Antimicrobial activity of fermented Maillard reaction products, novel milk-derived material, made by whey protein and Lactobacillus rhamnosus and Lactobacillus gasseri on Clostridium perfringens

Objective The objective of this study was to evaluate the antimicrobial effects of fermented Maillard reaction products made by milk proteins (FMRPs) on Clostridium perfringens, and to elucidate antimicrobial modes of FMRPs on the bacteria, using physiological and morphological analyses. Methods Antimicrobial effects of FMRPs [whey protein plus galactose fermented by Lactobacillus rhamnosus 4B15 (Gal-4B15) or Lactobacillus gasseri 4M13 (Gal-4M13), and whey protein plus glucose fermented by L. rhamnosus 4B15 (Glc-4B15) or L. gasseri 4M13 (Glc-4M13)] on C. perfringens were tested by examining growth responses of the pathogen. Iron chelation activity analysis, propidium iodide uptake assay, and morphological analysis with field emission scanning electron microscope (FE-SEM) were conducted to elucidate the modes of antimicrobial activities of FMRPs. Results When C. perfringens were exposed to the FMRPs, C. perfringens cell counts were decreased (p<0.05) by the all tested FMRPs; iron chelation activities by FMRPs, except for Glc-4M13. Propidium iodide uptake assay indicated that bacterial cellular damage increased in all FMRPs-treated C. perfringens, and it was observed by FE-SEM. Conclusion These results indicated that the FMRPs can destroy C. perfringens by iron chelation and cell membrane damage. Thus, it may be used in dairy products, and controlling intestinal C. perfringens.