ARS | Publication request: Influence of ethylenediamine-n,n’-disuccinic acid (EDDS) concentration on the bactericidal activity of fatty acids in vitro

Submitted to: Journal of Food Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 10, 2011
Publication Date: September 13, 2011
Citation: Hinton Jr, A., Ingram, K.D. 2011. Influence of ethylenediamine-n,n’-disuccinic acid (EDDS) concentration on the bactericidal activity of fatty acids in vitro. Journal of Food Safety. DOI: 10.1111/j.1745-4565.2011.00307.x.

Interpretive Summary: Fatty acids are soap-like, natural substances that can be used to kill bacteria on poultry meat and in other foods. Ethylenediamine-N,N’-disuccinic acid (EDDS) is also a natural substance that can be added to soaps to increase the cleansing activity of these surfactants. The present experiments examined the ability of mixtures of fatty acids and EDDS to inhibit the growth of bacteria isolated from poultry meat. Solutions of four fatty acids were prepared, and three concentrations of EDDS were added to different aliquots of each fatty acid. 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 EDDS to inhibit growth of the bacteria was determined by the presence of the clear zones with no bacterial growth around the agar holes filled with the solutions. Results of these experiments indicated that larger zones of inhibition of bacterial growth were generally produced by fatty acid solutions containing higher concentrations of EDDS. Findings from these studies indicate that adding EDDS 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 antibacterial activity of mixtures of ethylenediamine-N,N’-disuccinic acid (EDDS) and antibacterial fatty acids (FA) was examined using the agar diffusion assay. Solutions of caproic, caprylic, capric, and lauric acids dissolved in potassium hydroxide (KOH) were supplemented with 0, 5, or 10 mM of EDDS and adjusted to pH 11.0 with citric acid. Wells made in agar media seeded with one of nine bacterial isolates were filled with FA-KOH or FA-KOH-EDDS solutions. After incubation of agar plates, zones of inhibition of bacterial growth around the agar wells were measured. Results indicated that caproic-KOH-EDDS and caprylic-KOH-EDDS inhibited growth of more bacterial isolates than caproic-KOH and caprylic-KOH, respectively. Although, capric-KOH and lauric-KOH produced zones of inhibition of all 9 bacterial isolates, significantly (p < 0.05) larger zones of inhibition were produced by capric-KOH-EDDS and lauric-KOH-EDDS. Findings of this study indicate that mixtures of FA-KOH-EDDS possess greater antibacterial activity than FA-KOH.