Studies on the biological properties of Lactobacillus acidophilus and its fermented milk

The biological properties of Lactobacillus acidophilus were studied and the processing technology of fermented milk was chosen. The result indicated: the rate of acidity and the living cells number of Lactobacillus acidophilus were improved obviously in the medium of 11 % NFM + 7% beer. The ability of salt-tolerance, bile-tolerance and rate of assimilating cholesterol were 6. 0% , 1. 5% , about 80% respectively, which proved the strain was good. The processing technology of fermented milk were: ① using lactose hydrolyzed milk (hydrolysis rate 40% ) and inoculating 3% Lactobacillus acidophilus; ② using general yogurt technology and inoculating mixed starter ( Lactobacillus acidophilus + Streptococcus salivariu ssp. thermophilus + Lac. Delbrueckii subsp. bulgaricus = 3% +0. 5% +0. 5% ). The living cells number was 109 mL -1 and 6 × 108 mL-1 after 5 days, and the flavor was good.