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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Produce Safety and Microbiology Research » Research » Research Project #444641

Research Project: Functional Modulation of Escherichia coli O157:H7 by the Lettuce Phyllosphere Microbiome

Location: Produce Safety and Microbiology Research

Project Number: 2030-42000-052-013-R
Project Type: Reimbursable Cooperative Agreement

Start Date: Oct 1, 2022
End Date: Apr 30, 2026

1) Investigate foodborne pathogen-microbiome associations at the single-cell resolution in the lettuce phyllosphere; 2) identify members of the natural microbiota that inhibit E. coli O157:H7 at the scale of single cells on pre- and post harvest lettuce leaves; and 3) determine the effect of the production of surfactant and siderophores by phyllospere microbiota on E. coli O157:H7 cell viability and dispersal during washing and processing.

The first part of this project will use a microbiome approach to characterize the various members of lettuce leaves that reside closely to EcO157 in the phyllosphere at the resolution of single cells. To investigate the associations of epiphytic bacterial species with E. coli O157:H7 in situ at the microscale, a highly multiplexed spatial mapping of microbial communities based on HiPR-FISH will be used. This will provide a map of spatial organization of the human pathogen cells and resident species. The use of viability stains will further elucidate the effect of neighboring species on the pathogen at high resolution on leaf surfaces. Finally, known epiphytic strains that produce surfactants, siderophores, and inhibitory substances will be investigated for their effect on the dispersal and survival of E. coli O157:H7 on lettuce during processing and in packaging under cold storage and temperature abuse.