P1-161 An Assessment of the Potential for Movement of Microorganisms from a Poultry Operation to an Adjacent Almond Orchard

Sunday, July 26, 2015
Exhibit Hall (Oregon Convention Center)
Chris Theofel, University of California, Davis, Davis, CA
Thomas Williams, University of California, Davis, Davis, CA
Eduardo Gutierrez, North Carolina State University, Raleigh, NC
Gordon Davidson, University of California, Davis, Davis, CA
Peiman Aminabadi, University of California, Davis, Davis, CA
Michele T. Jay-Russell, University of California, Davis, Davis, CA
Linda J. Harris, University of California, Davis, CA
Introduction: Salmonella is found in raw unprocessed almonds at a prevalence of about 1%. Although contamination likely occurs in the orchard, sources of the Salmonella are not well understood.   

Purpose: To evaluate the potential for transfer of microorganisms from a poultry operation to an adjacent almond orchard. 

Methods: Orchard surface (drag swab), air (microbiological air sampling device), soil, and dust (almond leaf surface) samples were collected in an orchard adjacent (< 35 m) to a commercial poultry operation (“poultry orchard”) and two control orchards (surrounded by other almond orchards) over a 3-year period. Dry solids rinsed from leaf surfaces, aerobic plate count, presence of Salmonella and Escherichia coli, and bacterial community analysis through 16s rRNA next-generation sequencing were determined. 

Results: Salmonella was isolated from one of the 804 samples evaluated. E. coli was isolated from 64 of 186 (34%) and 1 of 207 (0.48%) air samples in the poultry and control orchards, respectively. On average, the amount of dry solids collected from almond trees closest to the poultry operation was more than two-fold greater than from trees 120 m into the orchard or in the control orchards. The microbiota identified in leaf dust samples collected from the poultry orchard was more diverse than those from the control orchards. Members of the Staphylococcaceae family – often associated with poultry – were, on average, more abundant (12%) in the phyllosphere of trees closest to the poultry operation than in trees 120 m into the orchard (2.1%) or in control orchards (0.39%).  

Significance: Poultry-associated microorganisms from animal operations may transfer a short distance into adjacent orchards; the food safety implication of this movement is unknown.