<<Disclaimer: Verify this information before applying it to your situation.>>
 
Are you checking the labels on the canned vegetables?  Some of
them add flour (wheat) to thicken the liquid.
 
In what form is the rice?  If it is plain brown or white rice,
there shouldn't be a gluten problem.  However, rice cereals and
rice crackers may use glutinous products (i.e., barley malt).
 
And, yes, crumbs can cause lots of problems.  Just recently, I
went through a week of diarrhea and stomach pain after taking
just one vitamin E capsule (made with wheat germ oil).
 
Hope you find the culprit.
 
                                BJ