Melamine is a common industrial chemical contaminant which should be absent from food and feed supplies due to melamine's toxicity. Provided is a method to assess the presence of melamine in samples prepared from compositions. The method may include using a microbial enzyme called melamine deaminase which hydrolyzes melamine to ammeline and ammonia. The method may include assessing the presence of any ammonia produced from an enzymatic reaction between the sample and the enzyme.