INCIDENCE OF COLIFORMS IN WHITE SOFT CHEESE WITH SPECIAL REFERENCE TO E. COLI

Coliforms generally are pointer to possible fecal contamination and reflect the hygienic standards of cheese processing. To determine the chemical and microbiological quality of some traditional Egyptian white soft cheese, a total of 200 samples represented by Tallaga, Feta, Baramili and Istamboli (50 samples each) were collected randomly from supermarkets, dairy shops and street-vendors in Giza Governorate, Egypt. Chemically; the averages of pH value and NaCl% in the examined cheese were 6.354, 3.732%; 5.018, 7.0%; 3.441, 6.702% and 4.465, 5.94% for Tallaga, Feta, Baramili and Istamboli cheese, respectively. Microbiologically; Coliforms, faecal Coliforms and Escherichia coli (E.coli) bacteria were detected in 86, 76 and 60% of Tallaga cheese, 64, 54 and 32% of Feta cheese, 88, 68 and 50% of Baramili cheese and 78, 64 and 54% of Istamboli cheese, respectively. The average Coliforms count was 1.3x10 ⁴ , 1.2x10³, 6.5x10³ and 3.6x10³ cfu/g, while, the fecal Coliforms average values were 2.1×10³, 3.1×10², 1.2×10³ and 6.3×10² cfu/g and E.coli average was 2.7x10², 1.8x10², 2.9x10² and 1.2x10² cfu/g for the examined samples, respectively. Serological identifications of the isolated E.coli revealed that 14, 6, 12 and 8% out of all examined cheese samples were pathogenic. The most relevant detected serotypes in cheese were related to enterohemorrhagic (EHEC) and enterotoxigenic (ETEC) strains. Also, enteroinvasive (EIEC) and enteropathogenic (EPEC) related serotypes have been detected in some examined cheese samples. The Coliforms content and incidence of different pathogenic E.coli serotypes reflect the poor hygienic conditions of manufacturing and absence of microbial load elimination. It could be concluded from the obtained results that there is a lack of a standardized method for production and keeping quality of white soft cheese. So, it's suggested to apply strict hygienic measures during all stages of white soft cheese production.