Center for Produce SafetyInvestigator
Linda J. Harris, Ph.D.
University of California, Davis
Sudarshana, M., Li, H., and Suslow, T.Summary
This project investigates the factors that influence the ability of E. coli O157:H7 to multiply on lettuce and leafy greens in the presence of normal background flora. Comparative growth kinetics of E. coli O157:H7 on bagged romaine lettuce and spinach in simulated standard and sub-optimal post-harvest temperatures, and the various factors that influence growth rates, will be evaluated. It is hypothesized that sub-optimal temperature management may play a significant role in the growth of E. coli O157:H7 on produce during harvesting, processing, distribution, and pre-consumption handling. How well E. coli O157:H7 is able to grow under these conditions may depend also on conditions of the plant (variety, age, growing conditions, day length, method of harvest, moisture at harvest, and soluble nutrients), the bacteria (pre-inoculation stress and growth conditions) and the post-inoculation environment. Results of this project will support the development of optimal pre-harvest, harvest, and post-harvest preventive programs and improved predictive models for host-pathogen and environment-pathogen interactions.