Effect of some probiotics on Salmonella paratyphi during associated growth in milk

Abstract

The aim of this study is to determine the effects of Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium angulatom and Bifidobacterium bifidum on salmonella paratyphi in associated condition in milk. At first a quantity of 1.5 × 108 cfu/ml activated S. paratyphi was added to 500 ml of sterile milk and after homogenization distributed equally in five erlene meyers. The first erlene meyer was considered as individual culture and in to the second, third, fourth and fifth erlene meyer a quantity of 1.5×108 cfu/ml of the above probiotic was inoculated respectively and after 24-48 hours of incubation at 37 oC, pH was measured by pH meter and S. paratyphi count was determined by pour plate method in SSA medium. This procedure was repeated 10 times and the mean of pH and number of S. paratyphi in one ml of individual culture and with probiotic cultures was compared using statistical analysis. According to statistical tests of ANOVA and Tukey at α=0.05, in 24 and 48 hour incubation of associated growth of L. acidophilus, L. casei and B. bifidum had significant inhibitory effect on S. paratyphi growth (p

Keywords

• Salmonella paratyphi
• probiotics
• associated growth
• Milk