OPTIMUM STERILIZATION: A COMPARATIVE STUDY BETWEEN AVERAGE and SURFACE QUALITY

Abstract

Sterilization temperatures to maximize volume average or surface quality retention were calculated for one‐dimensional conduction heating foods as a function of (1) Food Properties, (2) Processing Conditions and (3) Processing Criteria. A target lethality at the least‐lethality point was used as a constraint, and optimal temperatures were qualitatively and quantitatively compared for equal design variables. Average quality optimum conditions depend linearly on the inverse square of the Drefq‐value for the quality factor. These conditions do not vary linearly with all the other influential variables, opposite to what had been observed for surface quality. Optimum temperature for maximum average quality is always higher than the corresponding one for surface quality, but the difference is not constant. A systematic approach to the dependence of average quality optimal conditions on all the relevant parameters was carried out and quantitative relations were obtained. Optimum average quality retention is independent of surface heat transfer resistance.

Quality optimization of conduction heating foods sterilized in different packages

“…It would certainly be interesting to determine how much increased C. L. M . Silva Silva et al, 1992aSilva et al, , 1994.…”

“…Recently, generalized regression equations for predicting optimal Quality optimization lcase studies S 17 sterilization temperatures for conduction heating foods as a function of several influential variables (thermal diffusivity of the product, geometry and dimensions of the food or package, D and z value of the quality factor thermal degradation kinetics, surface heat transfer coefficient and target sterility value at the coldest point of the product) were reported in literature (Hendrickx et al. 1990Silva et al, 1992aSilva et al, , 1994 (Fig. 1).…”