The same thing happened to me. I painstakingly went through every single combination possible (I even wrote them down to be sure I didn't miss one) and I have 17 as well.

I read somewhere about a death stew, but I didn't get that one. I was scared everytime I had one of my villagers taste a green smoke stew for fear they would die but no one did.

Maybe there's something extra you could add to the stew that we didn't think of? Or hasn't been discovered yet? I'd hate to have to go back through the whole list to see if I mesed up the ingredients of one.