Yosef Karo, Shulchan Aruch — Yoreh Deah 117 To not make commerce from a forbidden thing
“ Anything that is specifically for eating and Biblically prohibited, even though it is not forbidden to derive benefit from it, is forbidden to do business in it. Rema: Or to lend with it as collateral. And even to purchase it to feed it to one’s idol worshipping workers is forbidden. ”
