Evaluation of growth and metabolism of selected strain of probiotic lactobacillus acidophilus la5 in sterilized milk

The biological activity of probiotics is affected by various environmental factors each of which can influence the performance as well as the growth of probiotics for increasing the health of the consumers. The aim of is to investigate the effect of fructose , dose 0/5,1 ,1/5 and 2 present of the primary culture and temperature of 35 ,38 ,41 and 44 degrees centigrade on the growth and metabolism and metabolism of Lactobacillus acidophilus La5 in sterilized milk ; in order to do this ,the milk fermented with Lactobacillus acidophilus La5 (as the culture ferment ) was used for incubating the milk sample different; incubators were used as the suitable temperatures for the growth of microorganisms. The acidity and the pH of the milk samples were measured during different hours and the total number of microbial counts were and measured at 0 , 4 and 8 h after the incubation. In order to measure the effect of fructose 0/75 % (w/v) added the milk samples, and the resulted sample , together with the control sample , was kept in incubation at 41 degree centigrade ; and then the acidity , pH of Lactobacillus acidophilus La5 was measured and the total number of lactobacillus acidophilus was counted during the above mentioned periods after incubation . Every of above operations was replicate ten times ; then , utilizing statistical tests , were compared with one another during the above mentioned periods. The findings of the study indicated that the total number of bacteria and the amount of acidity in the incubated milk samples at 41 and 44 degrees centigrade were significantly greater than the other temperatures (P<0.05 ). The multiplication rate of the total hours of bacteria in samples containing 2 % of culture ferment during the fourth h of incubation was significantly greater than the other samples ( P<0.05 ); however , this difference in 8 h after the incubation was not significant. Concerning the use of prebiotic fructose, the total number of bacteria in and the acidity in the milk samples containing fructose was significantly greater than the number of control sample ( P<0.05 ). It is concluded from this study that The best alternative temperature for this purpose is an incubation temperature range of 41-44° C as well and if fructose is added to milk , there is a significant effect in enhancing the growth of Lactobacillus acidophilus La5.