MICROPLASMA-BASED FAR-UVC LIGHT DECONTAMINATION APPROACHES FOR IMPROVING THE SAFETY OF READY-TO-EAT MEAT PRODUCTS

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: EXTENDED
• Funding Source: AFRI COMPETITIVE GRANT
• Reporting Frequency: Annual
• Accession No.: 1027776
• Grant No.: 2022-67017-36291
• Project No.: ILLU-698-648
• Proposal No.: 2021-08158
• Program Code: A1332
• Project Start Date: Jan 1, 2022
• Project End Date: Dec 31, 2024
• Grant Year: 2022

Project Director
Wang, Y.

Recipient Organization
UNIVERSITY OF ILLINOIS
2001 S. Lincoln Ave.
URBANA,IL 61801

Performing Department
Food Science & Human Nutrition

Non Technical Summary
Ready-to-eat food in U.S. retail settings raises numerous food-safety concerns, involving both the presence of foodborne disease organisms, and those organisms' tendency to cross-contaminate, e.g., pass from one food to another. Caused mostly by Listeria monocytogenes bacteria, listeriosis is the foodborne illness with the highest rates of hospitalization and mortality. Deli meats, deli salads, smoked seafood, and cheeses are the U.S.'s highest-risk foods per serving for this potentially fatal disease. In addition, Salmonella strains are commonly found in retail settings. This project will therefore investigate how well a microplasma-based far-UVC system - i.e., a lamp emitting ultraviolet (UV) light with a wavelength of 222 nanometers (nm) - inactivates the above-mentioned bacteria in liquid, on food-contact surfaces, and on deli meats. If it is effective, we will also look at the impact of this treatment on the products' quality, as measured by their color and lipid oxidation. Conventional UVC light, generally at 254 nm, is often used for decontamination, but can potentially lead to eye or skin damage, and is produced by lamps containing toxic mercury. Far-UVC light, on the other hand, does not damage mammalian cells (at the same dosages that do cause damage in the 254 nm case) and requires no mercury. These advantages could enable decontamination while workers and/or consumers are present. As such, the success of this project would provide affordable access to an easy-to-use engineered approach for minimizing cross-contamination and improving overall food safety.

Animal Health Component

0%

Research Effort Categories

Basic

50%

Applied

50%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
501	5010	2020	100%

Knowledge Area
501 - New and Improved Food Processing Technologies;

Subject Of Investigation
5010 - Food;

Field Of Science
2020 - Engineering;

Keywords

deli

far-uvc

food safety

 decontamination

 ready-to-eat meat

 sanitization

Goals / Objectives
The long-term goal of this project is to develop an inexpensive and easy-to-use decontamination technique with which stakeholders can minimize cross-contamination, and thus improve food safety. Its success will ultimately benefit the American people by increasing the availability and accessibility of safe and nutritious food. Our objectives on the way to achieving this goal are as follows:Objective 1: Evaluate the efficacy of microplasma-based far-UVC light for inactivating bacteria in buffer and on food-contact surfaces; Objective 2: Evaluate the efficacy of such far-UVC light for decontaminating real foods; and Objective 3: Evaluate the quality of foods with and without far-UVC light treatment.

Project Methods
Objective 1: Evaluate the efficacy of far-UVC light for inactivating bacteria in buffer and on food-contact surfaces. First, we will use a self-built far-UVC illumination system to investigate the bacterial-inactivation efficacy of far-UVC light when the target bacteria are in liquid buffer, and also measure microbial reactivation following treatment. We will evaluate the bacterial-inactivation efficacy of the far-UVC light system on both gram-positive bacteria such as Listeria monocytogenes and gram-negative ones such as Salmonella strains. Second, various food-contact surfaces (e.g., stainless steel) and common packaging materials (e.g., polyvinyl-chloride film) will be used to evaluate the efficacy of microplasma-based far-UVC light for decontaminating surfaces. An atomic-force spectroscopy and a goniometer will be used to characterize the surface roughness and hydrophobicity of each surface.Objective 2: Evaluate the efficacy of microplasma-based far-UVC light for decontaminating real foods. As compared to buffer and food-contact surfaces, most food is complex and varies in terms of moisture, composition, and texture; and packaging materials differ in terms of how much UV light will pass through them. All these factors may affect the bacterial-inactivation efficacy of far-UVC light. Thus, the primary tasks associated with this objective will include evaluating how well such light can decontaminate packaged and unpackaged real food products, using two of the most popular ready-to-eat deli products, i.e., ham and chicken breast.Objective 3: Evaluate the quality of foods with and without far-UVC light treatment. Color is one of the most important factors affecting consumers' pre-purchase perceptions of meat products. As well as causing color changes, lipid oxidation can negatively affect the quality of deli meats via the formation of rancid flavors and secondary oxidized compounds. Therefore, it is critical to ascertain whether bacteriologically effective dosages of far-UVC light will affect deli meats' color characteristics and lipid oxidation. The several top fluence values from Objective 2, in terms of their log-reduction performance, will be selected for treating the two target deli meats. Then, instrumental colors and lipid oxidation of the treated and untreated meats during storage will be ascertained using a colorimeter and a thiobarbituric acid-reactive substances assay, respectively.

