I was initially diagnosed with histamine intolerance in 2010 by a histamine plasma and diamine oxidase test. (healinghistamine.com)
Therefore, the intake of drugs, especially long - term medication, should be considered in interpretation of histamine intolerance symptoms and DAO concentrations. (academic.oup.com)
Beef often is not extremely fresh, because the convention is to hang beef for at least a couple of weeks before it is cut for sale in order to tenderize it, so if you have issues with biogenic amines, this can be a second possible reason why beef can bother some people (please see my post about Histamine Intolerance). (diagnosisdiet.com)