Recipient Organization
VIRGINIA POLYTECHNIC INSTITUTE
(N/A)
BLACKSBURG,VA 24061
Performing Department
(N/A)
Non Technical Summary
Biofilms containing pathogenic bacteria can persist on food contact surfaces (FCS) for years, causing repeated contamination of food products. This is a major challenge for food safety, impacting not only the food processing sector but also public health, the economy, and the environment. While routine cleaning can help mitigate this issue, its efficacy declines on surfaces with nooks and crannies, conveyor belts and rubber gaskets, where biofilms may find shelter. As a result, harmful bacteria such as Listeria monocytogenes and Salmonella enterica can evade cleaning processes and lead to foodborne illness outbreaks, placing significant burdens on both healthcare systems and the food industry. The long-term goal of this project is to enhance food safety by applying mechano-bactericidal (MB) nanopatterns found in nature (e.g., cicada wings) to FCS through practical nanofabrication methods. Unlike traditional chemical approaches, these MB nanopatterns inactivate bacteria by physically rupturing their cells, without releasing biocides into the surrounding food. This offers a safer and more sustainable approach to controlling bacterial contamination on FCS. Initially, in this Seed project, we aim to develop nanofabrication methodologies to create MB nanopatterns on flat stainless steel (SS) and gasket polymer (GP) surfaces. These nanopatterned surfaces will then be evaluated for their antimicrobial efficacy against key foodborne pathogens, including Listeria and Salmonella, in model systems as well as real food matrices.The project has three main goals: (1) Develop practical methods to create bacteria-killing surface coatings using stainless steel and gasket polymers; (2) Test how well these surfaces can kill harmful bacteria like Listeria and Salmonella; and (3) Evaluate how durable these surfaces are, including their chemical resistance, mechanical strength, and how easy they are to clean. If successful, this project could provide a foundation for applying these physics-based bacteria-killing surfaces to more complex equipment used in food processing, such as conveyor belts and rubber gaskets.
Animal Health Component
20%
Research Effort Categories
Basic
40%
Applied
20%
Developmental
40%
Goals / Objectives
Biofilms containing pathogenic bacteria may persist on food contact surfaces (FCS) for years, causing repeated contamination of food products. While cleaning can mitigate this issue, its efficacy declines over surfaces with nooks and crannies where biofilms may be sheltered. The long-term goal of this project is to apply mechano-bactericidal (MB) nanopatterns found in nature (e.g., cicada wings) to FCS via practical nanofabrication methods. Notably, MB nanopatterns inactivate bacteria by rupturing cells physico-mechanically, without releasing biocides into adjacent food matrices. To start, in this Seed project, we aim at developing nanofabrication methodologies to create MB nanopatterns on flat stainless steel (SS) and gasket polymer (GP) surfaces and evaluate their antimicrobial efficacy. This will lay the groundwork for direct modification of 3D parts with curved surfaces, such as metal mesh conveyor belts and various polymeric gaskets. Our central hypothesis is that MB nanopatterns created on stainless steels and gasket polymers are effective against Listeria monocytogenes (Gram+) and Salmonella enterica (Gram-), two persisters in various food processing/service environments, and that cleaning can "unmask" the MB nanopatterns by removing killed bacterial cells/debris for maintaining bactericidal efficacy over repeated exposure.Obj. I: Develop practical nanofabrication methodologies to generate MB-FCS with SS and GPObj. II: Assess the antimicrobial efficacy of MB-FCS against Listeria and SalmonellaObj. III: Evaluate chemical resistance, mechanical stability, and cleaning efficiency of MB-FCS
Project Methods
The following paragraphs break down how the results will be ananlyzed, evaluated, or interpreted by the major objectives of the project.Obj. I: Develop practical nanofabrication methodologies to generate and control MB nanotopographies on stainless steel and gasket polymers.To achieve this objective, we will develop and optimize nanofabrication methodologies for generating and controlling microbicidal (MB) nanotopographies on stainless steel and gasket polymers. The methods for fabrication will include electrochemical etching and nanoimprint lithography. Characterization of the nanoengineered MB surfaces will involve topographicalcharacterization using tools like scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact angle measurements, as well as surface chemistry characterization using tools such as Attentuated Total Reflectance - Fourier Transform Infrared (ATR-FTIR), X-ray Photoelectron Spectroscopy (XPS), and X-ray diffraction spectroscopy (XRD). Statistical analysis will be performed to evaluate the uniformity and repeatability of the produced structures. Success will be measured by comparing the produced nanostructures against predefined criteria for morphology, feature dimensions, and reproducibility.Obj. II: Assess the antimicrobial mechanism and efficacy of MB-FCS against Listeria monocytogenes and Salmonella entericaTo evaluate the antimicrobial mechanism and efficacy of MB-FCSagainst Listeria monocytogenes and Salmonella enterica, we will conduct a series of microbiological assays. These will include bacterial adhesion and viability tests using plate counting methods as well as confocal microscopy. The unique aspect of our confocal approach is the use of live/dead/ROS staining to not only differentiate live from dead, but also provide quantifiable information on the oxidative stress the MB-FCS exert on the adherent cells. Results will be statistically analyzed using ANOVA to determine significant differences between treated and untreated samples.Obj. III: Evaluate chemical resistance, mechanical stability, and cleaning efficiency of MB-FCS.The third objective will evaluate the chemical resistance, mechanical stability, and cleaning efficiency of MB-FCS. Chemical resistance testing will involve exposing the coated surfaces toacid (0.1 M hydrochloric acid), alkaline (0.1 M sodium hydroxide), as well as commercial cleaning products (Topactive DESTM, Topaz MD3TM),and measuring any changes in surface properties using FTIR and SEM and ICP-MS. Mechanical stability will be assessed through shear test and ultrasonication.Cleaning efficiency after initial exposure to bacteria will be tested using simulated food processing conditions, and fouling removal will be quantified using protein and bacterial load assays.Efforts to Cause Change in Knowledge, Actions, or Conditions:Publish 1-2 peer-reviewed articles to disseminate our findings to the broader scientific community.Disseminate knowledge through presentation (talks & posters) at scientific conferences (e.g., IAFP).Share the latest findings from this project with students taking the food engineering course that the PD is developing.Participate in outreach activities through existing university programs at Virginia Tech such as "Hokies for a Day" and "Kids University" to engage younger audiences and foster early interest in food material science and engineering technologies.