A SURVEY STUDY ON CHEMICAL, MICROBIOLOGICAL AND SENSORY PROPERTIES OF INDUSTRIAL RAYEB MILK PRODUCED IN EGYPT

A total of twenty-four industrial Raybe milk samples for six dairy products plants were collected from various supermarkets in Damietta and Al-Dakahlia governorates. Physicochemical, microbiological and sensorial properties of collected samples were studied at the beginning and the end of storage period (15 days). The results showed that the average values of acidity, pH and redox potential (ERhR) of fresh samples ranged from 0.63 to 0.80%, 4.92-5.20 and 130.8 to 168.7 respectively. The collected fresh samples contained 10.10 - 12.56% total solids, 1.4 - 3.5% fat and 2.01 - 3.74% total protein. Increase in acidity and ERh Rvalues and decrease in pH were noticed in Raybe milk samples during storage period. Microbiological analysis revealed that probiotic bacteria were detected in all fresh Raybe milk samples and also after 15 days of storage except one sample which didn’t contain B. bifidum at the end of storage stage. Counts of lactic acid bacteria and bifidobacteria gradually lowered during storage of collected samples. Coliform bacteria and moulds and yeasts were not detected over the storage period in various samples. Sensory evaluation scores were similar for different samples but samples of flavored Raybe milk gained the highest smell and taste scores.