There is a big problem, you know the spinning iron stick that connects to 3 different heads, around it there is some dark machine grease, which sometimes turns into crust and falls into the mixture without you noticing.
I noticed it when i was making mashed patatos, if patatos were not bright color, i would have not noticed it and probably ended up eating it. Get more detail about KitchenAid KSM150PSER Artisan Series 5-Quart Mixer, Empire Red.