It’s not my fault. That Marcus sent me this link knowing full well I wouldn’t be able to resist passing it on to you. He was lamenting the continuing hype and missinformation put out about bread and this is a good example. Apart from the fact that starters are affected by local yeasts and bacteria so your little sachet isn’t going to stay “authentic” very long, they don’t even seems to realise that ” Lactobacillus Sanfrancisco” (don’t you mean Sanfranciscensis?) is bacteria and not yeast.
Hey Ho.
The PArtisan Baker 
Ha ha I love it when so called ‘experts’ get it wrong, mind you if you want to have ‘authentic’ sanfransisco sourdough you would just need to buy his starters every time you bake, probably what he wants you to do. LOL
Had a useful response from a long-time correspondent Charles Perry: “I can tell you from my reading of various bogs and newsgroups over many years that there have been more reported complaints than happy endorsements of the sourdough product on offer at the link you posted.
I think you are painting with too broad a brush when you talk about the instability of starters. Many starters are apparently not stable when the geographic location is changed. However, some are quite stable. I do not have a DNA lab, however over the past 14+ years I have grown and mailed out over 36,000 (free) starts to every continent on the globe. I have accumulated a fair amount of anecdotal information on the behavior of starter from internet conversations with recipients of the start.”
Thats interesting, but surely enviromental conditions and local flora will affect the flora of a sourdough starter.
You wouldn’t exactly call me a man of science but I assume that these cultures are so stable they can take on all comers