Abstract
Most cases of microbial food contamination may be caused by cross-contamination at food processing stage. In this study, application of electrolyzed water for pre-cut vegetables was examined for bacterial control at their processing stage. The authors previously reported basic research on enhanced bactericidal effect by electrolyzed water on pre-cut vegetables. Based on the previous report, this study aimed for advanced experiment considering actual field applications and for examination of the resulting effects. In addition to microbial food contamination, chemical contamination was also studied. The rinsing effect of electrolyzed water was examined for the purpose of reducing residual pesticide used for cultivation. To establish an effectual washing process in actual applications, a washing tank was installed in a pre-cut vegetable processing plant, and routine bacterial counting was performed. As the result of preservation study on the green onion treated in the washing tank, 5°C storage was more effective than room temperature or 20°C storage in controlling bacterial growth. Before the washing tank was installed, bacteria attached to green onion varied to some degree but counted 105-106CFU/g for total bacteria and 101-105CFU/g for total coliforms. The washing tank treatment successfully reduced the bacterial count to 104-106CFU/g for total bacteria and negative- 104CFU/g for total coliforms. A commercial pesticide was used to determine the effect of electrolyzed water in rinsing residual pesticide. Mixture with acidic electrolyzed water resulted in reducing detection of an organic phosphorus pesticide Phenthoate™. In a model experiment, a combined treatment with hot alkaline electrolyzed water and cold acidic electrolyzed water was most effective. The results suggested that electrolyzed water might be effective in rinsing residual pesticide.
