This International Standard specifies a method for the quantitative determination of the total sterols content by means of an enzymatic staining test. The method is applicable to free and esterified sterols in animal and vegetable fats and oils, fatty foods and related products. The determination is applicable to sample quantities of 1 g to 2 g of fat. The method is not applicable to dark coloured fats and oils. The enzyme is not specific for cholesterol, but also oxidizes other 3-hydroxysterols. The method has not been tested for products fortified with sterols at higher levels. Milk and milk products (or fat coming from milk and milk products) are excluded from the scope of this International Standard. NOTE The method is technically equivalent to IUPAC method 2.404[8] and DGF standard method F-III 2 (91).[7]