The link below takes you to a page with a few diagrams showing feral hog scent glands.  The preputial gland is connected to the urethra in the penis and the metacarpal gland is on the bottom side of the front legs near the feet (see diagrams).  If you stay away from the glands all together when cleaning the animal or butchering it, you should reduce the chance of contamination. Wear gloves and don't touch the glands with your hands or knife when handling the the animal. 

http://www.extension.org/pages/64381/feral-hog-behavior#.Uf_5UNKkpm4