THERMAL-PROCESSING CANNED MEAT WITH SUB-FREEZING INITIAL TEMPERATURES- THERMAL AND MICROBIAL VALIDATION

Retorting from the frozen state is attractive with respect to product quality and economy and was investigated in canned bentonite and flake d ham. A two dimensional finite difference model was written in which thermal diffusivity varied with temperature. Heat penetrations were co mpleted with initial temperatures of 0, -5 degrees, -10 degrees, -15 d egrees and -20 degrees C. In ham, decreasing initial temperatures resu lted in increased lag factors (j(h)) but did not affect heating rate i ndex (f(h)). In bentonite, f(h) but not j(h) increased. D and Z of Clo stridium sporogenes PA 3679 spores were not affected by previous freez ing. Sub-freezing initial temperatures were judged to be consistent wi th safe processes if validated with heat penetration studies.