A reliable, quick and userfriendly method for thermal diffusivity estimation has been developed. An appropriate software tool, based on least square optimization of a finite difference solution of Fourier's equation, has been created and an appropriate measuring cell has been designed and made in order to decrease the systematic error in probe positioning. The method has been experimentally validated and its results have been compared with those obtained by three other available methods. Several foods (tomato products, low-acid pasta sauces, olive pate, confectioner's custard and apricot jam) were tested and in every case the method proved to be effective. The developed software also allowed estimation of thermal diffusivity via heat penetration curves obtained by variable temperature treatments. So it has been also possible to exclude the contribution of container material from the estimation of thermal diffusivity of liquid packed foods. The proposed method turns out to be a useful tool for scientific design of several processes, such as sterilization and pasteurization, and for correct control of transport, storage and distribution of foods. (C) 2008 Elsevier Ltd. All rights reserved.