What We Learned from Recent United States Listeriosis Outbreaks




Over the past few years, several listeriosis outbreaks occurred, and novel or atypical food vehicles—cantaloupes, stone fruit, apples, ice cream, frozen vegetables, leafy green salad, etc.—have been identified. A series of research efforts have been performed to fill in the knowledge gaps on the factors that might have contributed to the Listeria contamination of final food products, the survival/growth potential of L. monocytogenes in these novel food vehicles, and the risk associated with Listeria contamination in these foods. Whole genome sequencing (WGS) was used to augment source tracking and investigations of these outbreaks. WGS also greatly enhanced regular surveillance by detecting the persistent and transient contaminations of Listeria in the food processing environment. This seminar will cover these research efforts.


Yi Chen is a research microbiologist at the Center for Food Safety and Applied Nutrition (CFSAN) of the United States Food and Drug Administration. He provides leadership on research activities on the method development and validation for the detection and enumeration of L. monocytogenes and Cronobacter in foods and environments. Chen also leads projects that study the behaviors of L. monocytogenes in various food matrices to elucidate the risk of L. monocytogenes contamination in these foods. He is an expert on whole genome sequencing analysis for surveillance and outbreak response. Recognized as the subject matter expert on L. monocytogenes, he has provided scientific advice for various FDA assignments, outbreak investigations, and laboratory analyses. Chen received his Ph.D. in food science at the Pennsylvania State University in 2007. He currently serves as a member of the Microbial Method Validation Subcommittee of the FDA, co-general referee for AOAC International, and editorial board member for Applied and Environmental Microbiology. 

You can attend this virtual lecture in one of two ways: 

  • By phone at ‪484.301.5404; PIN: ‪106 294 247#


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