I have an old old bottle of hygrozyme (love this stuff) that I found; I forgot about this particular bottle. I have noticed that it is dark brown in color and smells even more "fermenty" than usual.

Wondering if it is still safe to use? I figure since it doesn't have any bacteria in it originally it should be fine, but then maybe it's brown and stinky because I introduced bacteria into the bottle somehow??

Any suggestions appreciated! I'll buy more anyways; just don't want to waste it