From The Black Folks Don't Eat Mayonnaise Department:

A major mayonnaise manufacturer refused to buy commercial time based upon the perception that "Black people don't eat mayonnaise." (National Association of Black Owned Broadcasters, Spring Conference, 1997, page 2 of report)

It's a lie! (Sorry, Undercover Brother.)

I saw a mayo commercial this weekend featuring a black family (Well, a mother and a child. No father to be seen... Come to think of it, that is a black family these days.) and marketing is never wrong.