Researchers from several institutes investigating the prevalence and concentration of Salmonella and Campylobacter in the processing environment of small-scale pastured broiler farms found some evidence of environmental contamination with these foodborne pathogens.

Prevalence of both bacteria ranged between 48 and 64 per cent of the samples of soil, poultry compost and wastewater tested.

A growing niche in the locally grown food movement is the small-scale production of broiler chickens using the pasture-raised poultry production model, according to Lisa M. Trimble of the University of Georgia and co-authors in a paper published in Poultry Science. They explain that limited research exists that focuses on Salmonella and Campylobacter contamination in the environment associated with on-farm processing of pasture-raised broilers.

The objective of this study - with the University of Arkansas, Oklahoma State University and USDA-ARS Russell Research Center - was to establish data relative to Salmonella and Campylobacter prevalence and concentration in soil and mortality compost resulting from prior processing waste disposal in the small-scale, on-farm broiler processing environment.

Salmonella and Campylobacter concentrations were determined in soil (n=42), compost (n=39) and processing wastewater (n=46) samples from four small broiler farms using a three-tube most probable number (MPN) method for Salmonella and direct plating method for Campylobacter.

Salmonella prevalence and concentration (mean log₁₀ MPN per sample weight or volume) in:

• soil: 60 per cent; 0.97; 95 per cent CI: 0.66 to 1.27
• compost: 64 per cent; 0.95; 95 per cent CI: 0.66 to 1.24, and
• wastewater: 48 per cent; 1.29; 95 per cent CI: 0.87 to 1.71.

These were not significantly different (P>0.05) from one another.

Campylobacter prevalence was not significantly different by sample type - 64.3, 64.3 and 45.7 per cent in soil, compost and processing wastewater, respectively. However, the Campylobacter concentration (mean log₁₀ colony-forming units, cfu) was significantly lower (P<0.05) in wastewater than soil or compost, with the results as follows:

• wastewater: 2.19; 95 per cent CI: 0.36 to 3.03
• soil: 3.08; 95 per cent CI: 2.23 to 3.94, and
• compost: 3.83; 95 per cent CI: 2.71 to 4.95.

These data provide insight into small-scale poultry production waste disposal practices and provides a record of data that may serve as a guide for future improvement of these practices, according to Trimble and co-authors.

They suggest that further research is needed regarding the small-scale broiler production environment in relation to improving disposal of processing waste for optimum control of human pathogens.

Reference

Trimble L.M., W.Q. Alali, K.E. Gibson, S.C. Ricke, P. Crandall, D. Jaroni, M. Berrang and M.Y. Habteselassie. 2013. Prevalence and concentration of Salmonella and Campylobacter in the processing environment of small-scale pastured broiler farms. Poult. Sci. 92(11):3060-3066. doi: 10.3382/ps.2013-03114