Determination of Microbial Properties of Freeze Dried Traditional Cheese

Abstract

The use of dried cheese in food production and food preparation sectors is becoming increasingly widespread. Dried cheese is preferred because of their longer shelf life at room temperatures, smaller packaging sizes, practical use, and their ease of homogenization in food products. Various technologies are currently being used for the drying of cheese and efforts are still being made to develop new methods. Freeze drying is a highly preferred technique for the production of dried cheese due to high quality of the final product. Instant removal of water and low process temperatures ensure an effective prevention of chemical and microbial deterioration. In this study, White, Kashar and Tulum cheeses were dried by freeze-drying method. Physicochemical analyses were carried out on the first day in order to determine the initial quality of cheese samples. The moisture and salt content were highest in White cheese, titratable acidity and fat content were highest in Tulum Cheese. Freze dried cheese samples were stored in room conditions for 6 months and changes in microbial populations such as mesophilic aerobic bacteria, yeast and moulds, lactic acid bacteria, Staphylococci spp. and coliform group bacteria were determined. The results showed that Tulum Cheese contained highest microbial counts in general. The number of bacteria was 7.71±0.10 log cfu/g in Tulum Cheese, 5.70±0.07 log cfu/g in White cheese. Total counts of yeasts and molds were 7.37±0.06 log cfu/g for Tulum cheese and 4.92±0.07 log cfu/g for Kashar Cheese. Statistical analysis was performedby using Minitab Statistical Package Program to evaluate the results of microbiological analysis on dried cheese samples.