Observed freezing point and milk solids-not-fat values were determined for approximately 400 retail samples. Most of these samples were systematically collected at monthly intervals over a calendar year from designated processing plants.
The average observed freezing point value found was −0.529°C. The average MSNF value found was 8.88%. No relationship was expected, or found, between the observed freezing point value and the MSNF value of milks. The MSNF value did not assist in explaining high freezing point values or in confirming the presence of added water. It did prevent suspicion which could not be easily confirmed.
A minimum freezing point depression standard, based on area data and administered in a manner similar to a minimum butterfat standard, appears to be the most feasible way of utilizing the cryoscopic method for the determination of added water in milk.
Determination of the ionization constant of weak carboxylic acids via freezing point depression measurements
