii-bacillus-subtilis/
There's another forum about it on this site somewhere that I read. I also read another study that talks about the resiliency of the spore form of the b. subtilis that is used in probiotics and how it can be potentially dangerous. I think it's a matter that people should definitely take into consideration, considering there's so much we still don't fully understand about it. I definitely am not one to believe the FDA has the final word in safety.