A method for detection of wheat, rye, barley and oat proteins in a wide range of foods, including baked goods and processed meats has been developed. The procedure requires immobilisation of food extracts upon nitrocellulose paper followed by treatment with an enzyme-conjugated monoclonal antibody. Upon addition of the appropriate enzyme substrate, gluten-containing foods yield purple spots; a wide range of non-gluten common food proteins did not react. The method has several advantages over other means of detecting cereal protein, such as electrophoresis. It is rapid, requiring little sample preparation, and does not require sophisticated equipment or prior knowledge of electrophoretic patterns of common non-cereal food proteins. Since the method may be used with cooked or baked foods, it should be suitable for food-monitoring applications.