Combining High-Pressure Processing and Supercritical Carbon Dioxide for Inactivation of .

The effect of high-pressure treatment with supercritical CO on the inactivation of in a fish soup was investigated. The soup was inoculated with , packaged in modified atmosphere with 50:50 or 95:5 CO:N, high-pressure processed (300, 350, 400 and 600 MPa, 2 min) under subcritical (T < 304 K) or supercritical conditions (T > 304 K) and stored at 4 °C for up to 53 days. Treatment at 400 and 600 MPa had a significant ( < 0.05) effect on under both supercritical and subcritical conditions. In contrast, pressurization at 350 MPa and supercritical conditions were needed to significantly ( < 0.05) inactive . Increased levels of CO in the headspace significantly ( < 0.05) reduced the bacterial load during processing, and supercritical conditions had a significant ( < 0.01) interaction with both CO levels and pressure. Increased storage time gave significantly increased levels of at 400 and 600 MPa. In addition, high levels of CO significantly decreased ( < 0.001) growth. However, 350 MPa under supercritical conditions seemed to set the in a permanent lag phase, with slow and steadily decreasing numbers of bacteria during storage. All the design variables resulted in significant inactivation of , and supercritical conditions combined with high levels of CO inhibited the recovery of to a large degree.