Research questions role of poultry processing plants in stormwater contamination

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USPOULTRY and the USPOULTRY Foundation announce the completion of a funded research project at the University of Georgia, Athens, Ga., in which researchers question the role of poultry processing plants in stormwater bacterial contamination. The research is part of the Association’s comprehensive research program encompassing all phases of poultry and egg production and processing. A brief summary of the completed project is shown below.

Project #F064: Impact and Mitigation of Stormwater Runoff from Poultry Processing Plants
Dr. Brian Kiepper and colleagues at the University of Georgia and the Georgia Tech Research Institute recently completed a research project where they determined the typical level of bacterial contamination found in surface water upstream from the site of a poultry processing plant. They found significant levels of coliform bacteria in streams prior to any stormwater runoff from poultry processing plants. These results indicate that the contribution of poultry processing plants to stream bacterial load may be overestimated.

Impact and mitigation of stormwater runoff from poultry processing plants
The U.S. poultry industry understands that the handling of live birds at large scale processing facilities can lead to the potential for contaminated stormwater runoff from the areas where live haul trailers are held and unloaded. However, the focused scrutiny given to poultry processing facilities overemphasizes the industry’s true impact on the environment. Most U.S. poultry processing plants operate under state-issued National Pollutant Discharge Elimination System general stormwater permits, with specific provisions for facilities that handle live animals. These provisions include the detection of surrogate “indicator” bacterial organisms in surface water in the attempt to infer the potential impact an individual processing facility might have in introducing pathogenic bacteria into the environment. Research in related stormwater areas, such as urban watersheds, has continually shown weak correlations between the detection of indicator organisms and the presence of pathogenic bacteria. Nevertheless, the use of indicator bacteria is the accepted method of evaluating the contamination of surface waters. The detection of indicator organisms and practices to reduce their numbers in stormwater runoff will continue to be the focus for poultry processing plants in the foreseeable future.

A primary objective of this study was to identify and quantify the level of background indicator organisms already existing (under dry weather conditions) in watersheds impacted by poultry processing facilities in urban heavy industrial, suburban light commercial, and rural settings. In the table below can be seen the results for the poultry processing plants tested in this study. The data represent the cumulative upstream results for five poultry processing facility locations for a one year period. Mean most probable number (MPN/100mL) of bacterial indicator organisms per 100mL of surface water upstream of five poultry processing facilities under dry (no storm water discharge) conditions over a 12 month period (July 2015 – June 2016).

Indicator Organism
Urban Heavy Industrial (2 sites)
Suburban Light Commercial (2 sites)
Rural (1 site)

These results clearly indicate that there is a significant presence of traditionally monitored indicator organisms (total coliforms, fecal coliforms, generic E. coli) prior to any impact from poultry processing facility stormwater runoff. While the presence of indicator organisms is significantly less in a rural setting versus an urban industrial or suburban commercial setting, even the results from the rural setting show that a significant presence of indicator organisms exists under dry conditions and upstream of any poultry processing activities. The use of fecal indicator bacteria is the accepted method for monitoring fecal contamination of watersheds but this method takes multiple days to complete and is not species specific. The method provides no indication of the potential source of the fecal indicator bacteria found in a stream. As part of this grant, several molecular microbial source tracking methods were investigated. Once verified, the chicken feces-specific PCR assays tested during this project may provide a faster and species-specific method for identifying chicken fecal contamination and may be an important tool for poultry processors.