Development of a Simple, Quantitative Kit to Test Vegetables and Fruits for Evidence of Fecal Contamination

NON-TECHNICAL SUMMARY: One of the most vulnerable sectors in the food industry includes "ready-to-eat" fruits and vegetables that may be consumed without peeling, pasteurization, or cooking. Increases in the year-round consumption of fresh fruits and vegetables that are out of season in the United States, coupled with the relaxation of international trade restrictions, have resulted in significant increases in the importation of produce from developing countries where oversight of irrigation, washing, and handling practices may not be as stringent as in the U.S. Because this produce is generally not cooked prior to consumption, foodborne outbreaks can result from microbiological contamination of crops irrigated using substandard water, reclaimed water or wastewater. Because it may never be possible to test ready-to-eat food products directly for all possible microbial contaminants, the development and commercialization of rapid, simple and economical indirect testing methods for assessing fecal contamination is highly desirable. This proposal addresses the need to develop a robust, rapid and economical method for the determination of fecal contamination of ready-to-eat produce.

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APPROACH: The phase II study continues the development of a simple and economical product, Easyphage, that can be used to assess ready-to-eat food products for evidence of fecal contamination. Development of Easyphage takes into account the lessons learned from previous efforts to validate fecal contamination indicators including coliphages. The research strategy considers challenges identified during the Phase I research efforts such as ambiguities in scoring viral plaques and limitations associated with extended assay turnaround times. The Phase II research study is divided into the following work assignments to achieve the project objectives: Validation of a simple, rapid and economical indicator system, Easyphage, that can be used by modestly equipped laboratories to assess ready-to-eat food products for evidence of fecal contamination. Development and validation of an efficient extraction media for the recovery of indicator microorganisms (coliphages) from ready-to-eat produce. Development of a simplified enumerative assay to quantify male-specific coliphages in the extraction buffer/eluate. Validation of a agar substitute that does not require steam sterilization and that eliminates the need for precise temperature monitoring agar during assay. Validation of a method to enhance visualization of viral plaques using a chromogenic substrate. Use of the Easyphage assay to perform a multi-state field study of ready-to-eat food purchased in US retail food stores.

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PROGRESS: 2006/09 TO 2007/09<BR>
SMI has demonstrated EasyPhage kits during May 2007 at the General Meeting of American Society for Microbiology and also present a poster. Many microbiologists from education and research universities as well as other research laboratories visited the SMI booth and requested a sample kit. SMI has sent out more than 50 kits. Largely as a result of significant interest at the 2007 ASM General Meeting, researchers at the following companies and universities have received one or more EasyPhage kit: Ivy Tech College, Tufts University, Codexis (CA), Metropolitan Water Reclamation District, University of Washington -Seattle, Texas A & M, North Carolina State Univ -Food Science Dept., Utica College, Los Angeles County Sanitation Districts, Dalynn Biologicals, Texas A & M University, Auburn University, Ohio Wesleyan University, Virginia Tech, University of Guelph, University of South Florida, American Water Works SVC Co., Inc, Computer Science Corp, Food & Drug Administration, BCS Laboratories, University of Washington, University of Wisconsin/State Lab of Hygiene, USGS, Southeast Missouri State University, US Geological Survey, 3M Center Canadian Research Institute for Food Safety, Cook College, Rutgers University, North Shore Community College, Mary Mount University, Public Health Agency of Canada, Natl. Center for Toxicological Research, University of Mississippi State, Kirkegard & Perry Laboratories. Inc, Sul Ross State University We are actively following up to receive customer feedback and determine their interest in purchasing additional EsayPhage products. About 30 EasyPhage kits have been sold for educational and research purposes. It is worth noting that a pharmaceutical company has recently purchased 7 kits to detect somatic coliphages from genetically modified E. coli fermentation.
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IMPACT: 2006/09 TO 2007/09 <BR>
The research continues to closely follow the Phase II project's work plan. Currently, samples of the EasyPhage educational kit have been offered to science teachers and college professors. A soft launch of the product has taken place and a dozen 10 test kits have been purchased. The EasyPhage 10 test kit can be purchased at www.scientificmethods.com and a permanent website with an automated shopping cart is nearly complete at www.micrologymethods.com. A second product configuration, having 100 ml of medium rather than 10 ml, is under development for food testing labs and for water testing labs. This new format will be allow a more economical approach to testing food for the presence of these indicator viruses that are documented to be associated with the presence of fecal contamination and pathogenic viruses. These viruses are also more resistant to desiccation than E. coli bacteria and should indicate fecal contamination even if the E.coli has perished en route to the consumer. After SMI conducts next summer's national food basket survey, meaningful range values will be generated that will permit users to compare their coliphage results to historical food samples results. This tool will allow food distributors and processors to better protect their customers from food that may be contaminated with pathogenic viruses and fecal matter.