Milk freezing point
Pure water freezes at 0 °C. When solutes are added to water the freezing point is depressed. The freezing point of milk varies between –o.52 and -0.56 °C. Any variation over -0.525 ° C indicate watering.
The selection of -0.0525 °C as the upper limit is based on the statistical evaluation of data from 1968 North American survey of the freezing point of authentic samples.
The freezing point of milk is lower than that of pure water due to dissolved components. This property is measured to determine whether the milk has been diluted with water and is employed as a legal standard. This make it possible to detect milk watering from 3%.
A drop in the freezing point can also be caused by the subdivision of the lactose into many smaller molecules. Other than lactose chloride also the major contributors to the freezing points of milk.
The freezing point of milk is its most constant physical property. The secretary process of the mammary gland is such that the osmotic pressure is kept in equilibrium with blood and milk.
