This International Standard specifies a reference method for the determination of the freezing point of raw, pasteurized, UHT-treated or sterilized whole milk, partially skimmed milk and skimmed milk by using a thermistor cryoscope. The freezing point can be used for estimating the proportion of extraneous water in milk. Calculation of the amount of extraneous water is complicated by daily variation, seasonal variation, etc. and is not within the scope of this International Standard. Results obtained from samples with a titratable acidity exceeding 20 ml of 0,1 mol/l sodium hydroxide solution per 10 g of non-fat solids will not be representative of the original milk. NOTE Sterilization and vacuum pasteurization can affect the freezing point of milk (see reference [6]).