Do you have a Jewish bakery nearby? There is an excellent one in Denver, sadly 30 miles from where I live, and all their products (bagels, hot dog buns, etc.) are corn free.
I'm not Jewish, so I can't explain Kosher requirements, but I have found most Kosher foods are corn free. I love the mom and pop bakeries,...they are so accommodating, and I just love supporting a small business.
Good luck finding an alternative!
Elaine