Nonthermal Decontamination Of Leafy Vegetable Food Products Using Nanosecond Pulsed Electric Field Exposures

Overall Goal:The overall goal is to decontaminate fresh and fresh-cut leafy vegetables using bipolar nanosecond pulsed electric field (nsPEF) processing to nonthermally inactivate bacteria and yet not damage plant cells.Major Goal 1:The effects of bipolar nsPEF exposure on leaf tissue structure, cell viability, and chemical stability will be assessed and correlated to consumer acceptance parameters of color and texture over time following exposure.Objective 1A: is to measure thermal and electrical properties of spinach and romaine lettuce leaf tissues.Objective 1B: is to use thermal and electrical properties in a simulation to predict PEF exposure distributions and Joule heating within leaf tissues, and to compare predictions with measured temperature changes.Objective 1C:is to measure permeabilization and survival of cells in leaves exposed to PEF treatment.Objective 1D:is to determine mechanical properties and microstructure of spinach and romaine lettuce leaves exposed to PEF treatment.Objective 1E: is to analyze chlorophyll stability of spinach and romaine lettuce leaves exposed to PEF treatment.Major Goal 2:is to determine effectiveness of bipolar nsPEF exposure for microbial inactivation.Objective 2A: is to evaluate and compare the baseline capability of nsPEF exposure to eradicateE. coliandL. monocytogenesin planktonic and biofilm states.Objective 2B: is to evaluate and compare electrosensitization-based lethality of successive nsPEF exposures toE. coliandL. monocytogenesin planktonic and biofilm states.Objective 2C: is to evaluate and compare inactivation susceptibility ofE. coliandL. monocytogenesin planktonic and biofilm states imparted by nsPEF exposures in the presence of bactericidal small molecules including bleach, L-lysine, and acetic acid.Objective 2D: is to measure inactivation of biofilm-stateL. monocytogenesinoculated onto fresh-cut spinach and romaine lettuce leaves using bipolar nanosecond pulsed electric fieldsObjective 2E: is to determine inactivation of co-culturedE. coliandL. monocytogenesin biofilms inoculated onto fresh-cut spinach and romaine lettuce leaves using bipolar nanosecond pulsed electric fields