Evaluation of antimicrobial properties of bovine lactoferrin against foodborne pathogenic microorganisms in planktonic and biofilm forms (in vitro)

Lactoferrin is one of the most important components in milk. Lactoferrin is an 80 kDa iron-binding glycoprotein that involves a diverse range of biological activities. However, the antimicrobial properties are its most widely studied function. The aim of this study was to assay the antimicrobial and antibiofilm activities of bovine lactoferrin against five of the most important foodborne pathogenic bacterial strains including Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Listeria monocytogenes and Listeria innocua, in planktonic and biofilm forms. Bovine lactoferrin was purchased, MIC and MBC were determined for the mentioned bacterial strains and the effect of lactoferrin concentrations on biofilm formation was evaluated using microtiter plate method. Based on the results, lactoferrin had a greater effect on gram-positive bacteria, L. monocytogenes and L. innocua were the most sensitive strains. MIC for L. monocytogenes, L. innocua, S. aureus and P. aeruginosa was 6, 6, 8 and 14 mg/mL, respectively, Nevertheless, MIC for gram negative E. coli was not observed, even at 16 mg/mL. The result demonstrated that MBC for L. monocytogenes, L. innocua and S. aureus were 10, 12 and 16 mg/mL, respectively. However, MBC for P. aeruginosa and E. coli were not observed for the lactoferrin concentrations evaluated. The highest biofilm formation inhibitory effects of bovine lactoferrin were against L. monocytogenes and L. innocua. To our knowledge, this is the first report on the antibiofilm activity of bovine lactoferrin against foodborne pathogenic bacteria. Our findings suggest lactoferrin to possibly use as an anti-biofilm agent in both food and pharmaceutical industries.