Summary of Awards to Date

Development of post-harvest practical methods to reduce contaminations of Escherichia Coli O157:H7 on fresh produce.

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Sep. 1, 2008 - Aug. 31, 2010

Award Number


Funding Agency

Center for Produce Safety

Amount Awarded



Vivian C.H. Wu, Ph.D.
University of Maine


Consumption of fresh fruits and vegetables has increased in recent years. With an increase in consumption has come an increased frequency of foodborne outbreaks associated with raw or minimally processed fruits and vegetables. Bacterial foodborne outbreaks have been associated with fresh fruit and vegetable products including a recent Escherichia coli O157:H7 outbreak associated with spinach. Therefore, research is needed to better understand not only the mechanisms through which pathogens can contaminate fresh fruits and vegetables, but also the procedures for eliminating pathogens once they are present, either on the surface or in internal tissues, and the analytical methods for pathogen detection. Disinfectants are effective in reducing the bacterial load but their efficacy depends on the types of fruits and vegetables, characteristics of their surface, the method and the procedures used for disinfection, and the type of pathogens. In this proposed study, we will focus on development of mitigation measures aimed at eliminating and preventing contamination of E. coli O157:H7 on blueberries and spinach using a novel, simple, inexpensive, instrument-free, gaseous chlorine dioxide approach and early determining pathogen colonization and the degree of reductions after disinfection by a novel reliable oligonucletide-gold nanoparticle assay. While the definitive goal of this proposal is to reduce colonization by pathogens or cross contamination during post-harvest processing of fresh produce, the project will also yield significant results that meet a USDA/CSREES objective by reducing the number of foodborne illness in the U.S. and providing for the safe and economic regulation of food safety issues.