Safety Assessment of Bacillus licheniformis Me1 Isolated from Milk for Probiotic Application

Abstract

In this study, an in vivo toxicological safety assessment of Bacillus licheniformis Me1, a native isolate from milk, was performed. An acute toxicity study in male albino Wistar rats demonstrated no treatment-related illness or mortality. A 90-day subchronic oral toxicity study using 2 doses (1.1 × 1010 and 1.1 × 1011 colony-forming unit [CFU]/kg body weight [BW], respectively) failed to show dose-dependent illness or mortality. Moreover, neither significant differences in serum biochemical and hematological analyses nor histopathological changes in organs or tissues were found when compared to the control groups. The no-observed-adverse-effect level (NOAEL) was found to be greater than 1.1 × 1011 CFU/kg BW. The in vivo micronucleus assay in mice did not reveal any signs of genotoxic effect at any of the doses tested. Furthermore, dermal and acute eye irritation tests conducted in rabbits showed no edema or erythema and ocular lesions. These results suggest that B licheniformis Me1 can be considered safe for food industry applications.