Summary of Awards to Date

Food safety risks at the fresh produce-animal interface: identifying pathogen sources and their movement on diversified farms


Jan. 1, 2014 - Dec. 31, 2015

Award Number


Amount Awarded



Siddhartha Thakur, Ph.D.
North Carolina State University


Eduardo Gutierrez-Rodriguez, Ph.D., Chris Gunter, Ph.D., Benjamin Chapman, Ph.D., Irene Hanning, Ph.D.


A potential source of fresh produce contamination is the direct application or indirect transfer of animal manure into the produce farm environment. One clear knowledge gap that exists is in ascertaining the specific metrics and consequences of proximity at the interface of agricultural production involving food animals and fresh produce. Without this information, it is difficult to prescribe practical risk-reduction practices and expect producers to heed measures. This is especially true in case of “Diversified” farms where the integration of growing animal and fresh produce in close proximity predisposes the fresh produce to contamination by animal shed pathogens. To address this, we propose to 1) Identify sources of Salmonella, STEC O157:H7 and non- O157:H7 STEC on diversified farms and determine the impact of buffer distance on their movement at the animal: fresh produce interface; and 2) Validate the outcome of first objective by conducting a controlled study to determine source and the movement of indicators and pathogens at the animal: produce interface on the Piedmont Agriculture Research Station reflective of a diversified enterprise. We strongly believe that the study will result in identifying risk gaps and help the fresh produce industry to strategize control measures to prevent fresh produce contamination.

Technical Abstract

The emergence and growth of the “Eat Local” movement has contributed directly to the growth of diversified farms which promotes rearing livestock and growing fresh produce within the same agricultural system. The interface of food animals and fresh produce in agricultural production is an area in need of information that could potentially reduce the risk of pathogen transmission and freshproduce contamination. The primary goal of this project will be to determine the potential transmission of Salmonella, Shiga Toxin-Producing (STEC) Escherichia coli O157:H7 and non-O157:H7 STEC from animal operations that are in close proximity to vegetable production systems on an experimental research station and commercial diversified farming operations. To attain this goal, we propose to pilot a controlled study on an agriculture research station to determine the impact of multiple farm variablesincluding buffer zone distances, temporal factors, air and insect on transmission of the above pathogens between animals and fresh produce operations. Information collected from controlled studies will be complemented with data generated on commercial diversified farms which will help identify the key sources, track movement of pathogens, narrow the ‘how-to’ information gap, and help the produce industry to strategize control measures to improve food safety.