Title: Influence of ethylenediaminetetraacetic acid (EDTA) on the bactericidal activity of fatty acids Authors
Submitted to: International Journal of Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 26, 2011
Publication Date: July 28, 2011
Citation: Hinton Jr, A., Ingram, K.D. 2011. Influence of ethylenediaminetetraacetic acid (EDTA) on the bactericidal activity of fatty acids. International Journal of Poultry Science. 10:500-504. Interpretive Summary: Fatty acids can be used to make soap-like solutions that can be used to kill bacteria on poultry meat. In these experiments, the effect of ethylenediaminetetraacetic acid (EDTA) on the ability of these fatty acids to kill bacteria isolated from poultry meat was examined. Solutions of four fatty acids were prepared, and the solutions were supplemented with three concentrations of EDTA. The mixtures were then placed in holes that had been punched in agar media containing the test bacteria. Agar plates were then incubated for 1-2 days to allow the bacteria to grow in the agar. The ability of the fatty acids solutions with EDTA to kill the bacteria was determined by measuring the size of the zones with no bacterial growth around the agar holes filled with the solutions. Results of the experiments indicated that larger zones of inhibition of bacterial growth were generally produced by fatty acid solutions containing higher concentrations of EDTA. EDTA probably increases the ability of fatty acids to kill bacterial by weakening the bacterial cell walls. Findings from these studies indicate that adding EDTA to fatty acid solutions may make these solutions more effective in reducing the number of harmful bacteria found on processed chicken meat sanitized with these solutions.
Technical Abstract: The effect of ethylenediaminetetraacetic acid (EDTA) on the bactericidal activity of alkaline salts of fatty acids was examined. A 0.5 M concentration of caproic, caprylic, capric, and lauric acids was dissolved in 1.0 M potassium hydroxide (KOH), and then supplemented with 0, 5, or 10 mM of EDTA. The pH of the solutions was adjusted to 11.0 with citric acid. Aliquots of FA-KOH-EDTA were added to wells in agar media 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 then incubated aerobically at 35oC for 24 h, except for C. jejuni plates which were incubated microaerophilically at 42oC for 48 h, and then zones of inhibition around the agar 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 were inhibitory towards all isolates, and supplementing both mixtures with EDTA produced larger zones of inhibition of A. calcoaceticus, C. jejuni, Salmonella Typhimurium, and S. simulans. Also, supplementing lauric acid-KOH with EDTA produced larger zones of A. hydrophila, E. faecalis, and P. fluorescens. Findings from these studies indicate that the addition of EDTA to formulations of FA-KOH may increase the ability of these sanitizers to reduce microbial contamination of poultry processing operations.