Three months ago, my father aged 74 who has never reacted to anything - plant, animal or food - had a major reaction of a welt like rash on the trunk especially in the groin area and under arms. It was enough to go to the doctor who simply dismissed this as hives and prescribed steroid tables with no real explanation of what had happened. His wife thought there must be a connection as it was half an hour after eating a packet pizza containing 635 that they hadn't eaten before. A similar incident then happened about a week later, after eating [a ‘healthy’ prepared frozen dinner also containing 635] for the first time. Now they avoid such packaged food and he has not experienced it since, although he has often eaten in restaurants with no ill effects. – by email from NSW