Iranian Journal of Medical Microbiology (Jun 2017)
Investigating of the antimicrobial effects of isolated Weissella cibaria and its cell free culture filtrate obtained from different growth phases
Abstract
Background and Aim: Lactic acid bacteria play an important role in production and storage of fermented foods. This study aimed to evaluate the antimicrobial properties of a dominant lactic acid bacteria isolated from barley sourdough against some of foodborne indicator bacteria. Materials and Methods: In this experimental study which was conducted in 2015-2016 at Gorgan University of Agricultural Sciences and Natural Resources, after molecular identification of dominant lactic acid bacteria isolated from whole barley sourdough, antimicrobial effect of the isolate and it’s cell free culture filtrate as native and neutralized cell free culture filtrate obtained from logarithmic and stationary phases were investigated based on disc diffusion and microdilution (antibacterial effect) and overlay and agar spore spot (antifungal effect) methods. Results were also compared by the one way analysis of variance. Results: Sequencing results of PCR products lead to identification of Weissella cibaria as a dominant lactic acid bacteria isolated from whole barley sourdough. Based on the results of investigating of the antibacterial effect the highest antagonistic effect of the isolate and it’s native cell free culture filtrate obtained from logarithmic phase were observed against Bacillus subtilis that was significantly (P<0.05) more than the other indicator bacteria. Furthermore, W. cibaria and it’s cell free culture filtrate had proper antifungal effects on Aspergillus flavus and Aspergillus niger. Conclusions: Based on the results of this study, it is possible to use W. cibaria and it’s cell free culture filtrate as biopreservative for controlling some microbial indicators in food and medical industries.
