Evaluation of subsurface irrigation on microorganism contamination of romaine lettuce

Rocio G. Reyes Esteves, Charles P. Gerba, Donald C. Slack

Research output: Contribution to journalConference articlepeer-review

3 Scopus citations


The use of contaminated water to irrigate crops by surface, sprinkler, or conventional drip irrigation represents a significant public health concern due to the presence of multiple microbial pathogens associated with gastrointestinal disease. In this study, Escherichia coli and MS2 bacteriophage were used as microbial surrogates to evaluate the contamination of romaine lettuce (Lactuca sativa L. var. longifolia) using bottom watering pots simulating a subsurface drip irrigation (SDI) system in a greenhouse. The primary goal was to determine whether the exposure of lettuce plants to E. coli and MS2 would result in detectable levels of these microorganisms associated with the edible portions of plants. Plants were grown in bottom watering pots and were irrigated the last twelve days before harvesting with contaminated water containing E. coli and MS2 phage at 109 CFU/ml and 1011 PFU/ml, respectively. Harvested plants were processed to determine if E. coli or MS2 was associated with the plant surfaces or within the plant tissues. None of the samples was positive for either E. coli or MS2 bacteriophage, suggesting that subsurface irrigation systems effectively reduce the risk of produce-contamination with bacterial and viral pathogens.

Original languageEnglish (US)
Article number04009
JournalE3S Web of Conferences
StatePublished - Sep 8 2020
Event13th Thai Society of Agricultural Engineering International Conference, TSAE 2020 - Nakhon Ratchasima, Thailand
Duration: Jul 30 2020Jul 31 2020

ASJC Scopus subject areas

  • General Environmental Science
  • General Energy
  • General Earth and Planetary Sciences


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