Anti-biofilm effect of crude bacteriocin derived from Lactobacillus brevis DF01 on Escherichia coli and Salmonella Typhimurium

Biofilm is a community of microorganisms that adhere to abiotic or biotic surfaces, and is problematic in a wide range of food industries, as well as to human health. Although bacteriocin from lactic acid bacteria is well known as a natural antimicrobial agent in food preservation, it has been poorly investigated that bacteriocin inhibits the biofilm formation of foodborne pathogens. In this study, we demonstrated that bacteriocin produced by Lactobacillus brevis DF01 was partially purified and investigated whether the bacteriocin inhibited the biofilm formation of Escherichia coli and Salmonella Typhimurium. Assessment by the microtiter plate method, as well as by fluorescence and scanning electron microscopy, showed that the biofilm formation of E. coli and S. Typhimurium was reduced when the bacteria was co-incubated with crude bacteriocin of L. brevis DF01 (DF01 bacteriocin). Although pre-treated DF01 bacteriocin also significantly inhibited the biofilm formation of E. coli and S. Typhimurium (P = 0.0035 and P = 0.0003, respectively) post-treatment with DF01 bacteriocin did not significantly inhibit the biofilm formation (P = 0.1314 for E. coli and P = 0.2939 for S. Typhimurium), suggesting that DF01 bacteriocin interfered with biofilm formation, but did not disrupt the established biofilm of E. coli and S. Typhimurium. In addition, biofilms of both E. coli and S. Typhimuriun on the surface of stainless steel coupons were decreased in the presence of DF01 bacteriocin. Taken together, these results suggest that DF01 bacteriocin may be applied to control the biofilm formation of E. coli and S. Typhimurium.