Longitudinal Assessment of the Dynamics of Escherichia coli, Total Coliforms, Enterococcus spp., and Aeromonas spp. in Alternative Irrigation Water Sources: a CONSERVE Study

Sultana Solaiman, Sarah M. Allard, Mary Theresa Callahan, Chengsheng Jiang, Eric Handy, Cheryl East, Joseph Haymaker, Anthony Bui, Hillary Craddock, Rianna Murray, Prachi Kulkarni, Brienna Anderson-Coughlin, Shani Craighead, Samantha Gartley, Adam Vanore, Rico Duncan, Derek Foust, Maryam Taabodi, Amir Sapkota, Eric MayFawzy Hashem, Salina Parveen, Kalmia Kniel, Manan Sharma, Amy R. Sapkota, Shirley A. Micallef

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

As climate change continues to stress freshwater resources, we have a pressing need to identify alternative (nontraditional) sources of microbially safe water for irrigation of fresh produce. This study is part of the center CONSERVE, which aims to facilitate the adoption of adequate agricultural water sources. A 26-month longitudinal study was conducted at 11 sites to assess the prevalence of bacteria indicating water quality, fecal contamination, and crop contamination risk (Escherichia coli, total coliforms [TC], Enterococcus, and Aeromonas). Sites included nontidal fresh-water rivers/creeks (NF), a tidal brackish river (TB), irrigation ponds (PW), and reclaimed water sites (RW). Water samples were filtered for bacterial quantification. E. coli, TC, enterococci (~86%, 98%, and 90% positive, respectively; n = 333), and Aeromonas (~98% positive; n = 133) were widespread in water samples tested. Highest E. coli counts were in rivers, TC counts in TB, and enterococci in rivers and ponds (P< 0.001 in all cases) compared to other water types. Aeromonas counts were consistent across sites. Seasonal dynamics were detected in NF and PW samples only. E. coli counts were higher in the vegetable crop-growing (May-October) than nongrowing (November-April) season in all water types (P < 0.05). Only one RW and both PW sites met the U.S. Food Safety Modernization Act water standards. However, implementation of recommended mitigation measures of allowing time for microbial die-off between irrigation and harvest would bring all other sites into compliance within 2 days. This study provides comprehensive microbial data on alternative irrigation water and serves as an important resource for food safety planning and policy setting.

Original languageEnglish
Article numbere00342-20
JournalApplied and Environmental Microbiology
Volume86
Issue number20
DOIs
StatePublished - 1 Jan 2020
Externally publishedYes

Keywords

  • Aeromonas
  • Food Safety Modernization Act
  • fecal indicators
  • food safety
  • irrigation water
  • irrigation water physicochemical parameters

ASJC Scopus subject areas

  • Biotechnology
  • Food Science
  • Applied Microbiology and Biotechnology
  • Ecology

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