The influence on food safety of technological developments in the commercial manufacture of shelf-stable and refrigerator-stable heat-processed foods

Several techniques were adopted to evaluate the influence on food safety of technological developments in the commercial manufacture of shelf-stable and refrigerator- stable heat-processed foods and these were as follows: 1. Development and assessment of a predictive model (known as DWC's Method) for calculating process lethality across a range of processing conditions. After analysis of data from 15 different heat penetration trials conducted in commercial manufacturing plants it was found that DWC's Method computed F values with errors of between -6 and +4% of the theoretical values calculated with an internationally accredited reference model (FMC's NumeriCal), whereas the model that is used extensively by manufacturers and regulators in Australia and New Zealand produced average errors of between -27 and -40% of the theoretical values calculated with NumeriCal. 2. Determination of the adequacy of thermal processes in commercially manufactured refrigerator-stable heat-processed foods (known as refrigerated pasteurised foods of extended durability or REPFEDs) and comparison of Fp values received in these processes with those recommended in Good Manufacturing Practice (GMP) guidelines. Of 16 thermal processes that were considered 11 (69%) satisfied GMP while, in five instances (31 %), the thermal processes failed to deliver minimum Fp requirements and, in three of these cases, safety would have been compromised. 3. Evaluation of the adequacy of thermal processes used in commercially manufactured shelf-stable foods and comparison of F0 values received in these processes with those recommended in GMP guidelines. Of 32 thermal processes reviewed, 25 (78%) had F0 values~ 2.4 min which satisfied GMP, while in seven instances (22%) the F0 values were< 2.4 min and were insufficient for safety. 4. Development and evaluation of microbiological challenge techniques (known as Biotests) to assess the ability of hermetic seals to prevent post-process leaker contamination (PPLC) in metal cans, glass containers and barrier plastic trays and pouches used in commercial manufacture of shelf-stable foods. 5. Development of a software package (known as DWC Analyser) to evaluate data gathered during heat distribution studies in retorting systems. 6. Evaluation of the performance of 16 commercial retorting systems in terms of compliance with GMP guidelines issued by international processing and regulatory authorities. It was found that three systems (19%) complied with the United States Food and Drug Administration requirements (Anon., 2002), which were the strictest of all the guidelines considered; five (31%) complied with guidelines recommended by May (1997a), Smout and May (1997) and the writer, and eight (50%) of the retorts failed to comply with any recognised GMP guidelines.