I have coeliac (celiac) disease, ingestion of various cereal proteins (in wheat, barley, rye; thankfully not oats for me) cause an exciting array of gastrointes

I have coeliac (celiac) disease, ingestion of various cereal proteins (in wheat, barley, rye; thankfully not oats for me) cause an exciting array of gastrointestinal phenomena. A visual inspection is usually enough to tell me about low-level contamination. Recurring or high level ingestion becomes fairly evident to anyone within earshot, and effects usually last more than a week :/