Influence of Ethylenediaminetetraacetic Acid (EDTA) on the Ability of Fatty Acids to Inhibit the Growth of Bacteria Associated with Poultry Processing

Abstract

The effect of Ethylenediaminetetraacetic Acid (EDTA) on the bactericidal activity of Fatty Acids (FA) was examined. A 0.5 M concentration of caproic, caprylic, capric, or lauric acid in 1.0 M Potassium Hydroxide (KOH) was supplemented with 0, 5, or 10 mM of EDTA and adjusted to pH 11.0 with citric acid. FA-KOH-EDTA was added to wells in agar seeded with 10⁶ cfu/ml of Acinetobacter calcoaceticus, Aeromonas hydrophila, Campylobacter jejuni, Enterococcus faecalis, Escherichia coli, Listeria monocytogenes, Pseudomonas fluorescens, Salmonella typhimurium, or Staphylococcus simulans. Agar plates were incubated aerobically at 35°C for 24 h, except for C. jejuni plates which were incubated microaerophilically at 42°C for 48 h and zones of inhibition around the wells were measured. Results indicated that although caproic acid-KOH inhibited growth of C. jejuni only, caproic acid-KOH supplemented with EDTA produced significantly (p<0.05) larger zones of C. jejuni as well as zones of inhibition of A. calcoaceticus, E. faecalis and P. fluorescens. Caprylic acid-KOH produced zones of inhibition of all isolates except A. calcoaceticus, L. monocytogenes and S. simulans, but supplementation with EDTA produced zones of inhibition of the 3 isolates in addition to increases in the size of zones of inhibition of E. faecalis and Salmonella Typhimurium. Capric acid-KOH and lauric acid-KOH inhibited all isolates and supplementing both mixtures with EDTA generally produced larger zones of inhibition. Findings indicate that the addition of EDTA to formulations of FA-KOH may increase the ability of these sanitizers to reduce contamination of poultry processing operations.