This standard specifies a reference method for the determination of the copper content of milk and milk products. The method is applicable to: a) milk, skimmed milk and buttermilk, b) evaporated milk and sweetened condensed milk, c) whole and skimmed milk powder, d) cream and butter, e) butterfat, f) ice-cream, g) hard, semi-hard and soft cheeses of various ages, and processed cheese and h) caseins, caseinates and coprecipitates. The method is suitable to determine copper contents as low as 0,05 mg/kg in test samples of butter and butterfat.