CFD simulation for the pasteurization of fruit puree with pieces

Thermal pasteurization is a technique widely utilized in the industry to reduce the microbial content of foods and increase their shelf life. The food pasteurization is commonly carried out in continuous process where the food undergoes to a rapid heating and a subsequent cooling with high heat transfer coefficients in order to reduce the degradation of main constituents like proteins and vitamins, and keeping almost unchanged the food organoleptic properties. Continuous pasteurization processes are commonly used to treat creams, tomato sauce, fruit juice, as well as products with solid particles or pieces like soups or baby foods. In such cases, the presence of dispersed large particles in the fluid can causes issues in the correct process setup. Indeed, the process setup must assure the pasteurization condition in the overall product food, included the centre of the particles. Here the heat penetrates by conduction and usually it becomes the actual limiting step of the process. In this work we estimate the pasteurization condition for a pilot scale pasteurization process for the thermal treatment of pear puree with pieces by the use of the Computational Fluid Dynamic approach. The results show that the heat penetration resistance into the solid particle reduces of about 32% the microbial abatement in the particle centre; however the P85 value results always higher than the minimum required for the food pasteurization. Copyright © 2014, AIDIC Servizi S.r.l.