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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Environmental Microbial & Food Safety Laboratory » Research » Publications at this Location » Publication #370964
Research Project: Characterization and Mitigation of Bacterial Pathogens in the Fresh Produce Production and Processing Continuum

Location: Environmental Microbial & Food Safety Laboratory

Title: Effect of cultivars and irrigation waters on persistence of indicator bacteria on lettuce grown in high tunnel

Author
item YIN, HSI-BAI - Orise Fellow
item CHEN, CHI-HUNG - University Of Maryland
item KIARANTH, SHARDDHA - University Of Maryland
item BYUN, SEYEUN - Gachon University
item MAYER, CHRISTINE - Wilson College
item HARRIGER, DANA - Wilson College
item Patel, Jitu
item PRADHAN, ABANI - University Of Maryland

Submitted to: Journal of Food Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/11/2020
Publication Date: 3/31/2020
Citation: Yin, H., Chen, C., Kiaranth, S., Byun, S., Mayer, C., Harriger, D., Patel, J.R., Pradhan, A. 2020. Effect of cultivars and irrigation waters on persistence of indicator bacteria on lettuce grown in high tunnel. Journal of Food Safety. https://doi.org/10.1111/jfs.12795.
DOI: https://doi.org/10.1111/jfs.12795

Interpretive Summary: Water scarcity for irrigation has become a global issue, especially with accelerated population growth, increasing food demands, and adverse climatic conditions. The effect of non-traditional irrigation waters on microbiological safety of fresh produce was evaluated to determine its suitability during water shortage. Three cultivars of lettuce: Annapolis, Celinet, and Coastline grown in high tunnels were spray-irrigated with Primary-treated wastewater (PTWW), secondary-treated wastewater (STWW), or roof-collected rainwater (RCR) during the last two weeks prior to harvest. Significantly higher populations of E. .coli were recovered from lettuce when irrigated with the PTWW water The bacterial die-off rate on lettuce leaf was influenced by the cultivar of lettuce; E. coli populations were reduced the most on Annapolis lettuce 2 days after irrigation. The STWW and RCR irrigation did not significantly increase populations of indicator bacteria on lettuce plants. Small growers in Mid-Atlantic region could benefit from the study to utilize STWW and RCR waters containing low populations of indicator bacteria for lettuce irrigation without adversely affecting its microbial quality.

Technical Abstract: Effect of irrigation with groundwater (GW), primary-treated wastewater (PTWW), secondary-treated wastewater (STWW), and roof-collected rainwater (RCR) on microbial quality of lettuce cultivars “Annapolis”, “Celinet”, and “Coastline” grown in high tunnel was investigated. Lettuce plants were spray-irrigated with irrigation waters once a week for two weeks and analyzed for indicator and pathogenic bacteria. PTWW irrigation resulted in the highest E. coli recovery on the lettuce plants (4.7 log MPN/g) as compared to irrigation with other three waters on day 0. Lettuce cultivars affected the bacterial die-off rate, where E. coli populations reduced the most by 1. 5 log MPN/g on “Annapolis” lettuce analyzed 2 days after post irrigation. STWW and RCR irrigation did not significantly influence indicator bacteria on lettuce as compared to GW irrigation. The STWW and RCR containing low populations of indicator bacteria may be suitable for lettuce irrigation in Mid-Atlantic area without affecting its microbial quality.