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Interaction of resident microbiome and Listeria on pears during cold storage


Listeria monocytogenes can be found in a wide variety of natural and food production environments and has been implicated in multiple fresh produce-related listeriosis outbreaks. Washington leads pear production in the United States with a total of 347,000 tons in 2020. Though fresh whole pears have not experienced an incidence of listeriosis illness or outbreak, multiple recent large-scale recalls and high-profile outbreaks associated with other tree fruits due to potential L. monocytogenes contamination have prompted the pear industry to develop validated interventions and have proactive measures to minimize post-harvest risks. Pear surfaces are colonized by diverse groups of microorganisms and further exposed to microbial contamination during production and processing. The associated resident microbial communities (microbiome) and those introduced at harvest or postharvest handling may influence the persistence of foodborne pathogens on the surface. There is a general lack of knowledge on the fate of Listeria on pears during storage, or the dynamic changes of the pear microbiome over long-term cold storage and the effects of such changes on the survival of Listeria on pears, leaving critical knowledge gaps. The overall goal is to evaluate temporal changes of microbiome and their interactions with Listeria on pears following different agricultural practices and storage regimes using a metagenomic sequencing approach. We will pursue two specific objectives: 1) Examine the fate of Listeria and temporal changes of the resident microbiome on pears and their interactions during long-term cold storage; 2) Evaluate the impacts of organic practices on the microbiome community and persistence of Listeria on pears of the selected varieties during long-term storage. Knowledge obtained will enable us to have a better understanding of the survival of Listeria on pear surfaces and the interactions between Listeria and indigenous microbiota on pear surfaces. These data will lay a foundation for future efforts to develop an organic/natural strategy to control Listeria on pear surfaces.

Meijun Zhu, Ph.D.; Manoella Mendoza, MS
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