title: Electrochemical disinfection: an efficient treatment to inactivate Escherichia coli O157:H7 in process wash water containing organic matter.
abstract: The efficacy of an electrochemical treatment in water disinfection, using boron-doped diamond electrodes, was studied and its suitability for the fresh-cut produce industry analyzed. Tap water (TW), and tap water supplemented with NaCl (NaClW) containing different levels of organic matter (Chemical Oxygen Demand (COD) around 60, 300, 550 ± 50 and 750 ± 50 mg/L) obtained from lettuce, were inoculated with a cocktail of Escherichia coli O157:H7 at 10⁵ cfu/mL. Changes in levels of E. coli O157:H7, free, combined and total chlorine, pH, oxidation-reduction potential, COD and temperature were monitored during the treatments. In NaClW, free chlorine was produced more rapidly than in TW and, as a consequence, reductions of 5 log units of E. coli O157:H7 were achieved faster (0.17, 4, 15 and 24 min for water with 60, 300, 500 and 750 mg/L of COD, respectively) than in TW alone (0.9, 25, 60 min and 90 min for water with 60, 300, 600 and 800 mg/L of COD, respectively). Nonetheless, the equipment showed potential for water disinfection and organic matter reduction even without adding NaCl. Additionally, different mathematical models were assessed to account for microbial inactivation curves obtained from the electrochemical treatments.
authors.affiliation: Research Group on Quality, Safety and Bioactivity of Plant Foods, Department of Food Science and Technology, CEBAS-CSIC, P.O. Box 164, Espinardo, Murcia, E-30100, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: López-Gálvez
authors.forename: Guiomar D
authors.initials: GD
authors.lastname: Posada-Izquierdo
authors.forename: María V
authors.initials: MV
authors.lastname: Selma
authors.forename: Fernando
authors.initials: F
authors.lastname: Pérez-Rodríguez
authors.forename: Jean
authors.initials: J
authors.lastname: Gobet
authors.forename: María I
authors.initials: MI
authors.lastname: Gil
authors.forename: Ana
authors.initials: A
authors.lastname: Allende
mesh_terms: D002713:Chlorine; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004203:Disinfection / Q000379:methods*; D055664:Electrochemical Techniques; D019453:Escherichia coli O157 / Q000254:growth & development*; D005506:Food Contamination / Q000032:analysis*; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D018545:Lactuca / Q000382:microbiology; D017711:Nonlinear Dynamics; D014871:Water Microbiology / Q000592:standards
chemical_list: D002713:Chlorine