الفهرس 
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Abstract
A total of 90 samples, (30 of each Plain yoghurt, Kareish cheese, and Ras cheese) were collected from street-vendors, groceries and supermarkets of different sanitary levels at Mansoura city, Dakahlia Governorate, Egypt. All samples were subjected to sensory examination then divided into two sub samples. The first sub sample was used for compositional quality evaluation while the second one was subjected to microbiological evaluation. The results can be summarized as follows: 7.1 Sensory evaluation of examined curd dairy products: The number of Plain yoghurt samples with no criticisms were 8 (26.66%), 7 (23.33%) and 10 (33.33) for flavor, body and texture andappearance criticisms, respectively.The number of Kareish cheese samples with no criticisms were 2 (6.66%), 4 (13.33%), 10 (33.33%) and 22 (73.33%) for flavor, body and texture, colour appearance and salt criticisms, respectively.The number of Ras cheese samples with no criticisms were 5 (16.66%), 9 (30%), 13 (43.33%) and 28 (93.33%) for flavor, body and texture, colour appearance and salt criticisms, respectively. 7.2 Compositional quality and sanitary evaluation: a. Plain yoghurt: The mean values for acidity, fat, protein, lactose, and SNF% were 0.62 ± 0.03, 0.87 ± 0.09, 2.20 ± 0.09, 3.28 ± 0.14 and 5.98±0.25, respectively. All of examined samples were with in accepted limit for acidity %, with Egyptian Standards (2005).b. Kareish cheese: The mean values for acidity, salt, moisture and fat/DM %were 1.54 ± 0.06, 2.55 ± 0.24, 67.18 ± 0.89 and 7.88 ± 0.70, respectively.All of the examined samples lied within the permissible limit for salt, moisture% while, 60% of examined samples was accepted for fat/ DM according to the Egyptian Standards (2005)c. Ras cheese: The mean values for acidity, salt, moisture and fat% were 1.97 ± 0.05, 2.38 ± 0.07, 32.75 ± 0.89 and48.94 ± 0.43 respectively.All of Ras cheese samples were complied with the legal requirements for moisture and fat/DM % stipulated by the Egyptian Standards (2005). 7.3 Microbiological evaluation of examined curd dairy products:a. Plain yoghurt: brThe mean values of Coliforms, Enterococci and Staphylococcus aureus counts for Plain yoghurt were 1.05x105 ± 2.16x104, 9.99x105 ± 1.94x105 and 9.2x104 ± 2.9x104, respectively.The incidence of Coliforms, Enterococci and Staphylococcus aureus in the examined samples were 18(60%), 18(60%) and 12(40%), respectively.The number of examined Plain yoghurt samples that complied with Egyptian Standards (2005) were 12(40%) and 18(60%) for Coliforms and Staphylococcus aureus, respectively.The frequency percentage of isolated Coliforms species from the examined Plain yoghurt samples were Citrobacter diversus 7(23.33%), Enterobacter aerogenes 5(16.67%), Enterobacter liqueficens 3(10%), Enterobacter Cloacae 4(13.33%), Escherichia coli 8(26.67%) and Klebsiella aerogenes 3(10%). b. Kareish cheese: The mean values of Coliforms, Enterococci, Staphylococcus aureus ,yeast and mold counts for the examined Kareish cheese were 6.65 x 105 ± 1.27 x 105, 3.73x105 ± 6.11 x104, 4.12 x 105 ± 1.30 x 105, 1.27 x 105 ± 1.24 x 104 and 3.82 x 104 ± 3.48 x 103, respectively.The incidence of Coliforms, Enterococci, Staphylococcus aureus, yeast and molds in the examined samples were 26(86.67%), 26(86.67%), 24(80%), 23(76.66%) and 23(76.66%), respectively. The number of examined Kareish cheese samples that complied Egyptian Standards (2005) were 4(13.33%), 6(20%), 7(23.34%) and 7(23.34%) for Coliforms, Staphylococcus aureus, Yeast and molds, respectively.The frequency percentage of isolated Coliform species from examined Kareish cheese were Citrobacter diversus, 8(15.4%), Enterobacter aerogenes 10(19.2%),Enterobacter liqueficens 6(11.5%), Enterobacter Cloacae 2(3.8%), Escherichia coli 9(17.3%), Klebsiella aerogenes 5(9.6%), Klebsiella edwardsii 8(15.4%) and Klebsiella pneumonia 4(7.8%).The yeasts isolated from the examined Kareish cheese samples were Candida albicans 15(50%), Candida famata 3(10%), Candida krusei 5(16.7%), Candida tropicalis 4(13.3%), Candida rugsa 1(3.3%) and Cryptococcus neoformans 2(6.7%). The molds isolated from the examined Kareish cheese samples was Aspergillus flavus 18(51.4%), Aspergillus niger 8(22.9%), Penicillium spp. 7(20%) and Mucor spp. 2(5.7%).c. Ras cheese:The mean values of Coliforms, Enterococci, Staphylococcus aureus and yeast and mold counts for Ras cheese were 2.39 x 105 ± 6.54 x 104, 3.38 x105 ± 9.17 x104, 4.64 x 105 ± 8.82 x 104, 1.16 x 105 ± 4.24 x 104 and 7.06 x 104 ± 3.27 x 103 cfu/g, respectively.The incidence of Coliforms, Enterococci, Staphylococcus aureus, yeast and molds in the examined samples were 25(83.33%), 23(76.66%), 24(80%), 22(73.33%) and 24(80%), respectively.The frequency percentage of isolated Coliform species from examined Ras cheese were Citrobacter diversus 6(17.6%), Enterobacter aerogenes 10(29.4%), Enterobacter Cloacae 1(2.9%), Escherichia coli 6(17.6%), Klebsiella aerogenes 9(26.6%) and Klebsiella pneumonia 2(5.9%). Yeasts isolated from Ras cheese samples were Candida albicans 9(32.14%), Candida famata 7(25%), Candida tropicalis 5(17.86%), Candida rugsa 4(14.28%) and Cryptococcus neoformans 3(10.72%). Molds isolated from Ras cheese samples was Aspergillus flavus 16(50%), Aspergillus niger 10(31.3%), Penicillium spp. 5(15.6%) and Mucor spp. 1(3.1%).Public health importance and its hazard on human was discussed for isolated microorganisms such as Coliforms, Enterococci, Staphylocccus aureus, yeast and mold. Therefore, the study recommended applying Strict hygienic measures to ensure production of high quality curd dairy products to be safe for human consumption.