I've always got extra things growning in my worm bed -- from mold, to flies, to cornworms, to spiders. It has never seemed to bother my worms. The worst thing to happen to mine was when the chickens got in and ate most of the worms. I've thrown moldy fish feed, moldy chicken feed, and cracked corn with lots of little black bugs into the bin, and the food was all consumed. I've never tried the DMD grounds.
