![]() | يوجد فقط 14 صفحة متاحة للعرض العام |
المستخلص Microbiological quality, composition and some chemical properties were determined in 160 different cheese samples (40 from each of fresh Ras, Low salt (Tallagah), Domiati and Karish cheeses), randomly collected from various markets located in Cairo Metropolitan. The average composition and chemical properties of different cheese samples are not laid among the Egyptian standards (EOS 2000 and 2001). Microbiological examination reveal that the log (cfu/g) of total viable count were 7.320, 8.050, 8.010 and 8.140, yeast & moulds were 1.790, 2.828, 5.973 and 3.048, and E. coli were 2.680, 3.814, 5.347 and 4.382, in succession. Also, contamination with Salmonella spp. was recorded in 60, 57.5, 42.5 and 67.5 % out of the 40 samples of each cheese kind, respectively. The corresponding percentages for the presence of Staphylococcus aureus were 67.5, 62.5, 45 and70 %, successively. On the other hand, Aeromonas spp., E.coli O157:H7 and Listeria spp. could not be detected in all samples. The presence of pathogenic bacteria with high numbers of total viable, yeast and moulds an E. coli counts in these cheese samples would indicate poor hygienic quality during milk production and cheese manufacturing process. The inhibitory effect of growth medium pH and presence of sodium chloride and some commercial starters of LAB antagonistic to Staphylococcus aureus ss. aureus and Salmonella typhimurium were determined. The results show that strains varied in sensitivity to low pH and to high sodium chloride concentration but the Salmonella typhimurium could be more sensitive for low pH and high sodium chloride than Staphylococcus aureus ss aureus. Furthermore, acidity only was cause the inhibitory effect from LAB. |