Seasonality of sheep milk freezing point and relationship with other chemical and physical milk parameters

Milk freezing point (FP) is an important quality indicator which can be used for determination of possible adulteration of the milk with water. The aim of this study was to evaluate the influence of seasonality on ewe FP produced in Sicily during the last 10 years of investigation. A total of 1,996 samples of raw bulk ewes’ milk were collected from 295 dairy factories located in western Sicily (Italy). The average of the FP during the entire period of investigations was -0.560 °C ± 0.013 °C. The seasonality of milk FP showed that at the beginning of lactations (September) the FP was -0.554°C, than it decreased up to December (-0.561°C). Successively, FP increases until the end of lactations were the lowest values were recorded in August (-0.551°C). The Pearson correlation analysis showed a significant negative correlation between FP and milk fat percentage (r= -0.21), milk protein content (r= -0.23), milk urea content (r= -0.30), milk lactose percentage (r= -0.25) and titratable acidity (r=-0.27) that demonstrate a strong correlation between milk FP and milk chemical composition.