We have reported that the inactivation effect of carbonation with heating (CH; 80°C, 5 MPa, 30 min) on Bacillus subtilis spores was enhanced by the addition of monoglycerol-caprate (MC₁₀). The aim of this study was to obtaine aspects of the mechanism of this enhanced inactivation. The addition of MC₁₀ (0.05%) to spores suspended in nutrient broth (NB) at pH 3.2 increased the inactivation of spores by heating (HT, 80°C) alone and with pressurization (5 MPa nitrogen gas). However, no inactivation effect was observed in NB at pH 6.8. The results showed that MC₁₀ increased the number of spores with decreased resistance to heat and pressure under acidic conditions. The addition of MC₁₀ also enhanced the ratio of spores germinated by CH. The bacteriostatic effect of MC₁₀ was enhanced when combined with CH. This enhanced bacteriostatic effect might be responsible for inducing the high inactivation effect of CH with MC₁₀.