Contamination Mechanisms of Engineered Nanoparticles in Fresh Produce and Control Strategies During Processing

Our long-term goal is to improve food safety of fresh produce through elucidating fundamental interactions between agriculturally-relevant ENPs, fresh produce, water and equipment surfaces commonly used in commercial processing facilities, as well as through designing effective strategies for the removal of foodborne ENPs. In order to achieve this long-term goal, we designed the following specific objectives in this project, including:1) Investigate the sorption of selected ENPs (nano-Ag and nano-TiO2) to fresh produce (lettuce, spinach, tomato). The principal goal is to determine fundamental mechanisms contributing to the sorption of ENPs by fresh produce under representative scenarios of nanopesticide application or irrigation with ENP-containing water. Particular emphasis will be given to quantifying the contribution of stomata to the internalization of ENPs into leafy greens.2) Evaluate the influence of wash water conditions on ENP sorption to the fresh produce and equipment surfaces. We will investigate the sorption and desorptionbehaviors of ENPs to fresh produce and equipment surfaces under a range of wash water conditions (e.g., sanitizer type, surfactant, organic matter concentration, and temperature).3) Quantify ENP removal efficiency by tracking the transfer and distribution of ENPs among the produce, equipment surfaces, and wash water in an existing pilot-scale processing line. The goal is to find optimal wash water conditions that can be implemented, thereby improving food safety by decreasing the ENP levels in fresh produce.