Disinfection effect of neutral electrolyzed water for shell egg washing

For the sake of developing an effective, safe and no pollution disinfectant to reduce or eliminate food-borne pathogens on shell eggs, the bactericidal activity of neutral electrolyzed water (NEW, pH 6.0-7.5) generated by electrolysis of diluted hydrochloric acid in a non-membrane electrolytic cell for inactivation of Salmonella pullorum, Escherichia coli O157:H7 and artificial inoculated shell eggs (initial logarithm of population of two pathogens on the eggs were approximately 6.19-6.26 log10 (cfu/g) and 6.12-6.19 log10 (cfu/g) respectively) was evaluated. The bactericidal activity of NEW for both of pathogens increased with increasing the available chlorine concentration and treatment time. A 100% inactivation of S. pullorum (initial logarithm of population of pathogen 8.12 log10 (cfu/mL)) and E. coli O157:H7 (initial logarithm of population of pathogen 7.78 log10 (cfu/mL)) was resulted in NEW with available chlorine more than 1.5 and 2 mg/L for 3 min at 20oC, respectively. Temperature had no markedly effect on the bactericidal activity of neutral electrolyzed water. The S. pullorum on the surface of shell eggs was completely killed and E. coli O157:H7 logarithm of counts decreased to less than 1.0 log10 (cfu/g) by NEW containing 12 mg/L available chlorine for 3 min without viable cells in the washing water after treatment. Results indicate that NEW has a great potential to be used as effective disinfectant agent for egg washing.