국내 시판 우유의 보존성 비교

This study was carried out to investigate the keeping quality of market milks collected from several dairy processing companies. Microbiological, chemical, and sensory properties of Ultra-high temperature(UHT) treated milks stored at 5, 10, 15℃ were evaluated during the storage of 15days. No significant difference during the storage was shown in bacterial counts, pH and titratable acidity. Standard plate count(SPC) was remained less than 20,000 cfu/ml after 15 day storage at 5, 10, 15℃. Also, Psychrotrophic bacterial count and Coliform count were not detected or detected at low level. The pH ranged from 6.55 to 6.83 and the titratable acidity ranged from 0.13% to 0.16%. In sensory evaluation, UHT milks showed normal flavor until 10days, but thereafter off-flavor was slightly developed. Consequently, UHT milks remained in good quality when stored at 5℃,10℃ until 15days except sensory properties, According to this experiment, the shelf-life of UHT milk can be extended to 10 days, even though maintaining the storage temperature strictly below 10℃ in milk market is not easy.