In order to find the relationships among variables affecting the resistance of salmonella to the thermosonication treatment, the combined effect of simultaneously applied ultrasonic waves and heat treatment on the survival of a strain of Salmonella enterica serovar Enteritidis was studied in several volumes (100, 200, 500, 750 and 1200 mL) of distilled water. The higher the liquid volume, the greater the decimal reduction times (D(R)). The joint confidence regions for D(R) and z were calculated showing significant (p < 0.05) differences for the different treated volumes. The influence of the applied ultrasonic power on the kinetic constants was modelled using a logarithmic equation. The sonication of whole eggs provided kinetic constants in agreement with the logarithmic model found. A model was developed to integrate all the variables (temperature, time and ultrasonic power), attaining a close fit of the experimental data (R(2) = 0.95). This model allows the effect of sonication to be predicted under different process conditions and, therefore, is useful for the scale-up of the system. (C) 2009 Elsevier Ltd. All rights reserved.