Antimicrobial action of octanoic acid against Escherichia coli O157:H7 during washing of baby spinach and grape tomatoes. (November 2019)

• Record Type: Journal Article
• Authors: Zhang, Hongchao; Dolan, Heather Leigh; Ding, Qiao; Wang, Siyuan; Tikekar, Rohan V.
• Is Part Of: Food research international. Volume 125(2019)
• Publication Date: 2019-11
• Subjects: Octanoic acid -- Antimicrobial -- Escherichia coli -- Produce safety -- Membrane damage -- Grape tomato -- Baby spinach; Food -- Analysis -- Periodicals; Food industry and trade -- Periodicals; Food industry and trade -- Canada -- Periodicals; Food Technology -- Periodicals; Food -- Periodicals; Food-Processing Industry -- Periodicals; Aliments -- Industrie et commerce -- Périodiques; Aliments -- Industrie et commerce -- Canada -- Périodiques; Aliments -- Recherche -- Périodiques; Food industry and trade; Canada; Periodicals; Electronic journals; 664.005
• DOI: 10.1016/j.foodres.2019.108523
• Languages: English
• ISSNs: 0963-9969

Abstract

Abstract: We investigated the antimicrobial efficacy of octanoic acid (OA) against Escherichia coli O157:H7 inoculated on the surface of baby spinach and grape tomatoes during simulated washing processes. 3 mM OA at 45 °C achieved >6 log CFU/g reduction from the surface of tomatoes within 2 min. However, washing baby spinach with 6 mM OA at 5 °C resulted in <1 log CFU/g reduction, highlighting the role of surface properties in inactivation efficacy. OA significantly ( p < 0.05) reduced the risk of cross-contamination during washing of spinach as well as tomatoes. Also, total mold and yeast population on surface of spinach was significantly reduced immediately after OA wash and inhibited during following 14 days. Baby spinach and grape tomatoes washed with OA did not cause significant ( p > 0.05) difference in color compared to the control and no residual OA was detected in most cases following rinsing of produce in water. OA at the concentrations above 2 mM and temperature higher than 25 °C induced severe membrane damage along with release of ATP and other intracellular constituents resulting in bacterial death. OA can be an attractive natural decontamination agent for washing fresh produce. Graphical abstract: Unlabelled Image Highlights: Octanoic acid (OA) can inactivate Escherichia coli O157:H7 (>6 log) in 2 min OA was effective in wash water of 5–45 °C and in presence of organic matter OA reduced the risk of cross-contamination during washing of spinach and tomatoes Produce color and microbial quality was not adversely affected by OA treatment OA disrupt E. coli membrane through multiple factors resulting in bacterial death