Impact of cold storage and blending different lactations of cow's milk on the quality of Domiati cheese

Abstract

The present investigation studied the making of Domiati cheese from raw or pasteurized cow’s milk stored at 4 - 5°C for 24 or 48 h as well as the effect of mixing equal amounts of evening and morning milk with cold stored cow's milk on some properties of Domiati cheese. Domiati cheese made from cooled stored cow's milk, either raw or pasteurized, had lower yields, TS, fat, TN and higher acidity, salt, salt in moisture, WSN, WSN/TN, NPN, NPN/TN and TVFA contents relative to the control. Adding of evening and morning milks to raw or pasteurized refrigerated stored milk decreased the yield, acidity, WSN, WSN/TN, NPN, NPN/TN and TVFA and raised TS, fat, salt, salt in moisture, TN and TN/DM values of cheese. Mixing of raw or pasteurized evening and morning milk with cold stored milk had no clear effect on free amino acids (FAA) contents of cheese. Cooling of cow's milk for 24 or 48 h decreased concentrations of the majority of FAA of Domiati cheese stored for 90 days. Adding evening and morning milks to cold stored milk or preservation of both raw and pasteurized cow's milk for 24 or 48 h at 4 - 5°C raised the numbers of various microbial groups. Key words: Milk preservation - morning and evening milks- soft cheese.