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The goal of the project is to reduce colonization by pathogens or cross contamination during post-harvest processing of fresh produce and 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. <P> Our proposed objectives are to: <OL> <LI> Develop a novel, simple, inexpensive, instrument-free gaseous ClO2 approach for disinfection of fresh produce <LI>Develop an efficient, sensitive, and applicable protocol to detect E. coli O157:H7 from fresh produce by using gold nanoparticle sandwich hybridization for early determining pathogen colonization and the degree of reductions after disinfection. </ol>We expect that gaseous ClO2 with low concentrations (either slow or fast release) is expected to effectively reduce the level of E. coli O157:H7 on spinach leaves or blueberries without damage the visual quality. We expect gold nanoparticle sandwich hybridization can be used as a simple and inexpensive method for detection of E. coli O157:H7.
NON-TECHNICAL SUMMARY: 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.
<P>APPROACH: In this proposed study, we will focus on the 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. The experiments will be repeated three times. Analysis of variance (ANOVA) will be performed on cell counts using the SAS General Linear Models procedure. Means of three replicates will be plotted in graphs, and significant differences determined at the 95% confidence limit. Differences among treatments will be evaluated by the Least Square Difference (LSD) test The fresh produce community can adopt the simple and inexpensive gaseous ClO2 disinfectant approach and DNA-AuNPs sandwich hybridization assay to integrate them at numerous points during fresh produce processing to eliminate pathogen contaminations and prevent recalls and economic loss associated with foodborne outbreaks.