Using Oxidation Reduction Potential (ORP) for Water Disinfection Monitoring, Control and Documentation

Using Oxidation Reduction Potential (ORP) for Water Disinfection Monitoring, Control and Documentation

Large volumes of water are commonly used during the postharvest handling and processing of minimally processed fruits and vegetables. Economic considerations and wastewater discharge regulations make water recirculation a common practice in the industry. Few practices have the capacity of water recirculation to increase the potential risk of food-borne illness by readily distributing a point source contaminant (one lot, one bin, or even one plant) to non-contaminated produce. Disinfection of water is a critical step to minimize the potential transmission of pathogens from a water source to produce, among produce within a lot, and between lots over time. Water-borne microorganisms whether postharvest plant pathogens or agents of human illness can be rapidly acquired and taken up on plant surfaces. Natural plant surface contours, natural openings, harvest and trimming wounds, and handling injuries can serve as points of entry for microbes. Within these protected sites, microbes are unaffected by common postharvest water treatments such as chlorine, chlorine dioxide, ozone, peroxide, peroxyacetic acid, UV-irradiation and other approved treatments. It is essential, therefore, that the water used for washing, cooling, transporting, postharvest drenches, or other procedures be maintained in a condition suitable for the application. The standards for microbial quality of the water increase as product moves from the field to final processing. Accurate monitoring and recording of disinfection procedures is an important component of a sound postharvest quality and safety program during product cooling and processing.