But, perhaps it was worth repeating, DDF! Thanks for that quote from the CrockPot site - I didn't think to look there. Doh me.
At any rate, 209 F = just over 98 C which is higher than Kerry (for instance) processed her garlic so I guess 'safe' is guaranteed .. but I would still want to set it to high I think so it would get past any danger zone as quickly as possible (but hey, I am not a food scientist so I am sure others can correct me there).
That said, while I am sure the results must have the same taste and texture, etc. as the longer processed ones do (or some would definitely notice the difference and comment), the nutritional changes (which I also think should be considered if one eats black garlic often) may still warrant using the longer method (at least 30 days - or at least to the extent that Kerry took hers). 90 days may be overkill.