Antimicrobial activity of fatty Nacylamino acids against Grampositive foodborne pathogens

Abstract

The inhibitory effect of fatty N-acylamino acids on Gram-positive food-borne pathogens was examined. Myristoyl (C14) derivatives gave the greatest activity, followed by lauroyl (C14) and palmitoyl (C14). Derivatives of aromatic amino acids were most active, particularly phenylalanine. D-Isomers were inactive, as were the esters of active derivatives. Minimum inhibitory concentrations of as low as 8.5 ·g ml-1 were obtained with myristoyl-phenylalanine (Myr-Phe), the most active derivative. Inhibitory activity was highest under mildly acidic (pH 6.0) as opposed to neutral conditions. Fatty N-acylamino acids specifically inhibited production of hemolysin (listeriolysin O) by Listeria monocytogenes. The results suggest that fatty N-acylamino acids may have some potential use as multi-functional food additives.