I know I became allergic (acquired allergy) to a preservative that is found in many foods. I got it from eating processed foods, fast foods for 20 years after I got the kids mostly out of the house.
I have reflux triggered when I eat anything with sulfite preservative in it. Notable examples are french fries, sodas and lemon juice. Now that I've had surgery I can't reflux into my esophagus any more, but I still have the stomach heaving. It al ends up causing me to have tachycardia. Another common symptom of this particular allergy is migrane headache.
I've done extensive logging of my foods in a journal and have done lots of "chalenge testing," and consulted with an allergist, so I know my problem. Dollars to doughnuts I'm not the only person who has GERD triggers from chemicals in food.
(Milk lasts longer primarily because of "ultra pasteurization" but bread has chemical additives. Remember when the loaf lasted 3 days on the shelf?