Mathematical equations for modeling immersion chilling and freezing of foods were developed. Solid foods were assumed as a porous media with an occluded solution. Three phases were considered, the rigid solid matrix, the liquid phase, and the ice phase. Transport equations for a continuous media were applied to each phase. The averaging-volume method developed by Whitaker [Adv. Heat Transfer 13 (1977) 119] was used for obtaining comprehensive equations to predict solute concentration and temperature as a function of space and time. The thermodynamic relation between temperature and solute concentration in presence of ice is critical to complete the mathematical formulation. Moreover, the thermal properties and enthalpy depend on the initial depression of freezing point. This work contributes with a simple model for predicting heat and mass transfer phenomena during immersion chilling and freezing of foods. (C) 2004 Elsevier Ltd. All rights reserved.