Evaluation of some chemical and microbiological aspects of commercial yoghurt in Sharkia province

Document Type : Original Articles

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Abstract

Two hundred random samples of yoghurt, collected from dairy shops and supermarkets in Sharkia province, Egypt, were analysed chemically and microbiologically. The chemical examination revealed that the mean percentage values ( range ) for total solids fat and solid – not – fat were 19.50 ( 16.6 – 23.6 ), 2.07 ( 1.5 – 2.7 ) and 17.43 ( 14.4 – 20.3 ) respectively. While, the mean pH value ( range ) was 3.9 ( 3.5 – 4.5 ). The microbiological examination revealed that the mean total colony count, coliform and yeast and mold counts were 1.1 * 10^7, 2.3 and 6.5 * 10^2 CFU/g respectively. Escherichia coli, Enterobacter agglomerans, Klebsiella oxytoco, Klebsiella pneumonia, citrobacter freundii,penicillium spp., Aspergillus spp., Mucor spp., Rhizopus spp., Saccharomyces spp. And Kluyveromyces spp. Could be isolated from the examined yoghurt samples at varying percentages ranging form 1.0% to 12.5%. The yoghurt samples were graded as medium fat according to fat content. While, 6 (3.0%) and 60 (30.0%) out of 200 examined yoghurt samples were graded unsatisfactory according to coliform and yeast and mold counts respectively. Control measures for improving the hygienic quality of yoghurt and to safeguard the consumers were suggested.

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