Fruit and Vegetable Washing (ORP)

This problem of fruit and vegetable decontamination occurs on a larger scale when the produce is first harvested at the farm or when it arrives at a processing facility.  In order to remove dirt and other materials from the produce, these fruits and vegetables must first be washed.  Because agriculture uses a great deal of water as it is, and water can be expensive for farmers, water used in fruit and vegetable washing is often recycled.  In this recycling, contaminants can be distributed throughout the produce. 

This is where measuring the ORP (Oxidation Reduction Potential) of the water can benefit both large and small fruit and vegetable growers, as well as the average homeowner.  The higher the ORP value, measured in millivolts, the more likely the water being tested can oxidize contaminants, thus reducing any harm that may come from them.  For instance, an ORP value of greater than +650 mV has been shown to kill E. coli and Salmonella in a few seconds.  A similar ORP value can predict that the water may kill spoilage yeast and some forms of fungi in a few minutes.  Thus, a farmer or other agricultural professional could determine the likelihood that the water they are using to clean their produce will be effective in decontamination. 

If a farmer finds that their water has a low ORP value, they can then take steps, such as chlorination or ozonation of the water, to remedy the situation. 

Source: Trevor V. Suslow. “Using Oxidation Reduction Potential (ORP) for Water Disinfection Monitoring Control and Documentation.” University of California Agriculture and Natural Resources. UC Good Agricultural Practices. http://ucce.ucdavis.edu/freeform/UC_GAPs/documents/Water_Disinfection1892.pdf.

Author: Ryan McMillen, Ph.D.