title: Control of pathogens in biofilms on the surface of stainless steel by levulinic acid plus sodium dodecyl sulfate.
abstract: The efficacy of levulinic acid (LVA) plus sodium dodecyl sulfate (SDS) to remove or inactivate Listeria monocytogenes, Salmonella Typhimurium, and Shiga toxin-producing Escherichia coli (STEC) in biofilms on the surface of stainless steel coupons was evaluated. Five- or six-strain mixtures (ca. 9.0 log CFU/ml) of the three pathogens were separately inoculated on stainless steel coupons. After incubation at 21 °C for 72 h, the coupons were treated for 10 min by different concentrations of LVA plus SDS (0.5% LVA+0.05% SDS, 1% LVA+0.1% SDS, and 3% LVA+2% SDS) and other commonly used sanitizers, including a commercial quaternary ammonium-based sanitizer (150 ppm), lactic acid (3%), sodium hypochlorite (100 ppm), and hydrogen peroxide (2%). The pathogens grew in the biofilms to ca. 8.6 to 9.3 log CFU/coupon after 72 h of incubation. The combined activity of LVA with SDS was bactericidal in biofilms for cells of the three pathogens evaluated, with the highest concentrations (3% LVA+2% SDS) providing the greatest log reduction. Microscopic images indicated that the cells were detached from the biofilm matrix and the integrity of cell envelopes were decreased after the treatment of LVA plus SDS. This study is conducive to better understanding the antimicrobial behavior of LVA plus SDS to the foodborne pathogens within biofilms.
authors.affiliation: Center for Food Safety, College of Agricultural and Environmental Sciences, University of Georgia, 1109 Experiment Street, Griffin, GA 30223, USA.
authors.forename: Dong
authors.initials: D
authors.lastname: Chen
authors.affiliation: Center for Food Safety, College of Agricultural and Environmental Sciences, University of Georgia, 1109 Experiment Street, Griffin, GA 30223, USA.
authors.forename: Tong
authors.initials: T
authors.lastname: Zhao
authors.affiliation: Center for Food Safety, College of Agricultural and Environmental Sciences, University of Georgia, 1109 Experiment Street, Griffin, GA 30223, USA. Electronic address: mdoyle@uga.edu.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Doyle
mesh_terms: D001419:Bacteria / Q000187:drug effects*; D018441:Biofilms / Q000187:drug effects*; D015169:Colony Count, Microbial; D003666:Decontamination / Q000379:methods*; D004202:Disinfectants / Q000494:pharmacology; D005516:Food Microbiology / Q000379:methods*; D007982:Levulinic Acids / Q000494:pharmacology*; D008089:Listeria monocytogenes / Q000187:drug effects; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology*; D012973:Sodium Hypochlorite / Q000494:pharmacology; D013193:Stainless Steel; D013501:Surface-Active Agents / Q000494:pharmacology
chemical_list: D004202:Disinfectants; D007982:Levulinic Acids; D013501:Surface-Active Agents; D013193:Stainless Steel; D012967:Sodium Dodecyl Sulfate; D012973:Sodium Hypochlorite; C032246:levulinic acid
keywords: Biofilm; Escherichia coli; Levulinic acid; Listeria; Salmonella; Sodium dodecyl sulfate