Freezing point of milk

The freezing point of bovine milk is usually in the range —0.512 to — 0.550°C, with a mean value close to — 0.522°C (Sherbon, 1988) or -0.540°C (Jenness and Patton, 1959). Despite variations in the concentrations of individual solutes, the freezing point depression of milk is quite constant since it is proportional to the osmotic pressure of milk (approximately 700 kPa at 20°C), which is regulated by that of the cow s blood. The freezing point of milk is more closely related to the osmotic pressure of mammary venous blood than to that of blood from the jugular vein. 

The freezing point of milk, like that of any aqueous system, depends on the concentration of water-soluble components. The mathematical relationship between depression of the freezing point and concentration of the solute was determined by Raoult (1884) and is expressed in the equation... 

Demott, B. J. 1966. The freezing point of milk produced in four markets in Tennessee. Milk Food Technol 29, 319-322. 

Demott, B. J., Hinton, S. A. and Montgomery, N. J. 1967. Influence of some management practices and season upon freezing point of milk. J. Dairy Sci. SO, 151-154. 

Evans, E. W. and Johnson, V. W. 1978. Effect on the freezing point of milk of restricting and providing water to the cow. Proc. 20th Int. Dairy Congr. E., pp. 212-213. 

Henderson, J. L. 1963. The effect of handling and processing on the freezing point of milk. J. Assoc. Offic. Agr. Chem. 46, 1030-1035. 

Henningson, R. W. 1967. Determination of the freezing point of milk by thermistor cryoscopy. J. Assoc. Offic. Anal. Chem. 50, 533-537. 

Mussenden, S., Hodges, J. and Hiley, P. G. 1977. Sodium and chloride in cows drinking water and freezing point of milk. J. Dairy Sci. 60, 1554-1558. 

Schoenemann, D. R., Finnegan, E. J. and Sheuring, J. J. 1964. Statistical analysis of the freezing point of milk and associated factors in surveys of Florida and Georgia milk. J. Dairy Sci. 47, 683. 

Temple, P. L. 1937. A new apparatus for the rapid and economical determination of the freezing-point of milk. Analyst 62, 709-712. 

The freezing point of milk is —0.53 to —0.55 °C. This rather constant value is a suitable test for detection of watering of milk. 

Various dairy products such as fluid and concentrated milk may be preserved by freezing. Milk has a lower freezing point than water due to dissolved constituents such as lactose and salts. The average freezing point of milk is 31 F (-0.54°C). 

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