INFLUENCE OF ETHYLENEDIAMINE‐N,N′‐DISUCCINIC ACID (EDDS) CONCENTRATION ON THE BACTERICIDAL ACTIVITY OF FATTY ACIDS IN VITRO*

Abstract

ABSTRACTThe 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 nine 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.PRACTICAL APPLICATIONSResearch demonstrates that supplementing mixtures of FA‐KOH with EDDS increases the antibacterial activity of these antimicrobial surfactants. Similar results have been produced with FA‐KOH supplemented with ethylenediaminetetraacetic acid (EDTA). However, EDTA is a man‐made, nonbiodegradable chelator, whereas EDDS is a natural biodegradable chelator. Therefore, EDDS may be used as an alternative for EDTA in formulations of FA‐KOH currently being examined as novel sanitizers for decreasing microbial contamination associated with poultry processing. Since EDDS is biodegradable, use of this chelator will not cause concerns of environmental pollution associated with the use of EDTA.