MICROBIOLOGICAL, BIOCHEMICAL AND RHEOLOGICAL CHANGES THROUGHOUT RIPENING OF KURDISH CHEESE

Kurdish cheese has been traditionally prepared from raw milk in the northeast of Iran. It is ripened in goat's skin bags. This study was conducted on microbiological diversity and physicochemical properties of Kurdish cheese during ripening (1, 20, 40 and 60 days). The results indicated that the type and counts of microorganisms were mainly influenced by ripening time. Lactic acid bacteria and Enterobacteriaceae were predominant during the first 20 days of ripening, and lactobacilli were the most common microorganisms found during ripening. The initial numbers of coliforms and E.coli decreased rapidly, whereas a gradual increase in counts of moulds and yeasts was noticed in the early days of ripening. Coliforms, Salmonella and coagulase-positive Staphylococcus spp. were undetectable in ripened cheese. The optimal time for consuming is after 60 days because the undesired biota decreased below dangerous limits. pH, moisture content and aw decreased during ripening. No significant variations were observed in protein values during ripening. The textural parameters such as hardness, chewiness and gumminess increased as ripening progressed, but springiness decreased. The level of microelements in cheese samples during maturation were in the following order Na>Ca>K>Zn>Cu. Practical ApplicationsKurdish cheeses have been traditionally prepared, and the market for them has existed in many parts of Iran for many years. Its microbial diversity originates from natural microbiota present in the raw milk, and environmental exposures are important points to consider for public health. There is an increased demand from consumers for high-quality natural food, free from contaminating microorganisms. Hence, indigenous lactic acid bacteria were identified successfully for production of fermented milk products with increased safety. Given the significant economic importance of Kurdish cheeses to a number of small domestic and industrial producers, particularly in the northeast of Iran, this study can be used to help implement strategies designed to enhance the product's microbiological and physicochemical quality.