The combined effect of supercritical carbon dioxide (SC-CO2) and high power ultrasound (HPU) on the inactivation kinetics of Escherichia coli, Saccharomyces cerevisiae and pectin-methyl esterase (PME) in orange juice was studied in order to select models that can predict their inactivation behaviour based on process parameters. Experiments were performed at different temperatures (31-41 degrees C, 225 bar) and pressures (100-350 bar, 36 degrees C). The inactivation rate of E. coli, S. cerevisiae and PME increased with pressure and temperature during SC-CO2 + HPU treatments. The SC-CO2 + HPU inactivation kinetics of E. coli, S. cerevisiae and PME were represented by models that included temperature, pressure and treatment time as variables, based on the Biphasic, the Peleg Type B, and the fractional models, respectively. The HPU-assisted SC-CO2 batch system permits the use of mild process conditions and treatment times that can be even shorter than those of continuous SC-CO2 systems. (C) 2014 Elsevier B.V. All rights reserved.