[ effect of culture medium on metabolic and antibacterial activities of probiotic bacteria]

Probiotic bacteria is added directly to food components and it has beneficial effect on function and the health of organisms. The bifidogenic factors enter the colon where they contribute to an increase lactic acid bacteria population including Lactobacilli and Bifidobacteria and they inhibit enteric pathogenic bacterial growth. The aim of this study is to investigate the effect of culture medium on metabolic and antibacterial of probiotic bacteria. In this study, the probiotics bacterial and intestine pathogenic are to be used. Lactobacilli and Bifidobacterium were identified by plating samples on MRS medium, Gram Staining and standard biochemical methods. The effect of antagonistic probiotics was investigated in the presence of growth factor in the method well diffusion Ager on the Shigella flexneri [PTCC 1234], Escherichia coli [PTCC 1552], Salmonella typhi [PTCC 1609] and the culture medium pH was measured. The probiotics bacterial growth in MRS and lactose1%, sorbitol, raffinose, riboflavin were shown the effect antibacterial. The results of the study show the most antagonistic activity in commercial strain Lactobacillus acidophilus on Shigella flexneri and lower activity was in Lactobacillus casei [PTCC 1608], and Salmonella typhimurium [PTCC 1609], and also in Bbifidobacterium bifidum, it showed the most decrease pH value. According to the result of the study, adding growth factors to MRS medium base and lactose 1%, probiotic growth was increased and which also increased antagonistic activity

[Evaluating antimutagenic activity of probiotic bacteria isolated from probiotic products]

Probiotic bacteria are microbial nutrition supplements which have useful effects on human health by maintaining of bowel microbial balance. There are many studies that have been suggested the use of probiotic products as cancer risk reducer. The aim of this study, is isolation and detection of probiotic agents from yoghurt and probiotical tablet and evaluation of their abilities to decrease some effects of mutagenic and carcinogenic agents. In this study, probiotic bacteria were isolated from yogurt and probiotic tablet by using MRS in anaerobic condition [5% Co2 and gas peck] and temperature of 37[degree]c. Then, they were detected by using biochemical tests. Their anti mutagenic effects of supernatant culture were evaluated against mutagenic agents of azid Sodium and Potassium Permanganate by ames test [Salmonella typhimurium TA100] in presence and absence of S[9]. Six probiotic bacteria were isolated from yogurt and probiotic tablet. Their anti mutagenic activity results based on ames test showed they can inhibit mutagenic agents more than 40% in some species, which is considered as a good result. The results of this study show that the use of probiotic bacteria found in different products such as yogurt and probiotic tablets, have proper anti mutagenic and anti carcinogenic effects. They change the micro flora of bowel and, as a result, reduce absorption of mutagenic and carcinogenic agents and help to maintain human health