Shelf life of pasteurized milk is relatively short, mainly due to cold chain conditions. This study investigated the effects of different storage temperatures （8, 10 and 12 ℃） on acidity, microorganism index, physi...Shelf life of pasteurized milk is relatively short, mainly due to cold chain conditions. This study investigated the effects of different storage temperatures （8, 10 and 12 ℃） on acidity, microorganism index, physical and chemical indicators and sensory quality of pasteurized milk packaged in glass bottle to determine the main factor affecting the quality of pasteurized milk during shelf life under different tem- peratures. The results showed that within the first five days, the protein, fat, lactose and non-fat milk solids contents in the milk samples did not change under different storage temperatures; the acidity was almost unchanged at 8 and 10 ℃, and in- creased slightly at 12 ℃; the sensory quality of milk samples did not change at 8 and 10 ℃, and began to decline from the 4th d at 12 ℃; the aerobic plate count in the milk samples accorded with the requirement of national standard at 8 and 10℃, and exceeded the national standard on the 5th day at 12℃. No coliform bac- teria were detected in the milk samples within the storage time at 8 ℃. When the milk samples were stored at 10 ℃, the coliform group count exceeded the national standard on the 5th day. When the milk samples were stored at 12 ℃, coliform bacteria began to be found in the milk samples from the 2rd day, and the coliform group count exceeded the national standard from the 3rd day. It indicated that stor- age time had a great impact on the quality of glass bottled pasteurized milk. Low storage temperature and relatively short storage time were conducive to the reten- tion of high quality of pasteurized milk. Coliform group count was one of the impor- tant factors affecting the quality of glass bottled pasteurized milk during shelf life.展开更多
文摘Shelf life of pasteurized milk is relatively short, mainly due to cold chain conditions. This study investigated the effects of different storage temperatures （8, 10 and 12 ℃） on acidity, microorganism index, physical and chemical indicators and sensory quality of pasteurized milk packaged in glass bottle to determine the main factor affecting the quality of pasteurized milk during shelf life under different tem- peratures. The results showed that within the first five days, the protein, fat, lactose and non-fat milk solids contents in the milk samples did not change under different storage temperatures; the acidity was almost unchanged at 8 and 10 ℃, and in- creased slightly at 12 ℃; the sensory quality of milk samples did not change at 8 and 10 ℃, and began to decline from the 4th d at 12 ℃; the aerobic plate count in the milk samples accorded with the requirement of national standard at 8 and 10℃, and exceeded the national standard on the 5th day at 12℃. No coliform bac- teria were detected in the milk samples within the storage time at 8 ℃. When the milk samples were stored at 10 ℃, the coliform group count exceeded the national standard on the 5th day. When the milk samples were stored at 12 ℃, coliform bacteria began to be found in the milk samples from the 2rd day, and the coliform group count exceeded the national standard from the 3rd day. It indicated that stor- age time had a great impact on the quality of glass bottled pasteurized milk. Low storage temperature and relatively short storage time were conducive to the reten- tion of high quality of pasteurized milk. Coliform group count was one of the impor- tant factors affecting the quality of glass bottled pasteurized milk during shelf life.
