A multi-batch apparatus was developed for investigating food inactivation by high-pressure CO2, both for performing preliminary studies on CO2-substrate interactions and for measuring the inactivation kinetics of the microorganisms suspended in food matrices. Experiments were carried out for inoculated liquid growth medium and fruit juices, using the yeasts Saccharomyces cerevisiae ATCC 9763 and Pichia awry wild type as test microorganisms. Different combinations of temperature (38 and 32 degrees C), pressure (90 and 75 bar) and treatment time were investigated. The logarithmic inactivation kinetic curves showed a quite linear behavior with a slope change in some cases. It was also shown that the pasteurization degree of the considered foodstuffs depends on the physical-chemical properties of the treated substrate. The proposed multi-reactors system allows to save both working time and materials, giving a better collection of experimental data in terms of reliability and homogeneity. (c) 2006 Elsevier B.V. All rights reserved.