Does rising sourdough starter always prove the presence of yeast?
I'm not sure if this has been asked before but I was wondering whether the fact that the starter could raise dough is proof it contains the correct yeast/bacteria for sourdough and is therefore perfectly safe to make bread with, or if there are other kinds of bacteria that could raise dough the same way that are either unsafe or won't taste very good. I know there are some bacteria that can make the starter bubble in when you first start it that are more or less harmless, but is there anything that would thrive in starter that is older that would simulate yeast by raising dough?
I am new to making bread and made a sourdough starter following the directions on this site (flour and pinapple juice to start, then flour and water until it could raise dough to double). The starter is about a month old now, although I haven't made anything with it yet. Its been in the fridge for the last few weeks and gets what I assume is hooch on top if I forget to feed it for too long (greyish water that smells distinctly alchol-like).
The problem is I have never seen or smelled starter in real life and while the starter doesn't smell bad, it just doesn't quite smell like what I expected given how baked sourdough bread smells. Its not moldy or oddly coloured or anything like that. I just want to make certain that it is definitely sourdough starter and not a colony of something else that I am baking with so I don't waste flour, or worse make someone sick :)