This standard specifies the requirements, test methods, signs, packaging, storage and transportation of feed grade DL and methionine products. This standard is applicable to feed grade DL-methionine chemical formula: CH3S-CH2-CH< Subscript 2>-CH (NH3)-COOH Relative molecular mass: 149.2 (according to the international relative quantity in 1995) Chemical name: 2-amino-4-methylthiobutyric acid