Estimation of the Quality of some Fermented Dairy Products in Cairo and Giza Governorates

A total of twenty samples of different types of Zabady and Raybe milk were collected from local markets in Cairo and Al-Giza governorates and stored in the refrigerator at 5±1°C. Microbiological, physicochemical, and rheological properties of collected samples were studied at the beginning, middle , and end of storage period. The results showed that the average values of acidity, pH, Viscosity, Syneresis, Water Holding Capacity (WHC%) and Radical Scavenging Activity (RSA%) of fresh samples ranged from 0.72±0.02 to 0.82±0.04%, 4.52±0.05 - 4.61±0.02, 3393±7.00 - 8535±9.00 cP, 2.70±0.04 - 3.88±0.07 (ml/5g), 20.70±0.18 - 45.92±0.19% and 14.69±0.13 - 21.62±0.12% , respectively. The collected fresh samples contained 11.25±0.15 - 14.86±0.19 % total solids. Microbiological analysis revealed that the collected fresh samples contained 7.95 to 8.52 (log cfu/g) lactic acid bacteria, 2.16 to 2.62 (log cfu/g) Coliform Bacteria and 2.25 to 2.33 (log cfu/g) Yeasts and Molds. The hardiness and gumminess of the high-fat traditional zabady samples were higher than the rest of the zabady samples, while the springiness, cohesiveness , and chewiness in the industrial zabady samples were higher than the traditional zabady. As the storage period progressed, chemical, physical, microbiological , and rheological changes occurred.