High pressure (HP) processing is an innovative process for food preservation mainly due the inactivation that pressure induces in microorganisms and/or enzymes. The correct design and optimization of HP processes requires knowledge of the volumetric properties of the foods and pressure fluids implicated in those processes. In this study, a cell capable of measuring volume variations caused by pressure and/or temperature changes has been employed to determine the specific volume of tomato paste from 0.1 MPa to 350 MPa and in a temperature range from 273.16 K to 323.16 K(0 degrees C to 50 degrees C). From these values an empirical equation for the specific volume and the isothermal compressibilities of tomato paste, as a function of pressure and temperature, were also determined. (C) 2010 Elsevier Ltd. All rights reserved.