{"title":"Effect of Ultraviolet Water Treatment on Survival and Growth of E. coli in Recirculating Hydroponic Systems.","authors":"Markanna Moore, Teng Yang, Majid Jaberi Douraki, Cary Rivard, Eleni Pliakoni, Londa Nwadike, Manreet Bhullar","doi":"10.1016/j.jfp.2025.100575","DOIUrl":null,"url":null,"abstract":"<p><p>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 non-hydroponic 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 log<sub>10</sub> 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.</p>","PeriodicalId":15903,"journal":{"name":"Journal of food protection","volume":" ","pages":"100575"},"PeriodicalIF":2.1000,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of food protection","FirstCategoryId":"97","ListUrlMain":"https://doi.org/10.1016/j.jfp.2025.100575","RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"BIOTECHNOLOGY & APPLIED MICROBIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
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 non-hydroponic 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.
期刊介绍:
The Journal of Food Protection® (JFP) is an international, monthly scientific journal in the English language published by the International Association for Food Protection (IAFP). JFP publishes research and review articles on all aspects of food protection and safety. Major emphases of JFP are placed on studies dealing with:
Tracking, detecting (including traditional, molecular, and real-time), inactivating, and controlling food-related hazards, including microorganisms (including antibiotic resistance), microbial (mycotoxins, seafood toxins) and non-microbial toxins (heavy metals, pesticides, veterinary drug residues, migrants from food packaging, and processing contaminants), allergens and pests (insects, rodents) in human food, pet food and animal feed throughout the food chain;
Microbiological food quality and traditional/novel methods to assay microbiological food quality;
Prevention of food-related hazards and food spoilage through food preservatives and thermal/non-thermal processes, including process validation;
Food fermentations and food-related probiotics;
Safe food handling practices during pre-harvest, harvest, post-harvest, distribution and consumption, including food safety education for retailers, foodservice, and consumers;
Risk assessments for food-related hazards;
Economic impact of food-related hazards, foodborne illness, food loss, food spoilage, and adulterated foods;
Food fraud, food authentication, food defense, and foodborne disease outbreak investigations.