Abstract: Probiotics are useful bacteria, which after consumption, inhibit the harmful microorganisms in the intestines and leave useful effects on human health. 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. This study aims to study the effect of fructose, prolin doses of 0.5, 1, 1.5 and 2% of the primary culture and temperatures of 35, 38, 41 and 44°C on the growth as well as 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) and incubated at 35, 38, 41 and 44°C. The acidity and the pH of the milk samples were measured at 0, 2, 4 and 8 h and the total number of microorganisms were counted at 0, 4 and 8 h after the incubation. In order to measure the effect of fructose and prolin, 0.75% (w v-1) of fructose and 1% (w v-1) prolin was added to the milk samples and samples together with the control sample, was kept in incubator at 41°C and then acidity and pH of was measured and the total number of lactobacillus acidophilus was counted at 0, 2, 4 and 8 h after incubation. All the above trials were replicated ten times. The findings of the study using statistical tests indicated that the total number of bacteria and the amount of acidity in incubated milk samples at 41 and 44°C 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 during the fourth hour 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 probiotic, fructose and prolin, the total number of bacteria and acidity in the milk samples containing fructose was significantly higher those of prolin and sample containing control sample (p<0.05).
G. Karim, H. Karimi Darhabi and H. Mirzaei, 2009. The Effect of Fructose, Prolin, Initial Doses and Different Temperatures on the Growth and Metabolism of Lactobacillus acidophilus La5. Journal of Animal and Veterinary Advances, 8: 2432-2437.