<<Disclaimer: Verify this information before applying it to your situation.>>

I once got marvelous advice from a naturopath when we were trying to
figure out what was giving my daughter hives.  I had fed her Perdue
chicken and by the time it hit her stomach, she had broken out.
HIS ADVICE:  first, try an organic form of the food to see if you are
allergic to it...or what was fed to it or sprayed onto it. If you have
no reaction to the roganic, try another brand or form of the food...
It was good advice and helped me get a handle on it.