I use the same stuff or food grade silicone grease for the spot where the worm presses on the bushing. You can buy the food grade silicone spray lube from cabela's too. Just be sure to wash off whatever you use before using your grinder.
I just use a light coating of Pam also. So far no problems. I do kinda worry about it getting rancid, so I always wash every thing off before I start a session. I made some storage sleeves out of foam packing material, then store them in zip lock bags. I think I posted this just before the big crash and it got lost.