Microbiological changes throughout ripening of keş cheese

Abstract

Microbiological changes in Keş cheese, traditional Turkish raw cow’s milk cheese made without the addition of starter culture, were studied during 90 days of ripening. Physico-chemical parameters, pH, salt content and water activity (aw), as important parameters for microbial growth, were also determined. Lactic acid bacteria were predominant microbial group. The time of ripening significantly influenced the count of total aerobic mesophilic bacteria, psychrophilic bacteria, mould (P<0.05), Lactobacillus spp. and Lactococcus spp. (P<0.01) which increased during ripening. E. coli and coagulase-positive staphylococci were not detected. The counts of Enterococcus spp. (P<0.05), Staphylococcus-Micrococcus spp., Enterobactericeae and coliform bacteria decreased throughout ripening of Keş cheese, which was connected to the physico-chemical parameters. Water activity significantly decreased (P<0.05), while the salt content increased (P<0.01) during ripening of Keş cheese. The obtained results will contribute to the establishment of the microbiological quality standards for Keş cheese and give necessary information for formation of autochthonous starter culture, which will help to understand ripening process of sour dried cheeses and improve the traditional farmhouse cheese production.