P3-218 Generic E. coli Levels in Surface and Non-traditional Irrigation Water in the Mid-Atlantic in Relation to FSMA Water Quality Standards: A CONSERVE Study

Wednesday, July 12, 2017
Exhibit Hall (Tampa Convention Center)
Sarah Allard , Maryland Institute for Applied Environmental Health, University of Maryland, School of Public Health , College Park , MD
Sultana Solaiman , University of Maryland , College Park , MD
Mary Theresa Callahan , University of Maryland , College Park , MD
Eric Handy , U.S. Department of Agriculture–ARS , Beltsville , MD
Cheryl East , U.S. Department of Agriculture–ARS , Beltsville , MD
Hillary Craddock Kelbick , Maryland Institute for Applied Environmental Health, University of Maryland, School of Public Health , College Park , MD
Rianna Murray , Maryland Institute for Applied Environmental Health, University of Maryland, School of Public Health , College Park , MD
Anthony Bui , Maryland Institute for Applied Environmental Health, University of Maryland, School of Public Health , College Park , MD
Joseph Haymaker , University of Maryland Eastern Shore , Princess Anne , MD
Derek Foust , University of Maryland Eastern Shore , Princess Anne , MD
Samantha Gartley , University of Delaware , Newark , DE
Adam Vanore , University of Delaware , Newark , DE
Salina Parveen , University of Maryland Eastern Shore , Princess Anne , MD
Fawzy Hashem , University of Maryland Eastern Shore , Princess Anne , MD
Maryam Taabodi , University of Maryland Eastern Shore , Princess Anne , MD
Eric May , University of Maryland Eastern Shore , Princess Anne , MD
Kalmia Kniel , University of Delaware , Newark , DE
Manan Sharma , U.S. Department of Agriculture–ARS , Beltsville , MD
Shirley Micallef , University of Maryland , College Park , MD
Amy Sapkota , Maryland Institute for Applied Environmental Health, University of Maryland, School of Public Health , College Park , MD
Introduction: The use of surface (pond and river) and nontraditional (reclaimed wastewater, produce wash water) irrigation water (SNIW) could reduce demand on groundwater resources. However, it is essential to understand how these irrigation sources may influence the microbiological safety of fresh produce, and how they comply with FSMA irrigation water quality standards (Geometric Mean (GM) of 126 CFU/100ml and Statistical Threshold Value (STV) of 410 CFU/100ml of Escherichia coli).

Purpose: To evaluate SNIW sources for the presence of generic E. coli and compare the GM and STV from these sites to FSMA standards.

Methods: Surface and nontraditional irrigation water (100ml) from 12 sites (n=51) in the Mid-Atlantic was collected and filtered for enumeration of E. coli by standard membrane filtration (EPA Method 1604). Water from 8 surface water sites, 3 reclaimed wastewater sites, and a produce processing facility were evaluated on up to 6 different dates (Sept–Dec 2016). E. coli was quantified on MI agar, and GM and STV were calculated from all available data.

Results: E. coli levels below 126 CFU/100ml were found in 47% of water samples analyzed. Of the 12 sites analyzed, 7 had a GM above the 126 CFU/100ml FSMA threshold. The FSMA STV of 410 CFU E. coli /100ml was exceeded in 10/12 sites examined. Of all surface and nontraditional water sources tested, only 2 sites, both reclaimed wastewater, had E. coli levels below GM and STV thresholds. Overall, samples collected from river water and vegetable processing sites contained higher levels of E. coli, while reclaimed wastewater (chlorinated before sampling) and pond water contained lower levels of E. coli.

Significance: Many surface and nontraditional irrigation water sources in the Mid-Atlantic analyzed from Sept–Dec 2016 would require mitigation before use as irrigation water for fresh produce crops to comply with FSMA standards.