The only buns I've ever found that are safe for pn, tn, egg and sesame are from In N Out Burger. Sometimes they are willing to sell me a package. They aren't in too many places, but it's an idea if you happen to have one. It depends on which manager is working, but sometimes they are very nice. Price varies. One time they just gave them to me, but I usually pay $2 PER BUN!