Surface Decontamination of Fresh, Whole Peaches (Prunus persica) Using Sodium Hypochlorite or Acidified Electrolyzed Water Solutions

Nearly half (45%) of the U.S. peach production is sold through the fresh market sector, making post-harvest disinfectant washing treatments a critical step for reducing surface microorganisms. This study was conducted to determine the effects of various disinfectant washing treatments on the surface decontamination of fresh whole freestone peaches. Minimal application of disinfectant washing treatments (five-second dip) reduced numbers of Listeria innocua recovered from inoculated peaches by 93% (acidified electrolyzed water containing 22 ppm sodium hypochlorite, pH 2.8) or 96% (chlorine containing 22 ppm sodium hypochlorite, pH 8.2) compared to cell counts on unwashed or water-only washed peaches. Increasing the wash time to 40 minutes resulted in a greater reduction in numbers of Listeria innocua recovered from the surfaces of peaches (99.95% and 99.9% for acidified electrolyzed water and chlorine treatments, respectively). All of the washing treatments decreased counts of total aerobic microorganisms on peaches (>92% reduction) when applied for 40 minutes. The results of this study demonstrate that washing peaches reduced but did not completely eliminate surface microorganisms.