Tegel Foods Limited produces an extensive range of poultry products which may contain various potential allergens. These include wheat, soy, milk, and egg, sometimes in combination. This research has two purposes. One was to examine three cleaning stages of processing equipments – Rinse only, Foam and rinse and Sanitise and rinse to validate the efficacy of cleaning required between production runs where the first but not the second product contains the allergen. The allergen chosen to model the cleaning efficacy was gliadin, a protein in wheat. The second aim was to quantify allergenic risk to consumers from inadequately cleaned conveyer surfaces. The commercial motives driving this research were as follows. Cleaning represents a loss in productivity and an increase in consumables costs, and if it can be minimised, this would be advantageous. The requirement to declare the possibility of cross-contamination on retail packaging can potentially adversely affect consumer response, and if these declarations can be avoided then this too would be a commercial advantage. Three approaches were adopted or developed, an ATP bioluminescence test, an ELISA test kit for gliadin, and a Coomassie Blue test to quantify protein given that most allergens are proteins. Fifteen trials were done in the High Care Zone and the Old Further Processing line of the Tegel Henderson Plant production area over a period of nine months. In a typical trial, gliadin values normalised to Uncleaned values fell from 1000 (Uncleaned) arbitrary units, to 60 (Rinse only), to 0.3 (Foam and rinse), to zero (Sanitise and rinse). Parallel ATP tests similarly showed a progressive decrease in values. Compared with Uncleaned, the relative gliadin value was less than the relative ATP value after Foam and rinse in 14 of 14 trials. After Sanitise and rinse the same result was obtained. In the equivalent trials with ATP and Coomassie Blue, after cleaning of Foam and rinse and Sanitise and rinse, the relative ATP values exceeded the relative Coomassie Blue values in four of the five trials. Therefore the considerably cheaper and simpler ATP test is not only an indicator of hygiene but also a good guide to gliadin concentration (gliadin test), and to allergen contamination in general on the basis that allergens are mostly proteins (Coomassie Blue). Modelling of second-product contamination has been done, and was based on knowledge of the absolute gliadin concentration on a typical Uncleaned conveyer surface, as established in the first part of this project. The concept of the worst-case scenario examined the highest possible risk that a sensitive consumer would be exposed to an allergenic dose of gliadin. A pickup efficiency fraction of 0.3 was assumed as an upper limit of contamination from conveyer to the surface of a previously uncontaminated chicken piece. The model showed that the highest concentration of gliadin on the second product would be 6.3 ppm which is below the legislated limit of low-gluten. Information of direct commercial interest to Tegel has been extracted from all these results, and suggestions for future research have been made.

Thesis (PhD(Civil Engineering)(Engineering, Built Env. and Inf. Tech.)) -- University of Pretoria, 2007. / Summary in English. Includes bibliographical references.

Thesis equivalent (M.P.H.)--University of Michigan, 1948.

Assignment (MPhil)--University of Stellenbosch, 2007. / Bibliography. Also availabe via the Internet.

Thesis (M.P.H.E.)--University of Michigan, 1944.

Thesis (M.S.P.H.)--University of Michigan, 1939.

Thesis equivalent (M.P.H.)--University of Michigan, 1948.

Thesis (M.P.H.E.)--University of Michigan, 1944.

Thesis (M.P.A.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 123-127). Also available in print.

Made available in DSpace on 2013-01-07T15:55:02Z (GMT). No. of bitstreams: 2 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) 17.pdf: 42052641 bytes, checksum: 6b3854ad65a07635a9365278fbd7c3eb (MD5) Previous issue date: 2007 / Analisa as diferentes imagens de sertão que acompanharam as iniciativas em torno da mudança da capital, e que interferiram na viabilização do projeto mudancista; o lugar do saneamento dos sertões nos projetos de governo na primeira metade do século XX; a permanência de uma preocupação com o clima e a salubridade do Brasil Central nas comissões organizadas nos anos 40 e 50; a participação ativa de Goiás na defesa da transferência da capital para a região do Planalto Central goiano e finalmente, uma análise sobre a importância do papel dos médicos e sanitaristas, ligados ou não ao governo, na construção de Brasília.