other gray meat

Does someone know the origin of the word "other gray meat?", meaning brain, pork, or strange meat(like organs of animals or possums, rats...etc ) ?
Did it originate from the Zombie movies?

I can start the meat ball rolling by saying the pork people have an ad campaign -- the other white meat. www.theotherwhitemeat.com/

I have no answer, but for what it's worth I searched on both spellings (grey and gray) and found that it's the slogan on zombie.com's "flagship" t-shirt. There is no movie with this quote on IMDB.com. I suspect it's a cooking term which was imported into zombie lore, rather than the other way around. Pamela