Summary of Awards to Date

Filth fly transmission of human enteric pathogens to pre-harvest fresh produce.

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Sep. 1, 2009 - Aug. 31, 2013

Award Number


Funding Agency

Center for Produce Safety

Amount Awarded



Astri Wayadande, Ph.D
Oklahoma State University


Gerry, A., Talley, J., Millar, J., Fletcher, J., DeSilva, U., and Michailides, T.


Filth flies are insects such as houseflies, blowflies, and/or flesh flies that develop in fecal material, decomposing animals or rotting plants. In addition to necrotic tissue, these flies must feed upon bacteria in order to complete their life cycle. As a result, filth flies are well-known vectors of human pathogens in situations where they can come in contact with prepared foods or hospital surfaces. However, the role of filth flies as carriers of pathogens to food plants is not well understood. In cropping systems where fly breeding areas such as animal production facilities are in close proximity to fresh produce production areas it is important to understand when and under which conditions flies will move to, and make contact with, plants intended for human consumption. The work outlined in this project will determine if flies are efficient vectors of two foodborne disease pathogens, Salmonella spp. and E. coli O157:H7 to pre-harvest leafy greens. Our work has several goals: We will determine 1. if some species of flies are better enteric bacteria vectors than others 2. the optimal dispersal distance of flies carrying transmissible pathogenic bacteria 3. if bacterial profiling can be used to trace the origin of flies 4. whether bacteria regurgitated by flies onto plant surfaces can move into the plant (internalize) and 5. identify odors emanating from plants infested with aphids or whiteflies that are attractive to flies. This information will be used to develop and implement foodborne pathogen risk-reduction strategies in fresh produce cropping systems.