Microbiological Evaluation of Some Fermented Milk Products Retailed for Sale at Local Markets

Abstract

The consumption of fermented milks by man dates from the beginning of civilization. Fermented milk products are dairy foods that have been fermented with lactic acid bacteria such as Lactobacillus, Lactococcus and Leuconostoc. One hundred random samples of some locally manufactured fermented dairy products including; plain yoghurt, stirred yoghurt, flavored yoghurt, homemade rayeb, and sterilized rayeb (20 of each) were collected from local markets to be examined for their microbiological fitness. The obtained results clarified that the mean value of Coliforms count was 4.10×102 ± 2.0×10, 1.72×102 ± 2.1×10 and 1.65×103 ± 2.69×102 6.10×102 ± 6.4×10 for plain yoghurt, flavored yoghurt and homemade rayeb, respectively. The mean value of S. aureus count was 2.0×10 ± 1.0×10, 6.4×10 ± 4.5×10, 7.23×102 ± 5.4×10 and 1.32×102 ± 2.1×10 stirred yoghurt, flavored yoghurt, homemade rayeb and sterilized rayeb, respectively. Moreover, yeast and molds counts were performed. It could be concluded that the majority of investigated fermented dairy products were contaminated, at different degrees, with Coliforms, S. aureus, yeasts and molds giving an indication of poor sanitary measures adopted during manufacturing, storage, handling, and distribution of these products. In addition, it was observed that homemade rayeb had lower quality than other fermented dairy products.