The development of a scum in a commercial sports drink is of concern because the product
would be of poor quality, which may result in financial losses due to consumer rejection of
the product and hence a decrease in the firm’s market share. The scum could be harmful to
health and as such the firm could be litigated. Several factors, including microbial
proliferation, may be the cause of the development of a scum in sports drink, but the actual
cause seems not to have been established. The aim of this study was to characterise the scum
in sports drink and determine the effects of preservation factors (pasteurisation, chemical
preservatives and refrigeration) on its development.
Samples of the sports drink were taken at different stages of processing to determine the
effect of preservatives, pasteurisation and storage temperature on scum development. Some
samples were kept at room temperature (approx. 25°C) and others were kept in the
refrigerator (approx. 4ºC) during the study. A total of 150 samples were analysed over a
period of four months. The structural characteristics of the scum that developed in the sports
drink were determined by scanning electron microscopy (SEM) and elemental analysis. The
sports drink samples were analysed for their microbial load and microbial types. Consumer
acceptability of pasteurised and non-pasteurised drink was compared by conducting sensory
evaluation using a consumer panel of 60 panellists. Customer complaints recorded by the
sports drink manufacture that were due to scum development in the drink were also reviewed
to establish the impact of scum development on consumer acceptability of the drink.
The results of the study indicated that scum development was due to microbial contamination
of the drink. The causative organism of the scum was identified as Acinetobacter baumanii.
Acinetobacter baumanii is a gram negative non-spore forming coccobacilli and does not
ferment sucrose. Acinetobacter baumanii forms the scum in sports drink as a means of
protection from environmental stresses. The scum was found to be a compound of C, Si and
O. The non-pasteurised samples were slightly more acceptable to consumers compared to the pasteurised samples. The consumer acceptability of pasteurised drink samples was negatively
affected by the loss of aroma and flavour during pasteurisation. The preservation factors
(chemical preservatives, pasteurisation and refrigeration) had no effect on scum development.
To prevent post pasteurisation contamination, it is recommended that the pasteurisation
process be done at the filling stage instead of at the holding stage. The frequency of changing
rubbers and gaskets on the filling line should be at least every two months. The drink is
pasteurised at 90ºC for 20 seconds, this needs to be reduced to a level where it will not have
an influence on the loss of taste and aroma of the pasteurised drink, but without reducing the
effectiveness of pasteurisation. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/10582 |
| Date | January 2013 |
| Creators | Mapompo, Odwa Mcebisi. |
| Contributors | Siwela, Muthulisi., Kolanisi, Unathi., Yobo, Kwasi Sackey. |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
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