Bactericidal activity of copper-ascorbic acid mixture against Staphylococcus aureus spp. (May 2020)

• Record Type: Journal Article
• Authors: Gyawali, Rabin; Zimmerman, Tahl; Aljaloud, Sulaiman O.; Ibrahim, Salam A.
• Is Part Of: Food control. Volume 111(2020)
• Publication Date: 2020-05
• Subjects: Staphylococcus aureus -- Copper -- Ascorbic acid -- Vitamin C -- Decontaminating solution -- Bactericidal effect -- Food safety; Food -- Quality -- Periodicals; Food -- Analysis -- Periodicals; Food handling -- Periodicals; Food industry and trade -- Quality control -- Periodicals; Aliments -- Industrie et commerce -- Qualité -- Contrôle -- Périodiques; Aliments -- Qualité -- Périodiques; Aliments -- Analyse -- Périodiques; Hygiène alimentaire -- Périodiques; Food -- Analysis; Food handling; Food -- Quality; Periodicals; Electronic journals; 664.07
• DOI: 10.1016/j.foodcont.2019.107062
• Languages: English
• ISSNs: 0956-7135

Abstract

Abstract: The purpose of this study was to investigate the bactericidal activity of copper (Cu, 10 ppm) and ascorbic acid (AA, 0.3% v/v) mixture against Staphylococcus aureus ( S. aureus ) ATCC 25923 (methicillin-susceptible) and ATCC 700698 (methicillin-resistant) strains. Approximately 5.5 log10 CFU/ml of each strain was individually inoculated into brain heart infusion (BHI) broth containing Cu, AA, and a Cu-AA mixture, and a time-kill assay was conducted to assess the bactericidal activity. In order to determine the efficacy of Cu-AA mixture as a surface decontaminating solution, the cells were first attached to glass slides (~6.5–7.5 log10 CFU per slide) and treated with a Cu-AA mixture for 1 min. The inner membrane permeability of the S. aureus strains was determined by measuring β-Galactosidase activity. Similarly, changes in the protein profile of treated bacterial cells were analyzed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The time-kill study revealed >3.0 log10 CFU/ml reduction in both strains within 24 h of incubation at 37 °C. Attached cells on glass slides were also reduced by > 3.0 log10 CFU per slide after 1 min of exposure to the Cu-AA mixture. The results indicate that the Cu-AA mixture was bactericidal against S. aureus strains and the damage to the inner cell membrane could be attributed to this effect. Graphical abstract: Image 1 Highlights: The presence of Staphylococcus aureus on food contact surfaces is a potential hazard. A mixture of copper (Cu) and ascorbic acid (AA) (vitamin C) kills 99.9% of S. aureus strains. Cu-AA mixture could be a promising substitute for conventional antimicrobial wash solutions. Cu-AA could be used as a novel disinfectant for decontamination of foods and food contact surfaces.