Eloys, how did you do preservatives? I really think preservatives have a bit to do with it too. He can eat homemade bread and cooked ham and get no red bottom. He eats the same thing at Subway or E&G, and he gets a red bottom. I have looked at the chemicals in the bread/foods. There are sooooo many, that you would have no idea how to pinpoint which one(s) are problematic. Same thing actually happens with a McDonalds hamburger. The thing in common? Processed bread... I have thought back to him getting the double ring rash from the total cereal bars I made when we were doing dairy/soy free. It could be the molasses (which seems to be a coinciding flare up ingredient I avoid now), but Total cereal has lots of additives for vitamins. It probably has the most additives out there. So, the reason that gave such a reaction (from several bites) may be additives or molasses.
I am thinking that the berries and grapes flare the reflux angle, and preservatives may be flaring the bottom issue? That is how it seems to be panning out here. Of course, when ever I think we are pinning something down, it turns out to something else.