Abstract:
This study was conducted to evaluate the quality of
yoghurt supplied to consumers from retail outlets in Khartoum State. Yoghurt
samples (144 samples), which represent three different manufacturers (A,
B and C) beside traditional producers (T) were collected. The samples
included 96 plain yoghurt samples and 48 fruit yoghurt samples. All yoghurt
samples were analyzed for chemical parameters (total solids, SNF, fat,
protein, ash %, titratable acidity and pH) and the microbiological tests
(total bacterial count, coliform count and the yeast and molds count).
The means for total solids %, solids non-fat (SNF), fat, protein, ash
% and pH for the plain yoghurt samples were 14.04 ± 1.83, 10.86
± 1.53, 3.18 ± 1.01, 3.44 ± 0.58, 0.678 ±
0.146 and 4.62 ± 0.10, respectively. Whereas for the fruit yoghurt
samples the means were 21.70 ± 1.34, 19.70 ± 1.27, 2.00
± 0.62, 3.90 ± 0.50, 0.661 ± 0.087 and 4.68 ±
0.12, respectively. The means of microbiological measurements for the
plain yoghurt samples were log 9.10 ± 9.86, log 4.03 ± 4.41
and log 4.09 ± 4.57 for the total bacterial count, coliform count
and yeast and molds count, respectively. Whereas in the fruit yoghurt
samples the means were log 8.63 ± 9.99, log 3.59 ± 4.15
and log 3.15 ± 3.64, respectively. Results obtained revealed significant
variations (p ≤ 0.001) between samples obtained from different manufacturers
in their chemical composition. One hundred and thirty eight of collected
samples (96.5%) were found satisfying the international standard for solids
non-fat content, however, 73 yoghurt samples (50.7%) were found to have
a lower fat content than the standard. In the microbiological parameters
tested, the total bacterial count and yeast and molds count were not significantly
different between different manufacturers. The coliform count of samples
varied significantly (p ≤ 0.001) between manufacturers and with a significance
higher (p ≤ 0.05) coliform count in samples collected from traditional
manufacturers than that collected from modern manufacturers.
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