ANTIMICROBIAL EFFECT OF PRESSURIZED CARBON-DIOXIDE ON LISTERIA-MONOCYTOGENES

Listeria monocytogenes was inactivated by carbon dioxide at 35 and 45 degrees C under pressures of 70.3 and 210.9 mu g/cm(2). Inactivation rates were sensitive to temperature and pressure. Other factors such as pH, moisture content, and environmental conditions of cell growth also influenced the effectiveness of CO2 treatment. Bacteria were more difficult to inactivate when they were suspended in the medium with fat or oil, which may have protected the cells from penetration by CO2. Fat in growth medium where Listeria monocytogenes cells were inoculated apparantly increased their resistance. Several methods may be useful for increasing inactivation rates.