Summary of Awards to Date

Practical application of superheated steam to harvesting, processing, and produce packing tools and equipment

Date

Jan. 1, 2022 - Dec. 31, 2023

Amount Awarded

$396,178.00

Investigator

Abby Snyder, Ph.D.
Cornell University

Co-Investigator(s)

V.M. Balasubramaniam, Ph.D.

Summary

Pathogens can contaminate environmental surfaces in produce handling operations. The industry uses sanitation programs to clean these surfaces and prevent product contamination. Highly effective sanitation procedures reduce the likelihood that pathogens will cross-contaminate products. In facilities that do not use water in their sanitation programs, tools like brushes and rags are used to clean. No-rinse sanitizers are sometimes used as well, but they cannot be used in organic operations. Superheated steam is a novel surface sanitizer that can kill pathogens on environmental surfaces. It is sometimes referred to as “dry steam” because it does not leave moisture or condensation on surfaces, making it a viable option for dry produce facilities. This project is designed to evaluate superheated steam use under industry relevant conditions. We will not only determine how well it works, but we will assess other key performance indicators including cost, range of appropriate applications, and the effect of extended use on equipment wear-and-tear and change to ambient relative humidity. This project will provide industry with the tools to comprehensively assess tradeoffs in superheated steam implementation. These resources will help improve the design of sanitation programs and enhance control over pathogen cross-contamination.

Technical Abstract

Superheated steam (SHS) represents an alternative to conventional dry sanitation strategies (physical removal and spot-cleaning with sanitizer, or intermittent wet cleaning, etc.) utilized in dry produce handling operations. There is limited data to support the efficacy of these conventional dry sanitation strategies in providing equivalent control over microbial hazard removal or inactivation when compared to wet sanitation. Additionally, organic operations frequently rely on a water rinse step following sanitizer application to remove residues, which is not feasible using exclusively dry sanitation methods. SHS represents an energy and water efficient alternative to sanitation across food operations, but because it does not introduce moisture or condensation on equipment surfaces, its application to the treatment of dry produce handling surfaces is of growing interest.

We have a current USDA Innovative Manufacturing Technology grant to optimize the use of SHS as a surface sanitizer in dry food manufacturing plants (nuts and nut butters, bakeries and grain products, dairy powders). Our current project includes evaluation of efficacy against vegetative bacterial pathogens, sporeformers, and patulin producing molds, as well as efficacy trials of this technology on a commercial scale. Here, we propose leveraging that existing equipment infrastructure and expertise to address issues germane to the produce industry by expanding experiments to include treatments to materials specific to the produce industry, like wood and fabric (e.g., nylon) harvesting bins and picker bags. This will allow us to estimate inactivation kinetics across empirical surface features (surface roughness, hydrophobicity, thickness, organic vs inorganic, penetration depth, thermal properties of the treated material) so that outcomes can be extrapolated to other surfaces besides those tested. Moreover, we will expand this work to consider practical application in production environments, including other key performance indicators beyond bench-scale microbial testing. This includes the change to ambient relative humidity (RH) in enclosed spaces based on size, ventilation, and air handling; assessment of equipment damage under extended use of SHS; operator safety parameters and OSHA compliance; and evaluation of the industry’s willingness to pay for enhanced sanitation control.

Results from these objectives will be used in the development of data-driven resources that support industry decision making around SHS implementation. These tools will allow industry to comprehensively assess the KPIs for SHS technologies that take into consideration, not just efficacy, but important tradeoffs in commercial application.