Safety and quality assessment of some Egyptian traditional dairy products: trials for improving Karish cheese

Abstract

Two hundred (200) random samples of some traditionally produced dairy products (Ras, Domiati, Karish cheeses and Mish) (50 each) were examined to determine their chemical and microbiological quality. 1. Chemical analysis: The mean values of moisture, salt and acidity % for Ras cheese were (30.3, 3.30 and 0.65), respectively, while (56.44, 6.63 and 0.68) for Domiati cheese, (77, 0.95 and 0.63) for Karish cheese and (85.70, 7.56, 0.50) for Mish samples, respectively.

2. Microbiological examination: Mean counts of total bacteria, presumptive coliform, staphylococci, yeast and mold were (2×108, 3×105, 1×106, 3×105 and 7×103) for Ras cheese, (3×106 5×10, 4×105, 1×105 and 4×103) for Domiati cheese, (9×106, 5×10, 3×103, 8×105 and 7×102) for Karish cheese and (1×107, 5×102, 1×105, 5×105 and 3×104) for Mish samples, respectively. The examined samples were positive for E. coli in 8, 4, 30 and 4 % of Ras, Domiati, Karish cheeses and Mish. The serological identification of suspected isolated E. coli using slide agglutination test revealed that E. coli O125 was isolated from Ras and Domiati cheese samples, E. coli O18 was isolated from Ras samples, while E. coli O114 was detected in Mish samples. Some E. coli strains isolated from the present study were positive for (phoA) gene by molecular