Development of biocontrol agents against Listeria monocytogenes in dairy production

PI: Tu-Anh Huynh


Huynh is an assistant professor of food science at UW–Madison. Her research interests include bacterial signaling mechanisms mediating growth, stress response and virulence.

Listeria monocytogenes (Listeria) is a prominent foodborne pathogen of particular concern in the dairy industry. Listeria is ubiquitous in dairy farms and easily contaminates contaminates dairy products. Due to its resilience to many stresses encountered during food processing, and the ability to form biofilm on different materials, Listeria is extremely difficult to eradicate in dairy processing plants. Adding to the complexity of controlling Listeria, there is an increasing market demand for bio-preservatives in food, but those products must be both efficacious and compatible with sensory quality. A long-term goal of our research is to develop biocontrol agents against Listeria in dairy products and dairy processing facilities. Upon examining the microbiota of wooden boards used for cheese ripening, we identified at least three bacterial species that inhibit Listeria. Using these bacteria, we will develop: i) protective cultures and ii) natural antimicrobials against Listeria that are suitable for dairy production. For each application, we will design single and mixed-species formulations, and comprehensively evaluate them for Listeria inhibition in laboratory cultures and on cheese ripening board surface. Our study will generate both immediate outcomes and long-term impacts. One, we will identify protective cultures and natural antimicrobials suitable cheese ripening surfaces. Two, inhibition data for each biocontrol formulation will inform future optimization for a range of dairy products and applications. Finally, we will purify and identify antimicrobials produced by the protective cultures, and future studies will modify them for desired efficacy and shelf-life stability.

John Lucey