Romanian Biotechnological Letters Vol. 18, No. 5, 2013 Copyright © 2013 University of Bucharest Printed in Romania. All rights reserved ORIGINAL PAPER   Romanian Biotechnological Letters, Vol. 18, No. 5, 2013 8573 Aspergillus ochraceus spores inactivation with high-pressure carbon dioxide Received for publication, June 5, 2013 Accepted, August 26, 2013 CORINA NEAGU 1 , DANIELA BORDA 1* AND OSMAN ERKMEN 2 1 “Dunărea de Jos” University of Galaţi, Faculty of Food Science and Engineering, 111 Domneasca, 800201, Galati, Romania 2 Department of Food Engineering, Faculty of Engineering, University of Gaziantep, 27310 Gaziantep Turkey *Address correspondence to: Dunarea de Jos University of Galaţi, Faculty of Food Science and Engineering, 111 Domneasca, 800201, Galati, Romania Tel.: +40336130177; Fax: +4023646016; Email: daniela.borda@ugal.ro Abstract The aim of this research was to study the inactivation of Aspergillus ochraceus spores exposed to high pressure carbon dioxide (HPCD) treatments and to estimate the kinetic and the thermodynamic parameters. A synergistic effect of pressure and temperature was noticed in the range from 5.4 to 7 MPa and from 30 to 50°C. Weibull model is the best primary kinetic model to describe the inactivation of A. ochraceus in the range from 5.4 to 7 MPa and from 30 to 50°C. The statistical indices show better correlations between the experimental and the predicted values for Weibull equation compared with Gompertz and Logistic models. The values of enthalpy, enthropy and total free energy were estimated for the experimental domain using nonlinear regression analysis. There was no significant variation in the values of the Gibbs free energy for the experimental domain. This work contributes to the general understanding of mould inactivation using high pressure carbon dioxide (HPCD) treatment. Keywords: supercritical carbon dioxide, inactivation, mould, kinetics, thermodynamics. 1. Introduction The increasing consumers demand for natural, fresh food, free of chemical preservatives, and the current trends to avoid over-processing the foods which may produce a loss of flavor, color and nutrients, have led the food industry to developing an interest in non- thermal processing (C. ORTUŇO & al., 2012 [1]). In the last two decades, applications of high pressure carbon dioxide (HPCD) using either sub- or supercritical CO 2 emerged as promising for pasteurization of foods (L. GARCIA-GONZALEZ & al., 2009 [2]). This process effectively inactivates vegetative microorganisms and, because a low temperature can be applied, HPCD processing can produce high-quality, pasteurized food products, meeting the consumer’s expectations (L. GARCIA-GONZALEZ & al., 2007 [3]). Supercritical carbon dioxide (SC-CO 2 ) has a liquid-like density, gas-like diffusivity and viscosity, and a zero surface tension. It is, therefore, capable of penetrating into complex structures, and has the ability to inactivate microorganisms (C. ORTUŇO & al., 2012 [1]). Numerous microbial strains have been studied in order to evaluate their sensitivity to HPCD treatments. The species that have been investigated ranged from Gram-negative bacteria like Salmonella typhimurium, Escherichia coli or Yersinia enterocolitica to Gram positive or yeasts, such as S. cerevisiae, L. innocua or L. monocytogenes. However, until now less work was reported for moulds (M. SHIMODA & al., 2002 [4]), although the total microbial flora inactivation by HPCD was reported (G. FERRENTINO & al., 2013 [5]). Fungal contamination is one of the main sources of pre- and post harvest grains deterioration. Members of the Aspergillus spp., amongst many other toxigenic fungi, have