Advanced Oxidation Processes (AOPs) and Quantitative Analysis for Disinfection and Treatment of Water in the Vegetable Industry

Abstract

Microbiological safety of the fresh-cut produce may not be guaranteed if the quality of wash water is not maintained. Thus, the vegetable processing industry needs to develop alternative sustainable cleaning and disinfection methods in order to reduce cross-contamination and consumption of water throughout the washing process. To assure water quality, chemical and microbial parameters need to be measured based on standard analytical methods. New generation of analytical methods has also emerged to detect priority pollutants, as pharmaceutical compounds, or “emerging pathogens” with antibiotic-resistant genes. Conventional disinfection treatment of wastewaters as chlorination leads to the formation of undesired disinfection by-products and presents limited efficacy against some pathogens. Thus, a more effective and lower-energy demand technology as advanced oxidation processes (AOPs), capable of generating a high amount of hydroxyl radicals upon irradiation, may be considered as alternative. Successful application of solar AOPs has been reported at pilot plants. Predictive design of large-scale AOPs requires the conservation equations of momentum, energy, and mass. These photoactivated processes additionally require the calculation of the local volumetric rate of photon absorption in any position of the system. Quantitative risk assessment studies are required to assess the impact of AOPs as alternative sanitation process and way of enhancing water recycling, on the microbial risk of RTE vegetables. This method is based on four steps: hazard identification and characterization, exposure assessment, and risk characterization. Predictive microbiology models are necessary as not always experimental data are available.