Influence of pressurized carbon dioxide on the thermal inactivation of bacterial and fungal spores

Abstract

The antimicrobial potential of CO2 applied under 5 M Pa pressure during heat treatment was investigated against Bacillus subtills spores, Byssochlamys fulva ascospores and Aspergillus niger conidia. The rates of thermal inactivation were increased in the presence of pressurized CO2 when treatment was carried out at a temperature higher than a threshold value depending on the tested microorganism (80 °C for B. subtilis and B. fulva, 50 °C for A. niger). The antimicrobial effectiveness of CO2 varied with the microorganisms, the temperature and the aw of the suspension medium. However, the increase in the destruction rate was relatively more extensive when the temperature was sublethal or low lethal. At elevated lethal temperatures, the antimicrobial effect of pressurized CO2 disappeared. Moreover, a low aw antagonized the lethal effect of CO2 under pressure. © 1998 Academic Press Limited.