Assessing safety of Lactobacillus plantarum MTCC 5690 and Lactobacillus fermentum MTCC 5689 using in vitro approaches and an in vivo murine model.

Lactobacilli have a long history of safe use in human nutrition, however, inclusion of any new strain, despite its safe usage evidence, warrants proper analysis of its safety and toxicity under the purview of existing regulations. In the present investigation, Lactobacillus plantarum MTCC 5690 and Lactobacillus fermentum MTCC 5689 were evaluated for their safety and toxicity using both in vitro and in vivo approaches. The in vitro assays included mucin degradation, hemolytic activity, biogenic amine production and platelet aggregation assay. The safety was also assessed using acute, subacute and subchronic assays, bacterial translocation studies, intravenous and intravenous administration and genotoxicity assay in murine model. The outcome of this toxicological safety assessment indicated that both the test strains lacked any harmful metabolic activity or any genotoxic effects. Furthermore, the results of oral toxicity studies in mice revealed that short term administration of high cell mass concentration of 1012  cfu/animal as well as long term feeding of the probiotic strains did not alter any hematological, general health parameters or cause any organ specific disorder. Based upon these scientific assessments and supported by long history of safe use, both MTCC 5690 and MTCC 5689 may be considered safe for human consumption.