Pasteurization and Sterilization of Milk by Supercritical Carbon Dioxide Treatment

摘要

Supercritical (SC) CO_2 treatment of row skim milk was studied in order to improve the shelf-life while maintaining its nutritional and organoleptic properties. To this purpose, experimental laboratory tests were made and an optimal set of operating process parameters were found. In fact, at P = 150 bar, 35°C ≤ T < 40°C, and CO_2/Milk feed ratio equal to 0.33, the treatment is significantly more efficient than the traditional thermal pasteurization (HTST technology, at 75÷80°C for 15÷20 s) made in continuous mode by using a proper thermal exchanger system. Finally, a new process for the SC CO_2 mild pasteurization of whole milk at industrial scale was described and discussed.