Herbal oils and mold

A post on the herblist caught my eye, and I promptly disarmed a myth-to-be.

Here's the budding myth in all its glory:

"but rancid oil, apart from anything else, is on the verge of growing mold"

Here's my reply:
I don't think so - if there's no water in the oil, and there isn't if it's made properly (either from dried herb to start with - and being careful about not letting any water drip into the oil while pouring things off waterbaths and so on either, or letting it stand and clear for a while and then decanting it off the bottom muck), then nothing will grow in that oil. No water to grow with.

On that note, any herbal oil or salve that doesn't contain water will be completely sterile after 4 days, nevermind what dirty fingers have touched it: any spores (bacteria, mold, whatever) it got from those dirty fingers will try to grow during those 4 days, and promptly die.

That little tidbit is brought to you by the magic of the internet: it was discussed on one or the other herbalists' discussion list a couple years ago, and I remembered it. I think it was an ex-chemist turned practising herbalist who said it, but I'm not sure.