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Author Notes:

Correspondence: Karen Levy, Department of Environmental Health, Emory University, 1518 Clifton Road NE, Atlanta, GA 30322, USA. karen.levy@emory.edu, Casey Harris, Bureau of Water Resources, St. Johns River Water Management District, P.O. Box 1429, Palatka, FL 32178, USA. csharris9@gmail.com.

We gratefully acknowledge the fruit and vegetable growers who allowed us to collect water samples from their farms.

Georgia Department of Public Health provided data on serovars in cases of salmonellosis for 2012–2013.

Camilla Borgato, Debbie Coker, Charles Gruver, Jill Johnson, Debbie Lee, and Katy Summers provided field and lab assistance, Berry Brosi provided statistical assistance, and Richard Lowrance, Mia Mattioli, and Catherine Pringle provided design and/or editorial assistance.

No conflict of interest declared.


Research Funding:

This work was supported by grant SCB11063 from the Center for Produce Safety, Davis, California.

The Center for Produce Safety had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Any mention of trade names or commercial products does not constitute endorsement or recommendation.


  • Science & Technology
  • Life Sciences & Biomedicine
  • Biotechnology & Applied Microbiology
  • Microbiology
  • agriculture
  • environmental
  • epidemiology
  • Salmonella
  • water

Impact of storm runoff on Salmonella and Escherichia coli prevalence in irrigation ponds of fresh produce farms in southern Georgia


Journal Title:

Journal of Applied Microbiology


Volume 124, Number 3


, Pages 910-921

Type of Work:

Article | Post-print: After Peer Review


Aims: To examine Salmonella and Escherichia coli in storm runoff and irrigation ponds used by fresh produce growers, and compare Salmonella serovars with those found in cases of human salmonellosis. Methods and Results: We collected water before and after rain events at two irrigation ponds on farms in southern Georgia, USA, and collected storm runoff/storm flow within the contributing watershed of each pond. Salmonella and E. coli concentrations were higher in ponds after rain events by an average of 0·46 (P < 0·01) and 0·61 (P < 0·05) log10 most probable number (MPN) per 100 ml respectively. Salmonella concentrations in storm runoff from fields and forests were not significantly higher than in ponds before rain events, but concentrations in storm flow from streams and ditches were higher by an average of 1·22 log10 MPN per 100 ml (P < 0·001). Eighteen Salmonella serovars were identified from 155 serotyped isolates, and eight serovars were shared between storm runoff/storm flow and ponds. Seven of the serovars, including five of the shared serovars, were present in cases of human illness in the study region in the same year. However, several serovars most commonly associated with human illness in the study region (e.g. Javiana, Enteritidis, and Montevideo) were not found in any water samples. Conclusions: Salmonella and E. coli concentrations in irrigation ponds were higher, on average, after rain events, but concentrations of Salmonella were low, and the ponds met FDA water quality standards based on E. coli. Some similarities and notable differences were found between Salmonella serovars in water samples and in cases of human illness. Significance and Impact of the Study: This study directly examined storm runoff/storm flow into irrigation ponds and quantified increases in Salmonella and E. coli following rain events, with potential implications for irrigation pond management as well as human health.

Copyright information:

© 2018 The Society for Applied Microbiology

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