Combined Treatment of Aqueous Chlorine Dioxide, Organic Acid, and Blanching for Microbial Decontamination of Wild Vegetables after Harvest

Abstract

To improve the microbiological safety of wild vegetables after harvest, Aster scaber and Cirsium setidens Nakai were treated with combinations of 50 ppm aqueous chlorine dioxide (ClO2)/0.5% citric acid or fumaric acid, and 50 ppm ClO2/0.5% fumaric acid/blanching at 90°C for 2 min. Combined treatment of 50 ppm ClO2 and 0.5% citric acid reduced populations of total aerobic bacteria, yeast, and molds in Aster scaber and Cirsium setidens Nakai by 2.80∼3.64 and 2.02∼2.67 log CFU/g, respectively, compared to those of the control. Combined treatment of 50 ppm ClO2 and 0.5% fumaric acid reduced total aerobic bacteria, yeast and molds populations by 3.62∼3.82 and 2.47∼3.02 log CFU/g, respectively. Based on the results, combined treatment of ClO2 and fumaric acid was more effective in controlling microorganisms in the wild vegetables than either ClO2 or citric acid. In addition, combined treatment of ClO2/fumaric acid/blanching reduced the populations of total aerobic bacteria by 4.59∼5.12 log CFU/g, and populations of yeast and molds were not detected by treatment. These results suggest that combined treatment of ClO2/fumaric acid/blanching is the most effective method for improving microbiological safety of wild vegetables after harvest.Key words: wild vegetable, chlorine dioxide, organic acid, blanching, microbiological safety