Summary of Awards to Date

When the E. coli hits the fan! Evaluating the risks of dust-associated produce cross-contamination

Date

Jan. 1, 2021 - Dec. 31, 2022

Funding Agency

Center for Produce Safety

Amount Awarded

$193,378.00

Investigator

Kelly R. Bright, Ph.D
University of Arizona

Co-Investigator(s)

Walter Q. Betancourt, Ph.D., Charles P. Gerba, Ph.D.

Summary

Dust represents an understudied vehicle for microbial dispersal and produce contamination by pathogens. Dust deposition onto crops during cultivation is inevitable as plant surfaces serve as a major aerosol sink and dust can serve as a vehicle for bacteria. Wind-driven distribution of dust in agricultural environments can also impact food safety when the sources of dust include particles from natural and human-related reservoirs of pathogens. While the populations of enteric pathogens in water is frequently determined and the microbiological quality of soils are monitored, the evaluation of dust and soil-borne particulates is rarely conducted. This study proposes the following: 1). To evaluate the role of dust in transferring foodborne pathogens to produce surfaces grown in eastern and western regions of the US, 2). To determine the role of humidity in the deposition of dust on produce and the survival of pathogens in dust, and 3). To test dust particulates from animal operations in both regions for the presence of biomarkers indicative of fecal contamination and potentially the presence of pathogens. This study will enhance our understanding of pathogen transport from feces into and through produce fields and will quantify the risk associated with contamination from dust under varying environmental/atmospheric conditions.

Technical Abstract

Dust, broadly defined as fine particulate matter resulting from wind erosion on land surfaces and suspended in the air, is an inseparable component of the atmosphere. Dust represents an understudied vehicle for microbial dispersal in agricultural environments and produce contamination by microorganisms pathogenic to humans. Dust not only affects biological processes in plants, such as stomatal gas exchange, but also the plant surface microbiome. Dust deposition onto crops during field cultivation is inevitable as plant surfaces serve as a major aerosol sink. Studies have indicated that dust can serve as a vehicle for bacteria. Wind-driven distribution of dust in agricultural environments could also impact food safety when the sources of dust include particles from natural (soil, decaying vegetation, feral/wild animal droppings) and human-related (manure-amended soils, silage, municipal sewage-based biosolids, composting, and animal production facilities) reservoirs of human pathogens. While the populations of enteric pathogens in water is frequently determined through periodic testing as recommended by the Food Safety Modernization Act (FSMA) and the microbiological quality of soils are monitored, the evaluation of dust and soil borne particulates is rarely carried out. This study proposes the following: 1). To evaluate the role of dust in transferring foodborne pathogens to the surfaces of produce commodities specific to the eastern and western agricultural regions of the United States, 2). To determine the role of humidity in the deposition of dust on produce and the survival of foodborne pathogens in dust particulates, and 3). To test dust particulates from animal operations in Georgia and Arizona for the presence of biomarkers indicative of fecal contamination and the presence of enteric pathogens. This project will enhance our understanding of pathogen transport from feces into and through produce fields and will quantify the risk associated with contamination from dust under varying environmental and atmospheric conditions.