Considering humanity's pro-biotic ingestion is primarily, if not exclusively, through food I kinda doubt this is a major concern. I think what's more important

Considering humanity's pro-biotic ingestion is primarily, if not exclusively, through food I kinda doubt this is a major concern. I think what's more important is how changing diets affect gut flora more so than clean water or too much soap. There's research in this area and its pretty interesting. I doubt these guys haven't considered water. Its probably just a non-issue.