They add it to most dried foods for color and preserving them and they don't have to put it on the label. I think they should have to list everything they put in their product. I read recently that they want to add Nutrasweet to milk and not have to list it in the ingredients...I've given up Nutrasweet and all the artificial sweeteners because of how crazy they seem to make my appetite. It would not be cool to buy a product that had that in it and not know about it...Sulpher dioxide? I have never seen it listed on dehydrated tomatoes. If it had had much sulfur dioxide I would have reacted big time. It is a pain in the a$$ being allergic to half the world.