Effect of Culture Time on Cell Concentration in Home-made Fermented Milk Inoculated with Commercial AB Lactic Acid Bacteria

• Main Authors: Jou-hsin Wu, 吳柔幸
• Other Authors: Yaw-nan Chang
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/83912058952289341696

碩士 === 大葉大學 === 生物產業科技學系碩士在職專班 === 93 === In this study, the cell growth concentration of the fermented milk inoculated with the strain of AB lactic acid bacteria from various (A, B, C) brands of commercial drinking yoghurts in a home-made (DIY) fermentor was investigated. It was found that AB lactic acid bacteria in the fermented milk with initial 8% NFNS (non-fat milk solid) was recovered at a level of over 7 log CFU/mL, where the cell counts was7.42, 8.28and 8.53 log CFU/mL for A, B and C brand, respectively, after 8 h of cultivation in a home-made fermentor. The pH of the fermented milk declined and the titratable acidity rose during the cultivation period. After 12 h of cultivation the fermented milks were then held at 4℃ cold room for a period of 14 days. Population of the AB lactic acid bacteria reduced at the 4th, 8th, 2nd day of storage time for A, B and C brand, respectively, while the pH of the fermented milks little decreased during the storage period and the titratable acidity reached a maximum after 10 day. The growth test of coliform and E. coli for the fermented milk in the home-made fermentor was not detectable. It will be good and safe for consumers to drink the fermented milk made in the DIY drinking-yoghurt fermentor at home.