A NEW, MODIFIED ACID-PHOSPHATASE ASSAY FOR DETERMINING THE EXTENT OF HEAT-TREATMENT IN CANNED HAMS

A modified acid phosphatase assay is presented in this paper for indication of heat treatment in canned hams. Adequate blending of the sample, increased substrate concentration and working at the pH optimum in the reaction mixture considerably improved the sensitivity of the method. Difficulties arose with the use of concentrated meat slurries: high rate of adsorption of released phenol from phenyl phosphate and reduced activities for the high level of endogenous competitive inhibitors (phosphates). Taking the thermal processing curve of Lind as reference, a heat treatment equivalent F(c) {70-degrees-C} = 80 min value is provisionally proposed (at Z = 6.94-degrees-C) for the central area of the cans instead of the not unambiguous end-point temperature regulation (69-degrees-C/156-degrees-F). This F(c) value assures the destruction of heat resistant Streptococci in the product. However, at present, such F(c) and Z values are not available for the FMD virus. An adequate inspection system, based on mathematical statistical considerations is also briefly discussed here. In conclusion, results of this study indicate that the new, modified method has potential for the successful and rather simple measurement of the extent of heating in canned hams.