INTEGRATION OF MICROBIAL INACTIVATION KINETICS AND GAS TRANSPORT MODELS TO ENHANCE THE ANTIMICROBIAL EFFICACY OF GASEOUS TECHNOLOGIES IN LOW MOISTURE FOODS

The overall goal of this project is to build a substantial interdisciplinary body of knowledge for understanding and improving the efficacy of gaseous technologies (GT) as an intervention method for Salmonella in LMF by addressing the aforementioned limitations. Our long term goals are to:increase confidence in GT as an intervention strategy for foodborne pathogens in LMF thus encouraging adoption by the food industry, andprovide a suite of GT antimicrobial efficacy data along with risks of chemical residues in GT-treated products that can be used by risk assessment studies and policymakers to make informed decisions on utilizing GT.The overall goal will be achieved through four supporting objectives and the associated tasks:Perform head-to-head comparisons of the antimicrobial efficacy of H2O2, and O3 in products representative of LMF categories.Design and fabricate a treatment system with precise controls for process parameters such as gas concentration, relative humidity, temperature, and gas velocity.Develop gaseous inactivation kinetic models for Salmonella spp. in spices, herbs, nuts, and ingredients as functions of gas type and process parameters.Investigate microbiological methods and an appropriate surrogate for Salmonella spp. treated with GT treatments.Develop recovery media and methodology for cells injured by GT.Evaluate Enterococcus faecium NRRL B-2354 as a Salmonella spp. surrogate for GT by comparing its inactivation kinetics.Develop and validate a multiscale modeling framework for simulating the transport of gases in LMF under various process conditions to aid in industrial scale-up of GT technology.Develop a multiscale hybrid mixture theory-based model for understanding the convection and diffusion of gases in LMF matrices.Measure the diffusion coefficient and permeability of gases to solve the model.Integrate the microbial destruction models developed under Objectives 1 and 2 into the multiscale transport model to predict microbial inactivation spatially and temporally.Validate the models using gas pressure and concentration data, and by conducting microbial challenge studies for Salmonella spp. and its surrogate.Conduct chemical analyses for gaseous residues/byproducts and food quality attributes.Perform residue analyses for GT process conditions that provided desired lethality.Evaluate quality attributes of treated samples that achieved sufficient lethality.