Effect of acidic electrolyzed water on the microbial counts in shredded vegetables

Abstract

Acidic electrolyzed water (AcEW) is a new disinfectant prepared by electrolyzing dilute sodium chloride solutions. AcEW has a low pH (below 2.7), high oxidizing reduction potential (ORP above + 1100 mV) and available chlorine concentration (ACC, 40-50 ppm). We studied the disinfectant effect of AcEW on five kinds of shredded vegetables. The microbial counts in lettuces, cabbages, carrots and burdocks were reduced from 1/10 to 1/100 of the initial numbers within 10 minuets by soaking the vegetables in AcEW. However, 20 minuets of soaking in AcEW were required for the initial microbial counts in cucumbers to be reduced by 1/10. The appearance of the vegetables did not deteriorate after soaking for 20 minuets in AcEW. The disinfectant effect was not enhanced by prolongation of treatment time. Therefore, soaking shredded vegetables in AcEW for 10-20 minuets is sufficient to disinfect microbes contaminating the surface of the vegetables. Moreover, we compared the disinfectant effects of AcEW and sodium hypochlorite (ACC of about 150 ppm) on shredded lettuces, cabbages, cucumbers, carrots and burdocks. It was found that the disinfectant effect of AcEW was equivalent to that of sodium hypochlorite solution. Unlike sodium hypochlorite solution, which has been used as a disinfectant for shredded vegetables, AcEW is easy to handle and there is little residual chlorine odor. AcEW is therefore a useful substitute for sodium hypochlorite to disinfect shredded vegetables.