Inhibitory effects of bovine lactoferrin and lactoferricin B on Enterobacter sakazakii

The susceptibility of Enterobacter sakazakii, a food-borne pathogen, to several metal-bound forms of bovine lactoferrin (LF), pepsin-hydrolyzed LF (LF-hyd), and LF-derived peptide lactoferricin B (LFcin B) was tested. MIC and MBC testing revealed that 4 strains of E. sakazakii show susceptibility to apo- and Cu-LF, LF-hyd, and LFcin B, but not to Fe-LF, similarly to Escherichia coli. A growth curve test indicated that E. sakazakii was inhibited in a dose-dependent manner by apo-LF at 0.5 to 8 mg/ml. Even after being heated at 80 degrees C, LF at above 1 mg/ml inhibited the bacterial growth. These results suggest that bovine LF-related compounds may be useful for the inhibition of E. sakazakii in foods.