This International Standard specifies a reference method for the determination of the freezing point of raw bovine milk, heat-treated whole, reduced fat and skimmed bovine milk, as well as raw ovine and caprine milk, by using a thermistor cryoscope. The freezing point can be used to estimate the proportion of extraneous water in milk. Calculation of the amount of extraneous water is subject to daily and seasonal variations, 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 are not representative of the original milk. NOTE 1 Sterilization and vacuum pasteurization can affect the freezing point of milk (see Reference [5]). NOTE 2 The method uses plateau-timed instruments. For routine measurements, other thermistor cryoscope methods, i.e. fixed time procedures, can be used. Guidelines for the application of other procedures are given in Annex C. NOTE 3 The limit value mentioned for the titratable acidity in Clause 1 and 9.2 applies to bovine milk. It is possible that the limit values for ovine and caprine milk are higher.