Electrochemical disinfection: An efficacy treatment to inactivate E. coliO157:H7 in process wash water containing organic matter
Posted: October 26th, 2011 - 10:18am
Source: Food Microbiology
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 ofEscherichia 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.
► This paper is the first dealing with the study (including modelling) of the inactivation of foodborne pathogens in model fresh-cut produce process water by electrochemical disinfection. Contributions include: (1) Data on how different levels of organic matter affect the performance of the electrochemical disinfection process in presence of low and high levels of chloride ion; (2) Interpretation of the disinfection process based on the suitable models. In this study, Escherichia coli O157:H7 has been used as a model, due to the relevance of this foodborne pathogen in the fresh-cut products. Therefore, the results showed in this research article brings valuable information about the effectiveness of alternative disinfection treatments, such as BDD electrodes, in eliminating E. coli O157:H7 contamination during fresh-cut produce processing.