Exploiting the food-grade organism Aspergillus oryzae as a biocontrol agent against Listeria monocytogenes in dairy products and cattle

PI: Tu-Anh Huynh

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

Graduate student (pictured above): Yuxing Chen received her bachelor’s degree in food science engineering from South China University. As an undergraduate she developed valuable leadership, laboratory, and analytical skills related to various bacteria. Chen is currently pursuing a master’s degree in food science mentored by Tu-Anh Huynh.

Listeria monocytogenes is a prominent foodborne pathogen of particular concern in the dairy industry. Listeria frequently infects dairy cattle and contaminates the dairy food production chain and is highly resilient to stress. Adding to the complexity of controlling Listeria, there is an increasing consumer demand for natural, “clean-label” antimicrobials, but a major challenge in developing natural antimicrobials is to achieve sufficient efficacy in food. Aspergillus oryzae, a food-grade fungus commonly used in fermentation, produces antimicrobials that potentially kill Listeria in laboratory cultures and contaminated milk. This project aims to develop A. oryzae-derived antimicrobials as biocontrol agents in animal feed, dairy products, and on dairy processing equipment. This project will evaluate the efficacy of A. oryzae extract against diverse Listeria strains of dairy origins, in cheese and wooden cheese ripening surface and will determine if A. oryzae extract interferes with the volatile flavor profiles in treated cheese. Finally, this project will examine how Listeria responds to sub-lethal treatments and adaptive laboratory evolution. The findings of this study will guide formulations of natural biocontrol agents that inhibit and kill Listeria in dairy animal feed, dairy products, and dairy, processing plants.

Jae-Hyuk Yu