Antimicrobial activity of ovine whey protein and their peptic hydrolysates

The antimicrobial activity of ovine whey proteins and of their peptic hydrolysates were measured against different pathogenic microbial strains. Contrary to intact α-lactalbumin and β-lactoglobulin, their peptic hydrolysates inhibited the growth of Escherichia coli HB101, E. coli Cip812, Bacillus subtilis Cip5265 and Staphylococcus aureus 9973. This inhibitory action was dose-dependent against all the studied bacterial strains. RP-HPLC separation of peptic peptides of β-lactoglobulin demonstrated that the simultaneous presence of hydrophilic and hydrophobic peptides was necessary to antimicrobial activity. No antimicrobial activity was detected against Salmonella enterica Cip5858, Listeria innocua R1007 or Streptococcus mutans Cip103220T.