I don't know too much about BPA, but I recall hearing something about it depending on the type of container, how much is potentially in it. A completely clear plastic container is going to have higher amounts, than a cloudy plastic one. Also, when this was big news awhile back with the baby bottles, I read something about the bpa being leeched into the milk or formula in greater amounts during the heating process.
I don't think you should worry about feeding him too many canned fruits and veggies (although some cans also have tested positive for BPA)--it's great that he loves them so much! However, anything pre-made has so many less nutrients than something fresh, or that you steam or bake yourself. Is it possible for you to make big batches of baked or steamed veggies or fruit (if they're too hard to eat raw), and freeze them for future use? He'll get a lot more out of them (nutritionally), and they'll probably taste a lot beter too.
Also, then you can find BPA free containers, and you won't have that to worry about.