Antimicrobial Effect of Chitosan Coating Prepared by Neutral Electrolyzed Water against Inoculated Escherichia coli O157:H7 on Rainbow trout fillets

Background and Objectives: Nowadays, to avoid the use of synthetic preservatives, which do more harm than good, numerous studies are currently focused on using natural ingredients to enhance food product quality and shelf life. Since no study has been conducted on combining coatings with electrolyzed water containing natural antimicrobial compounds, the present study has innovation and priority. In the present study, the effect of chitosan coating prepared through Neutral Electrolyzed Water (NEW) on inhibiting the growth of Escherichia coli O157:H7 inoculated in rainbow trout fillet over 12 days at 4 ˚C was examined. Material and Methods: Fish samples were allocated into six groups following inoculation with E. coli O157:H7 (final concentration: ~ 105 CFU/g). Treatments included control (CON), distilled water (DW), neutral electrolyzed water (NEW), chitosan 2% (CH), chitosan coating prepared by neutral electrolyzed water (CH/NEW), and neutral electrolyzed water followed by chitosan (NEW+CH). Treatments were kept at low temperature (refrigerator) and counting bacteria was done on 0, 1st, 3rd, 6th, 9th, and 12th days. Data analyses were done through repeated measure ANVOA and Bonferroni post hoc tests. Results: As indicated by the findings, the reduction rate of EW, CH, CH+WE, and CH/EW samples were 1.04, 1.45, 2.01, and 2.02 log CFU/g compared with the CON, respectively. The highest reduction rate was observed in the CH/NEW sample, due to the antimicrobial activity of chitosan and neutral electrolyzed water. Conclusion: Chitosan coating can be combined with NEW in fish to increase the safety against pathogenic bacteria and E. coli O157:H7. Therefore, it can suggest the use of these natural antimicrobial compounds in the food industry.