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Functionalized Lipid Nanoparticles for Pathogen Inactivation in Cut Leafy-Greens and Other Minimally Processed Vegetables


The long term goal of the project is to decrease the incidence of outbreaks through the design and construction of lipid-base antimicrobial delivery nanoparticulate system for elimination of pathogens that become internalized into vascular tissue or that attach to cut surfaces as a consequence of minimal processing operations in leafy-greens and other cut vegetables.<P> In order to achieve the overall goal, the following five supporting objectives are proposed: <ol> <LI> Investigate the In vitro effectiveness of essential oils encapsulated into lipid nanodispersions for the inactivation of microbial pathogens in model liquid and solid media.<LI> Evaluate In situ internalization and attachment of pathogens to cut or damaged vegetable tissue, as well as antimicrobial activity of lipid nanodispersions. <LI> Design and construct functionalized lipid nanodispersions which target pathogens in cut vegetables and exhibit enhanced antimicrobial activity. <LI> Investigate the attachment/internalization behavior of functionalized and non-functionalized lipid nanoparticles in vegetable tissue <LI> Evaluate the effectiveness of functionalized lipid nanoparticles In vitro and In situ using cut leafy greens and other minimally processed vegetables. </ol>Expected outputs from this project include two graduated Master's students. The results and findings will be presented in National Scientific Meetings and published in scientific journals.

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Non-Technical Summary: Recent outbreaks associated to the consumption of raw or minimally processed vegetable products such as lettuces, baby spinach and melons that have resulted in several illnesses and a few deaths call for urgent actions aimed at improving the safety of those products. The long term outcome of this project is to decrease the number of outbreaks and illnesses caused by consumption of raw or minimally processed vegetable products in the US. Particular interest of this project is placed on those harmful microorganisms that during processing enter the intermediate layers of tissue and which because of that cannot be removed during washing operations. We propose to create a dispersion of lipid nanoparticles containing antimicrobials that would selectively bind to harmful microorganisms. A team of four researchers from Food Science, Biology, Material Science and Horticulture will work together to reach the long term goal. Activities for this project include the development of a production protocol and understanding of the lipid nanoparticles efficacy to eliminate harmful microorganisms in model systems as well as in cut vegetables such as romaine lettuce, spinach and celery. <P> Approach: The project will be performed over the course of three years. During year one characterization of non-functionalized lipid nanodispersions as well as their efficacy for the In vitro inactivation of pathogens will be investigated. Bioluminescent strains of pathogens will be used to monitor inactivation and the results confirmed by traditional plating techniques. During year two the efficacy of the most efficient systems will be tested In situ using cut vegetables to simulate minimal processing operations. At the same time, nanoparticle functionalization studies will be conducted with the goal of increasing the efficacy of the antimicrobial delivery systems. Experiments aimed to investigate the attachment and internalization potential of bioluminescent pathogens and functionalized and non-functionalized lipid nanodispersions will be conducted in years 1, 2 and 3. Finally, experiments that evaluate In vitro and In situ efficacy of functionalized lipid nanodispersions will be performed during the second half of the project. Knowledge generated through this project will be disseminated by presentations in National Scientific Meetings as well as through publications in recognized scientific journals. Graduate and undergraduate students will learn by doing while conducting the experiments and through biweekly meetings with the project directors students will clarify gaps in knowledge.

San Martin, Fernanda
Purdue University
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