I don't know about powder, but everytime I put lotion on, Roxy proceeds to lick it off. Maybe that would explain her sometimes "strange???" behavior. LOL, just kidding. I don't think a little powder will cause any harm, besides, look at what they like to eat.........WORMS, BUGS, POOP!!!!
Go to the "What's the strangest thing your yorkie has ever eaten" thread, you won't worry about a little powder after reading that.