Development and Transfer of Disinfection By-products into Fresh and Fresh-cut Produce and Impact on Disinfection Efficacy

<p>NON-TECHNICAL SUMMARY:<br/>Chlorine-containing disinfectants are widely used in the processing of fresh and fresh-cut produce. However, significant knowledge gaps still exist regarding the formation, identities and quantities of disinfection by-products (DBPs) generated as food residues or in the processing water. This project addresses this issue by investigating many conventional and emerging DBPs of concern for their mechanisms of formation and transfer into fresh and fresh-cut produce after chlorine-based disinfection methods (sodium hypochlorite, chlorine dioxide and electrolyzed oxidizing water), and for their impact on the efficacy in inactivating pathogens. <p>Six specific research objectives are included: (1) Improve/develop analytical methods for measuring conventional and emerging DBPs in process water and produce; (2) Prioritize DBPs based on screening of their
concentrations after typical chlorine disinfection for produce; (3) Evaluate the formation of DBPs and impact on microbial inactivation efficacy due to different disinfectants, produce, disinfection conditions and operational parameters; (4) Evaluate the stability and transfer of DBPs in and between water and produce; (5) Elucidate the mechanisms of DBP formation from organic precursors in produce; and (6) Develop effective disinfection strategies of high microbial inactivation efficacy and minimized DBP formation for fresh and fresh-cut produce. Results of this project will be very useful for the produce industry to better understand the risks of food-borne DBPs and develop strategies to improve current sanitation processes. They will also contribute to the long-term sustainability of food production systems by providing safer products, reducing improper usage of hazardous chemical
disinfectants, and reducing contamination in food processing water.
<p>APPROACH: <br/>This project will be conducted primarily as a laboratory-based investigation. Laboratory experiments and research tasks have been carefully designed according to the six specific research objectives as outlined below and will be conducted sequentially to achieve to project goals. The research results and knowledge obtained in this study will be presented in conferences and published in peer-reviewed scientific journals, internet, and Food industry-related newsletters. The research study and results will also be prepared into example case studies and teaching modules and taught in graduate and/or undergraduate courses at the PI's and Co-PI's institutions. Graduate and undergraduate students will be recruited to participate in this research study and receive training.<p>The evaluation plans for the six specific research objectives are described
below: Objective 1: Improve and develop analytical methods for measuring conventional and emerging DBPs in process water and produce Milestones: Establishment of the analytical methods Evaluation Plan: QA and QC valuations of the analytical methods Objective 2: Prioritize DBPs based on screening of their concentrations that can be formed after typical chlorine disinfection for produce Milestones: Screening results on the occurrence of DBPs Evaluation Plan: Evaluate the range and levels of DBPs detected, and adjust the screening test conditions if necessary Objective 3: Evaluate the formation of DBPs and impact on microbial inactivation efficacy due to different types of disinfectant, produce, oxidant dosage, contact time, pH, temperature and ionic composition Milestones: Systematic results on the DBP formation trends influenced by each key parameter Evaluation Plan: Evaluate the
consistency of data and adjust the testing conditions if necessary Objective 4: Evaluate the stability and transfer of DBPs in and between water and produce Milestones: Quantitative sorption and desorption data of DBPs between water and produce Evaluation Plan: Evaluate the consistency of sorption data and adjust the testing conditions if necessary Objective 5: Elucidate the mechanisms of DBP formation from organic precursors prevalent in produce Milestones: Identification of important DBP precursors in produce and suitable representative model compounds Evaluation Plan: Evaluate the range of model compounds selected and investigated, and make necessary modification Objective 6: Develop effective disinfection strategies of high microbial inactivation efficacy and minimized DBP formation for fresh and fresh-cut produce Milestones: Improved disinfection strategies that are lower in DBP
formation but maintain high microbial inactivation efficacy Evaluation Plan: Benchmark comparison to conventional free chlorine disinfection strategies that are commonly used currently.