Characterization of the lettuce microbial community by metagenomic sequencing and optical light scattering

The overall goal of this work is to use next generation sequencing coupled with BEAM, to identify the bacteria and fungi that are present on romaine lettuce. Changes in the microbial communities will be characterized following the addition of bacterial pathogens. This will help establish possible indicator organisms that can be used to detect contamination if present, as well as establish a library for BEAM that can be used by the leafy green industry to rapidly sample products to determine the spoilage and/or pathogenic organisms present.Objective 1: Develop a BEAM library of bacterial and fungal genera associated with romaine lettuce and validate BEAM as a tool for making taxonomic assignments at the genus level.Objective 2: Determine the effect of lettuce bacterial community composition and spatial distribution on the ability of human pathogens to establish themselves in the community and survive treatment with chemical sanitizers. This objective will also identify organisms that are possible indicators for the presence of human pathogens.