The thread below about the dishwasher is prompting this post. Recently, my white polypropylene cutting board and my yellow tupperware bowl, when coming out of the dishwasher have little black spots on them. I can scrub them clean, but this is a new phenomenon. What's going on? All the other dishes come out nice and clean. Could the "food grade" protection on these items have gone kaput? It's totally weird. My other clear tupperware doesn't get this, only the yellow bowl that has kind of a roughed interior.
P.S. My dishwasher is a Bosch with a stainless steel interior, I've checked the filter and it uses condensation drying.