Hi,
Our son did the same thing with food and, at 27, he still has contamination phobias. Expirations are always focused on. He calls us up with questions, like whether or not his canned food should have "that color" or not. I believe it's par for the course of raising this type of high IQ child. My empathy! It gets better when they're adults. They can control themselves better and find their niche in careers and are happier.

-San