Abstract
A total of 90 samples, (30 of each plain yoghurt, Kareish cheese, and Ras cheese) were randomly collected from street-vendors, groceries and supermarkets of different sanitary levels in Mansoura city, Dakahlia Governorate, Egypt. All samples were subjected to sensory, chemical and microbiological evaluation. The mean values of acidity% and fat% in plain yoghurt, Kareish cheese, and Ras cheese were 0.644±0.106, 1.54±0.066, 1.97±0.0578; 0.64±0.124, 5.88±0.7004 and 48.94±0.43 , respectively. Meanwhile, the mean values of protein%, lactose%, and SNF% in plain yoghurt were 2.2±0.094, 3.28±0.138 and 5.98±0.25, respectively. The mean values of salt% and moisture% in Kareish cheese and Ras cheese were 2.55±0.248, 2.38±0.079; 67.18±0.891 and 32.75±0.899, respectively. The mean values of Staphylococcus aureus, Coliforms and Enterococci in plain yoghurt, Kareish cheese and Ras cheese samples were 9.2x104±2.9x104, 4.12x105±1.3x105, 4.64x105±8.82x104; 10.5x104±2.16x104, 6.65x105±1.27x105, 2.39x105±6.54x104; 9.99x105±1.94x105, 3.73x105±6.11x104 and 3.38x105±9.17x104 cfu/g, respectively. The mean values of yeast and mold in Kareish cheese and Ras cheese were 1.27x105±1.24x104, 3.82x104±3.48x103; 1.16x105±4.24x104 and 7.06x104±3.27x104 cfu/g, respectively. Thus, strict hygienic measures should be followed during handling, processing and distribution of products to improve the hygienic quality of plain yoghurt, Kareish cheese and Ras cheese.

Key words: Plain yoghurt, Kareish cheese, Ras cheese, Coliforms, Enterococci, Staphylococcus aureus, yeasts and molds.