Automatic milking systems in the Protected Designation of Origin Montasio cheese production chain: Effects on milk and cheese quality

摘要

Montasio cheese is a typical Italian semi-hard, semi-cooked cheese produced in northeastern Italy from unpasteurized (raw or thermised) cow milk. The Protected Designation of Origin label regulations for Montasio cheese require that local milk be used from twice-daily milking. The number of farms milking with automatic milking systems (AMS) has increased rapidly in the last few years in the Montasio production area. The objective of this study was to evaluate the effects of a variation in milking frequency, associated with the adoption of an automatic milking system, on milk quality and on the specific characteristics of Montasio cheese. Fourteen farms were chosen, all located in the Montasio production area, with an average herd size of 60 (Simmental, Holstein-Friesian, and Brown Swiss breeds). In 7 experimental farms, the cows were milked 3 times per day with an AMS, whereas in the other 7 control farms, cows were milked twice daily in conventional milking parlors (CMP). The study showed that the main components, the hygienic quality, and the cheese-making features of milk were not affected by the milking system adopted. In fact, the control and experimental milks did not reveal a statistically significant difference in fat, protein, and lactose contents; in the casein index; or in the HPLC profiles of casein and whey protein fractions. Milk from farms that used an AMS always showed somatic cell counts and total bacterial counts below the legal limits imposed by European Union regulations for raw milk. Finally, bulk milk clotting characteristics (clotting time, curd firmness, and time to curd firmness of 20 mm) did not differ between milk from AMS and milk from CMP. Montasio cheese was made from milk collected from the 2 groups of farms milking either with AMS or with CMP. Three different cheese-making trials were performed during the year at different times. As expected, considering the results of the milk analysis, the moisture, fat, and protein contents of the experimental and control cheeses were comparable. The milking system was not seen to significantly affect the biochemical processes associated with ripening. In fact, all cheeses showed a normal proteolysis trend and a characteristic volatile compound profile during aging. Therefore, the milking system does not appear to modify the distinctive characteristics of this cheese that remain dependent on the area and methodology of production.