Penn State microbiologists receive USDA grant to study biofilms protecting Listeria


The United States Department of Agriculture awarded a $605,000 grant to microbiologists at Penn State’s College of Agricultural Sciences to study how microbial biofilms protect Listeria monocytogenes.

“Microorganisms enclosed in a biofilm produce viscous substances that protect them from the antimicrobial activity of disinfectant chemicals by slowing their penetration into the heart of a biofilm”, Jasna Kovac, Lester Earl and Veronica Casida Career Development Professor of Food Safety and Assistant Professor of Food Science says.

“The formation of biofilms may therefore lead to reduced effectiveness of antimicrobial disinfectants used to inactivate Listeria. This project will investigate the interactions between microorganisms found in fruit packaging environments and Listeria monocytogenes.

Together with Kovac, Luke LaBorde, professor of food science, will use funding from the USDA National Institute of Food and Agriculture to conduct research on the interactions between microorganisms found in food environments. fruit packaging and Listeria monocytogenes.

According to LaBorde, because the role of microbiota from the food processing environment on the survival of Listeria monocytogenes in a biofilm under disinfectant pressure is poorly understood, researchers will assess the ability of the most relevant environmental microbiota found in environments packaging of products to form multi-species biofilms with Listeria monocytogenes.

In this study, Penn State graduate student Laura Rolon is working on four project goals funded by this grant: isolating environmental microbiota and determining its resistance to disinfectants; characterize the genomes of environmental isolates using whole genome sequencing; characterize the biofilm-forming capacity of bacterial families and Listeria monocytogenes in single-family and multi-family assemblages; and characterize the effect of microbial assemblages on the tolerance of Listeria monocytogenes to disinfectant treatment.

According to Rolan, Listeria monocytogenes is particularly dangerous because the pathogen can survive, grow and persist at low temperatures in product processing facilities.

“Biofilms represent a physical barrier that reduces the effective diffusion and antimicrobial action of disinfectants and is thought to increase the tolerance of L. monocytogenes to disinfectants used in food processing facilities,” she said.

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