A model simulating the thermal behaviour of a solid-liquid food mixture flowing in an ohmic heating sterilizer is presented. It is based on the principle of a mean slip Velocity between the two phases in plug flow. Local electrical heat generation, convective heat transfers and heat conduction within the solid particles are taken into account. A qualitative study of the effects of slip velocity, delivery volume fraction, particle size and electrical conductivity is then performed. The importance of the particle internal temperature gradient is therefore shown.