No easy answer that I know. You probably know molds are fungi and different than bacteria. The 'good' molds I know are grown in a controlled way. Like the blue on/in some cheese. I've heard non-blue cheeese with light gray or blue mold on it can just have it cut off but if the mold is dark or black the cheese should be tossed. Moldly fruit and grain in general tastes poor to me and there the risk of aflatoxin (not healthy at all) in some cases. Some molds like koji (a type of Aspergillus sp.) however make rice much more sweet (that's how amazake and sake is made). Tempeh and su-fu use other kinds of mold and the preservative value of the mold is arguably as important as it's effect on taste and health. I gotta go work on some Saccharomyces produced products (this yeast also enhances B vitamins) at the moment but check out this site (some of the cultures are bacterial)- users.chariot.net.au/~dna/koji.html