microbiological diversity in kurdish cheese throughout ripening and its relationship with physicochemical and sensory characteristics

kurdish cheese is semi-firm cheese which has been traditionally manufactured from whole raw cow or sheep milk, in the east of iran. it is ripened in goat’s skin bags. the microbial diversity of kordish cheese originates from natural microbiota present in the raw milk and its unique organoleptic properties have made it excellent among other traditional cheeses in iran. this study has been conducted to evaluate microbiological diversity during ripening of kurdish cheese. samples were taken from 6 batches of cheese on day 1, 20, 40 and 60. sensory properties of kurdish cheeses were determined at 60,120 and 180 days of ripening. based on results, the diversity and microorganisms count of were mainly influenced by ripening time. lactic acid bacteria and enterobacteriaceae were the predominant families of micro-organisms during the first 20 days of ripening and lactobacilli was the most abundant lactic acid bacteria in cheese. coliforms and e.coli decreased more rapidly in cheese, whereas mows and yeasts decreased gradually and then increased in ending days. at the end of ripening period, mo coliforms, salmonella and coagulase positive staphylococcus were detected in the samples. changes in textural and chemical characteristics in relation to ripening time showed that; ph, moisture, total solid, aw and fat content of samples decreased during 40d and reached to 4.69, 33.9, 64.07, 0.927, 28.1 at 60 days respectively. no significant variations observed in protein values during ripening period. the values for sensory characteristics such as taste, aroma, colour and total acceptance of the full-ripened cheeses (120th days) increased as ripening progressed. according to our results, from a safety point of view, the optimum time for consuming kurish cheese would be after passing ripening time of 60 days (during 1-2 months) due to decrease in ph, undesirable flora and increase in desirable lab counts.