Abstract

We conducted this study to evaluate the differences in microflora and physicochemical properties of some traditionally manufactured soft white cheeses upon purchase from Zagazig city, Egypt, in 2010 and 2011. A total of 168 samples were analyzed for both spoilage (total viable count, lactic acid bacteria, yeasts and moulds, staphylococci, Enterobacteriaceae, and coliform group) and pathogenic (Salmonella spp., Escherichia coli, Staphylococcus aureus, and fecal Streptococci) microorganisms. Physicochemical analyses showed low levels of pH and high levels of salt. Two cheese samples were unsatisfactory due to levels of Staphylococcus aureus at 4.00 log cfu/g, and fecal streptococci at 4.3 log cfu/g. Despite the much lower spoilage microorganisms counts in the pasteurized cheeses, soft Feta of dairy M showed the highest contamination level of 4.11 and 3.72 log cfu/g of total viable count and staphylococci, respectively. Fifty-two isolates of the yeasts were identified using the physiological and biochemical tests, and were classified into seven species. Ten of the species were selected for identification by sequencing the 26S rRNA, where nine of them were identical to the phenotypic identification. These results emphasize the need for applying more strict hygienic practices especially in thermized cheese processing to minimize microbial contamination.

Key words: Egyptian soft white cheese, spoilage microorganisms, pathogenic bacteria, yeast identification.