Effect of rennet type, container and ripening period on physicochemical and microbial properties of local Kurdish cheese

Traditional Kurdish cheese is one of the most consuming raw milk cheeses in Iran which there is a few studies accomplished about it. In this study، the effect of ripening period، type of containers (goat skin and plastic containers) and rennet type (traditional rennet and commercial rennet) were evaluated on the physicochemical and microbial characteristics of Kurdish cheese. Physicochemical analysis were involved the measuring of ash، dry matter، pH، fat to dry matter and protein to dry matter ratios and microbial analysis were including total count of mesophilic and termophilic lactobacilli، mesophilic and termophilic lactococci، aerobic psychrotrophic and mesophilic bacteria، entrobacters، entrococci and the total molds and yeasts. The results showed that، both rennet type and containers had no significant effect on microbial load of the cheeses (p>0. 05) whereas the numbers of mesophilic lactobacilli، termophilic lactococci، aerobic psychrotrophic bacteria، entrobacters along with total molds and yeasts have changed during the time (p<0. 05). The amount of dry matter، ash and pH of the cheeses were significantly affected by the containers (p<0. 05) and rennet type also had a significant effect on dry matter، ash and ratio of fat to dry matter (p<0. 05). All the characteristics of cheese were affected by the time of ripening (p<0. 05) except the ratio of protein to dry matter. Finally، according to all results، it seems that cheeses produced by traditional rennet have more nutritional quality than the others manufactured by commercial rennet. Also، using of traditional rennet and goat skin (which traditionally use in the production of Kurdish cheese) had no significant effects on microbial quality of cheeses (p> 0. 05).