...container or do we need a new one? We have a plastic food storage container to keep the food fresh that we paid quite a bit for and also a "self-feeder" for her (the dog) to use, but we don't want to contaminate the new food with gluten as we are dealing with the switch for a child who has celiac disease and the contamination can be deadly.

yea definately because food particles no matter how small can be transferred so easily by hand. just like germs, we dont see them but their there, and our hands are the transporters. I suggest you wash/clean the surrounding bedding, and area coz they may have traces of this also. its better to sacrifice a bit of time and money for the sake of a childs life. hope this helps