Effect of water hardness on the production and microbicidal efficacy of slightly acidic electrolyzed water.

Slightly acidic electrolyzed water (SAEW) has been proved as an effective sanitizer against microorganisms attached to foods. However, its physical properties and inactivation efficacy are affected by several factors such as water hardness. Therefore, in this study the effect of water hardness on SAEW properties were studied. Pure cultures of foodborne bacteria were used in vitro and in vivo to evaluate the inactivation efficacy of the SAEWs produced. Results obtained showed water hardness to be an important factor in the production of SAEW. Low water hardness may result in the necessity of further optimization of production process. In this study the addition of 5% HCl and 2 M NaCl at 1.5 mL/min flow rate was found to be the best electrolyte concentration for the optimization of SAEW production from low hardness water (34 ± 2 mg/L). Furthermore, the results showed that pre-heating was a better approach compared to post-production heating of SAEW, resulting in higher ACC values and therefor better sanitization efficacy.