Antimicrobial effects of pressurised carbon dioxide on Brochothrix thermosphacta in broth and foods

Antimicrobial effects of high-pressure CO2 on Brochothrix thermosphacta wer e investigated in a batch system. Inactivation rates increased with increas ing pressure, temperature and exposure time. B thermosphacta suspended in p hysiological saline was completely inactivated under 6.05, 3.02 and 1.51 MP aCO2 treatment at 35 degrees C after 10, 25 and 50 min respectively. Two ph ases were observed in the survival curves. The earlier stage was characteri sed by a slow rate of decrease in the number of B thermosphacta, which incr eased sharply at the later stage. B thermosphacta suspended in brain heart infusion broth was completely inactivated under 6.05 MPaCO2 treatment after 80, 50 and 30 min at 25, 35 and 45 degrees C respectively. About 6.90 and 5.93log cycles of B thermosphacta were reduced under 6.05 MPaCO2 pressure a t 45 degrees C in whole and skimmed milk respectively. The sterilisation ef fects of 6.05 MPaCO2 pressure at 45 degrees C on both B thermosphacta and a erobic plate count were observed after 150 and 120 min respectively in skin ned meat. (C) 2000 Society of Chemical Industry.