Progress 01/01/23 to 12/31/23

Outputs
Target Audience:The target audience for this project includes but is not limited to an academic community comprising graduate and undergraduate students, engineers, and scientists; government agencies; and the food industry. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The student researchers participating in this project have all received training in handling Risk Group 2 microorganisms and gained basic microbiological-experimentation skills, including culturing, inoculating, and enumerating. Through participation in this project, these students have also commenced learning important research skills including literature review, data analysis, data organization, experimental design, and presentation. Additionally, they have established a research team, convening regularly to analyze their experimental findings and to identify solutions to any obstacles they encounter. How have the results been disseminated to communities of interest?Some of the outcomes of this work were presented at the 2023 Annual Meeting of the International Association for Food Protection. Additionally, the PI has been actively discussing the project's technologies and results with the academic community and other stakeholders, including various existing and potential industrial partners. What do you plan to do during the next reporting period to accomplish the goals?In the next reporting period, we plan to complete 1) our evaluation of the efficacy of microplasma-based far-UVC light for inactivating bacteria on real foods and on food-contact surfaces other than stainless steel; 2) our investigation of such light's bacterial-inactivaction mechanisms; and 3) our measurement of the quality of foods before and after far-UVC light treatment.

Impacts
What was accomplished under these goals? During this reporting period, the team conducted systematic experiments on far-UVC light's bacterial-inactivation efficacies against two of the foodborne bacterial strains most commonly associated with ready-to-eat meat: Listeria monocytogenes and Salmonella Typhimurium. Specifically, we used a self-built microplasma-based far-UVC light system to inactivate the above-mentioned pathogens on a common food-contact surface, stainless steel, and found it capable of achieving approximately 5-log reductions in their density. We then built another microplasma-based far-UVC light system for treating ready-to-eat meat samples, and our preliminary results show that it could inactivate more than 90% of both pathogens on such samples. Additionally, we studied the potential mechanisms whereby far-UVC light inactivates these bacteria, and have commenced preliminary experiments aimed at ascertaining whether/how the quality of ready-to-eat meat is impacted by far-UVC treatment. It is worth noting that the knowledge, experience, and preliminary data gained from this project also helped the PI strengthen a collaborative proposal (in which they serve as a co-PI) to the Department of Energy for research on developing advanced far-UVC modules for enhancing food safety. That proposal has now been funded.

Publications

• Type: Journal Articles Status: Accepted Year Published: 2023 Citation: Jin, Z., Zhao, F., Li, L., Wang, Y.-C. (2023). Tribo-sanitizer: A portable and self-powered UV device for enhancing food safety. Nano Energy, 115, 108675.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2023 Citation: Kim, S. R., Miura, M., Jin, Z., Wang, Y.-C. Far-UVC light for inactivating foodborne pathogens in a liquid medium and on food-contact surfaces. International Association for Food Protection annual meeting, July 16-19, 2023.

Progress 01/01/22 to 12/31/22

Outputs
Target Audience:The target audience for this project is an academic community comprising graduate and undergraduate students, engineers, and scientists. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The student researchers participating in this project have all received training in handling Risk Group 2 microorganisms and gained experience in basic microbiological experiment skills, including culturing, inoculating, and enumerating. They have also formed a research team that meets regularly to discuss their experimental results and establish solutions to any challenges they have encountered. Through participation in this project, these students have also learned important research skills such as literature review, data analysis, data organization, experimental design, and presentation. In short, this project has provided an excellent opportunity for them to develop important skills and gain hands-on experience in developing engineering approaches to address food-safety issues. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?In the next reporting period, we plan to: 1) Complete our evaluation of the efficacy of microplasma-based far-UVC light for inactivating bacteria on food-contact surfaces, 2) Commence our evaluation of the efficacy of far-UVC light for decontaminating real foods, and 3) Commence our evaluation of the quality of foods before and after far-UVC light treatment.

Impacts
What was accomplished under these goals? During this reporting period, our research team built a microplasma-based far-UVC light system and systematically studied its characteristics, such as irradiance, under a variety of operating conditions. We then evaluated the system's decontamination efficacy against foodborne bacteria in a liquid buffer (phosphate buffered saline) and on a common food-contact surface (polyethylene terephthalate) under various operational parameters (Objective 1). Our preliminary results show that our laboratory-scale far-UVC system is capable of achieving five-log reductions in bacteria both in liquid and on surfaces. More research and analyses are underway to systematically understand its efficacy under further operational parameters and its bacterial-inactivation mechanisms. We have also established protocols for our planned experimental decontamination of real food (Objective 2), and will commence such experiments along with the Objective 3 experiments during the next reporting period. It is worth noting that the knowledge, experience, and preliminary data gained from conducting this project have also helped the PI strengthen a proposal to Illinois Specialty Crop Block Grant Program for research on whether/how far-UVC light systems can be used to decontaminate specialty crops. That proposal has now been funded.

Publications