I know what you mean about something putting you off of a food, it's happened to me a few times.
Once with KFC I found what I thought at the time was a kentucky fried worm (although it was probably just a piece of skin)...I couldn't even drive past a KFC without gagging for years.
Another time my mother mentioned she found a flour beetle on a store bought cookie. That put me off of store bought cookies for about six months.
To get off of chocolate maybe read one of the many web articles about the child slavery issue apparently associated with it. Although personally I don't know if anything could stop me eating chocolate.
Being a food addict myself though really the issue is getting down to why you crave certain things. Once you get past the issue that maybe it's your body screaming for a certain type of thing (i.e. sodium, iron, etc.) for physical reasons then it's usually an emotional/psychological reason. Myself, I'm still trying to work out the exact reason and since I can't afford an expensive therapist I've started an online journal that will hopefully help me figure it out.
Good luck to you.
Sue
Diary of a Fat White Woman - My Struggles with Food Addiction