ABSTRACT
High-pressure
CO2 treatment has been studied as a promising method for
inactivating bacterial spores. In the present study, we compared this
method with other sterilization techniques, including heat and pressure
treatment. Spores of Bacillus coagulans, Bacillus
subtilis, Bacillus cereus, Bacillus
licheniformis, and Geobacillus stearothermophilus were
subjected to CO2 treatment at 30 MPa and 35°C, to
high-hydrostatic-pressure treatment at 200 MPa and 65°C, or to
heat treatment at 0.1 MPa and 85°C. All of the bacterial spores
except the G. stearothermophilus spores were easily
inactivated by the heat treatment. The highly heat- and
pressure-resistant spores of G. stearothermophilus were not
the most resistant to CO2 treatment. We also investigated
the influence of temperature on CO2 inactivation of G.
stearothermophilus. Treatment with CO2 and 30 MPa of
pressure at 95°C for 120 min resulted in 5-log-order spore
inactivation, whereas heat treatment at 95°C for
120 min and high-hydrostatic-pressure treatment at 30 MPa and
95°C for 120 min had little effect. The activation energy
required for CO2 treatment of G. stearothermophilus
spores was lower than the activation energy for heat or pressure
treatment. Although heat was not necessary for inactivationby CO2 treatment of G. stearothermophilus spores,
CO2 treatment at 95°C was more effective than
treatment at 95°C
alone.
Germination and inactivation of Bacillus coagulans and Alicyclobacillus acidoterrestris spores by high hydrostatic pressure treatment in buffer and tomato sauce
