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Abstract

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.

Item Type:	Thesis - PhD
Authors/Creators:	Warne, D
Keywords:	Food adulteration and inspection, Food, Food contamination
Copyright Holders:	The Author
Copyright Information:	Copyright 2005 the author - The University is continuing to endeavour to trace the copyright owner(s) and in the meantime this item has been reproduced here in good faith. We would be pleased to hear from the copyright owner(s).
Additional Information:	For consultation only. No copying permitted until September 2007. Thesis (Ph.D.)--University of Tasmania, 2005. Includes bibliographical references
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