title: Synergistic effects of lactic acid and sodium dodecyl sulfate to decontaminate Escherichia coli O157:H7 on cattle hide sections.
abstract: The objective of this study was to investigate the antibacterial properties of chitosan acetate (CA), sodium dodecyl sulfate (SDS), lactic acid (LA) and their synergism when combined against a nontoxigenic strain of Escherichia coli O157:H7. Treatments that significantly reduced the concentration of E. coli O157:H7 in vitro by more than two logs were further investigated using a cattle hide decontamination model. In vitro treatments included CA (1% chitosan in 1% acetic acid vol/vol), SDS (1% vol/vol), SDS (2% vol/vol), LA (1% vol/vol), CA-SDS combination (1% chitosan in 1% acetic acid vol/vol mixed with 1% SDS vol/vol), and LA-SDS combination in two different concentrations (1% LA mixed with 1% SDS vol/vol, and 1% LA mixed with 2% SDS vol/vol). Butterfield's Phosphate Buffer water was used as a control. The antibacterial effect of 1% CA solution alone and in combination with 1% SDS in vitro resulted in a 1.8 and 1.7 log colony-forming units (CFU)/mL reduction, respectively (p<0.05). Only 1% LA, 1% SDS, 2% SDS and their combinations resulted in a >2 log reduction in E. coli O157:H7. On hide sections, both 1% LA-1% SDS and 1% LA-2% SDS combinations significantly (p<0.05) reduced E. coli O157:H7 concentration by 4.6 and 4.7 log CFU/ cm(2) greater than the control, respectively. There was no significant difference in the antibacterial effect of 1% LA compared to the control, 2% SDS compared to the control, or 1% LA compared to 2% SDS. Hence, the antibacterial efficacy of 1% LA against E. coli O157:H7 on hide sections was significantly enhanced when combined with 1% SDS. Results of this study support the use of low concentration LA-SDS combination as a hide wash to reduce the risk of E. coli O157:H7 contamination.
authors.affiliation: Veterinary Medicine Teaching and Research Center, School of Veterinary Medicine, University of California, Davis, Tulare, California 93274, USA.
authors.forename: Mohamed G
authors.initials: MG
authors.lastname: Elramady
authors.forename: Sharif S
authors.initials: SS
authors.lastname: Aly
authors.forename: Paul V
authors.initials: PV
authors.lastname: Rossitto
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Crook
authors.forename: James S
authors.initials: JS
authors.lastname: Cullor
mesh_terms: D019342:Acetic Acid / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002417:Cattle; D048271:Chitosan / Q000494:pharmacology; D015169:Colony Count, Microbial / Q000662:veterinary; D003666:Decontamination / Q000379:methods; D004357:Drug Synergism; D019453:Escherichia coli O157 / Q000187:drug effects*; D019344:Lactic Acid / Q000494:pharmacology*; D012867:Skin / Q000187:drug effects / Q000382:microbiology*; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D019344:Lactic Acid; D012967:Sodium Dodecyl Sulfate; D048271:Chitosan; D019342:Acetic Acid