New Engineered Approaches for Recovering Disperse Populations of Low-tolerance Pathogens from Food

<p>NON-TECHNICAL SUMMARY: <br/>In recent years there have been numerous high profile incidents involving food-borne pathogens which have had devastating impacts not only on public health but on consumer confidence in the safety of foods, and consequently highly adverse effects on the economic viability of the implicated agricultural sectors. Primary examples are the widespread 2010 Salmonella outbreak from contaminated eggs in Iowa, the 2011 lethal E. coli O104 outbreak in Europe and the 2012 Listeria outbreak from melons. Surveillance and detection of disease organisms on food are key factors for preventing disease, and numerous technologies have become available to enable rapid detection. However, disease is usually caused by trace quantities of the pathogenic organisms which require long periods of enrichment to enable detection. Simple methods for isolating disease
organisms from food are required to ensure that rapid screening and detection is effective. The overall goal of this project is to develop and apply transformative technologies including nanoparticle assisted biofilm disruption and electroflotation to enhance the rapid recovery of multiple pathogens including Salmonella, E. coli, Campylobacter, Listeria and other food-borne pathogens from food. Achievement of this goal will enable more reliable rapid detection of these pathogens from food mitigating risk to consumers, and producing the potential ancillary benefits of generating new approaches to effectively decontaminate food. As model organisms and commodities, we will specifically study the recovery of E. coli and Salmonella from leafy green vegetables, poultry, and milk.

<p>APPROACH: <br/>To complete the objectives of this project, the project directors will work with students to develop specific hypothesis based research projects and/or design projects, specifically focusing efforts on the following: 1) screening of different functionalized nanoparticles to find those effective at disrupting mature biofilms of model pathogenic bacteria; 2) study of the mechanisms and interactions of nanoparticle with biofilms; 3) engineer patterning and surface coating methods suitable for fabrication of inexpensive, mass produced, corrosion resistant microelectrode arrays; 4) study the effect of electrical and chemical conditions on the effectiveness of electroflotation-based recovery of suspended bacteria particles, and on the integrity of the captured particles and downstream detection reactions; 5) investigate the interactions between nanoparticle
assisted biofilm disruption, other physico-chemical conditions, and electrolysis conditions for the recovery of viable and detectable pathogen particles; 6) develop an automated, inexpensive, and disposable platform for rapidly isolating bacteria from food surfaces, rinsates, and wash waters. To promote technology transfer, we will also work with extension agents to develop workshops and other training opportunities for commercial farmers and food processors as new technologies and improved knowledge/ practices become available. Evaluation of the project will primarily be tied to achievement of the desired outcomes and milestones, specifically: 1) Identification of safe nanoparticle chemistries and morphologies that are effective at dislodging bacteria in biofilms to facilitate downstream recovery and detection, and quantification of the improvement in recovery compared to controls. 2)
Development of simple, highly scalable production systems to manufacture corrosion resistant microelectrode arrays for electrolysis. 3) Development of a portable, disposable cartridge based system for pathogen recovery that can be used by unskilled laborers in the field or processing plant. 4) Demonstration that new technologies can enable detection of regulatory limits for trace contaminations of pathogenic organisms when used to prepare samples for standard rapid molecular diagnostics such as PCR."