Inactivation of microorganisms naturally present in raw bovine milk by high-pressure carbon dioxide.

This study assessed the inactivation of microorganisms naturally present in raw bovine milk by high-pressure carbon dioxide (HPCD) at 10-30 MPa and 20-50 °C for 20-70 min. The log reduction of microorganisms increased as raw bovine milk was exposed to higher pressures and temperatures and longer treatment times. The maximum reduction of aerobic bacteria (AB) was 4.96-log at 25 MPa and 50 °C for 70 min. At lower temperatures and treatment times, a complete inactivation of yeasts and moulds (Y&M) and coliform bacteria (CB) was obtained at 25 MPa. Changes in microorganisms naturally present in raw bovine milk during storage were also assessed. There were 1.83-log survival of AB, 0.65-log survival of Y&M and a complete inactivation of CB in raw bovine milk when subjected to HPCD at 25 MPa and 40 °C for 50 min. Moreover, the AB, Y&M and the CB in raw bovine milk exhibited insignificant alterations during storage at 4 °C for 15 days, indicating a potential capability of HPCD to extend the shelf life of milk. [ABSTRACT FROM AUTHOR]