Effect of Ultraviolet Water Treatment on Survival and Growth of Escherichia coli in Recirculating Hydroponic Systems

Hydroponic nutrient solution can serve as a distribution mechanism for human pathogens to spread throughout an indoor farm since many hydroponic farms do not include water treatment during the crop growth period. Contamination can be introduced to recirculating nutrient solution through various rout...

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Main Authors: Markanna Moore, Teng Yang, Majid Jaberi Douraki, Cary Rivard, Eleni Pliakoni, Londa Nwadike, Manreet Bhullar
Format: Article
Language:English
Published: Elsevier 2025-08-01
Series:Journal of Food Protection
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Online Access:http://www.sciencedirect.com/science/article/pii/S0362028X25001279
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author Markanna Moore
Teng Yang
Majid Jaberi Douraki
Cary Rivard
Eleni Pliakoni
Londa Nwadike
Manreet Bhullar
author_facet Markanna Moore
Teng Yang
Majid Jaberi Douraki
Cary Rivard
Eleni Pliakoni
Londa Nwadike
Manreet Bhullar
author_sort Markanna Moore
collection DOAJ
description Hydroponic nutrient solution can serve as a distribution mechanism for human pathogens to spread throughout an indoor farm since many hydroponic farms do not include water treatment during the crop growth period. Contamination can be introduced to recirculating nutrient solution through various routes, including growing media and worker contact. In leafy green production, it is common for nutrient solution to inadvertently contact produce during harvest or packaging. Therefore, it is critical that such water be free of human pathogens. Ultraviolet (UV) treatment of water could reduce contamination in nutrient solution without disrupting production or introducing new chemical inputs to the nutrient solution.This study investigated the survival of generic Escherichia coli (E. coli) in hydroponic systems and assessed the efficacy of a 254 nm UV-C light treatment for E. coli reduction. Romaine lettuce was grown in hydroponic systems for six weeks. E. coli was inoculated into hydroponic nutrient solution at 6.02 average log CFU/mL UV-C treatments of water were performed biweekly. Hydroponic controls grew plants but received no UV-C treatment, and nonhydroponic controls neither grew plants nor received treatment. The efficacy of the treatment was assessed in terms of bacterial reduction in log CFU/mL.The UV-C treatments resulted in significant (P < 0.001) reductions of 1.4–1.5 log10 CFU/mL of E. coli in the nutrient solution. However, the E. coli population declined naturally over the weeks following the inoculation, independent of the UV-C treatment. Survival of E. coli beyond one week is limited in the nutrient solution. Still, UV-C treatment has the potential to be used as a preventative safeguard for the microbial safety of the hydroponic production system by reducing contamination within the nutrient solution during crop growth. This can help maintain the safety of hydroponically grown fresh produce and reduce the likelihood of future outbreaks.
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spelling doaj-art-758b20f49a2b40d49d398e6ab1a4fb6e2025-08-23T04:47:29ZengElsevierJournal of Food Protection0362-028X2025-08-0188910057510.1016/j.jfp.2025.100575Effect of Ultraviolet Water Treatment on Survival and Growth of Escherichia coli in Recirculating Hydroponic SystemsMarkanna Moore0Teng Yang1Majid Jaberi Douraki2Cary Rivard3Eleni Pliakoni4Londa Nwadike5Manreet Bhullar6Department of Horticulture and Natural Resources, Kansas State University, Olathe, KS 66061, USADepartment of Agronomy, Horticulture, and Plant Science, South Dakota State University, Brookings, SD 57006, USA1Data Consortium, Kansas State University, Olathe, KS 66061, USA; Department of Mathematics, Kansas State University, Manhattan, KS 66506, USAEastern Kansas Research and Extension Centers, Kansas State University, Manhattan, KS 66506, USADepartment of Horticulture and Natural Resources, Kansas State University, Olathe, KS 66061, USADepartment of Dairy and Food Science, South Dakota State University, Brookings, SD 57006, USADepartment of Horticulture and Natural Resources, Kansas State University, Olathe, KS 66061, USA; Food Science Institute, Kansas State University, Manhattan, KS 66506, USA; K-State Research and Extension, Kansas State University, Manhattan, KS 66506, USA; Corresponding author at: 22201 W. Innovation Drive, Olathe, KS 66061, USA.Hydroponic nutrient solution can serve as a distribution mechanism for human pathogens to spread throughout an indoor farm since many hydroponic farms do not include water treatment during the crop growth period. Contamination can be introduced to recirculating nutrient solution through various routes, including growing media and worker contact. In leafy green production, it is common for nutrient solution to inadvertently contact produce during harvest or packaging. Therefore, it is critical that such water be free of human pathogens. Ultraviolet (UV) treatment of water could reduce contamination in nutrient solution without disrupting production or introducing new chemical inputs to the nutrient solution.This study investigated the survival of generic Escherichia coli (E. coli) in hydroponic systems and assessed the efficacy of a 254 nm UV-C light treatment for E. coli reduction. Romaine lettuce was grown in hydroponic systems for six weeks. E. coli was inoculated into hydroponic nutrient solution at 6.02 average log CFU/mL UV-C treatments of water were performed biweekly. Hydroponic controls grew plants but received no UV-C treatment, and nonhydroponic controls neither grew plants nor received treatment. The efficacy of the treatment was assessed in terms of bacterial reduction in log CFU/mL.The UV-C treatments resulted in significant (P < 0.001) reductions of 1.4–1.5 log10 CFU/mL of E. coli in the nutrient solution. However, the E. coli population declined naturally over the weeks following the inoculation, independent of the UV-C treatment. Survival of E. coli beyond one week is limited in the nutrient solution. Still, UV-C treatment has the potential to be used as a preventative safeguard for the microbial safety of the hydroponic production system by reducing contamination within the nutrient solution during crop growth. This can help maintain the safety of hydroponically grown fresh produce and reduce the likelihood of future outbreaks.http://www.sciencedirect.com/science/article/pii/S0362028X25001279E. coliFood safetyHydroponicsRomaine lettuceUVWater treatment
spellingShingle Markanna Moore
Teng Yang
Majid Jaberi Douraki
Cary Rivard
Eleni Pliakoni
Londa Nwadike
Manreet Bhullar
Effect of Ultraviolet Water Treatment on Survival and Growth of Escherichia coli in Recirculating Hydroponic Systems
Journal of Food Protection
E. coli
Food safety
Hydroponics
Romaine lettuce
UV
Water treatment
title Effect of Ultraviolet Water Treatment on Survival and Growth of Escherichia coli in Recirculating Hydroponic Systems
title_full Effect of Ultraviolet Water Treatment on Survival and Growth of Escherichia coli in Recirculating Hydroponic Systems
title_fullStr Effect of Ultraviolet Water Treatment on Survival and Growth of Escherichia coli in Recirculating Hydroponic Systems
title_full_unstemmed Effect of Ultraviolet Water Treatment on Survival and Growth of Escherichia coli in Recirculating Hydroponic Systems
title_short Effect of Ultraviolet Water Treatment on Survival and Growth of Escherichia coli in Recirculating Hydroponic Systems
title_sort effect of ultraviolet water treatment on survival and growth of escherichia coli in recirculating hydroponic systems
topic E. coli
Food safety
Hydroponics
Romaine lettuce
UV
Water treatment
url http://www.sciencedirect.com/science/article/pii/S0362028X25001279
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