Mitigation of Human Pathogen Contamination in Lettuce and Basil Produced in NFT Hydroponic System

Abstract

ObjectivesThe objective of this study was to evaluate the efficacy of sanitizers to eliminate pathogens from the nutrient solution, productions surfaces, and their effect on quality (yield, color) of lettuce and basil grown in hydroponic Nutrient Film Technique (NFT) systems.MethodsSanitizers' efficacy to eliminate Salmonella typhimurium from the nutrient solution and hydroponic surfaces was evaluated. Pathogen enumeration and surface swabs were collected for 13 treatments post-inoculation (∼104 CFU/ml). A split-plot within a randomized complete block study design compared the treatments (SaniDate12.0; 200ppm, and sodium hypochlorite;100ppm, 200ppm) on the health of lettuce and basil.ResultsOf all identified sanitizers approved for use in food production, SaniDate 12.0 and Sodium-hypochlorite 100 ppm and 200 ppm effectively eliminated Salmonella typhimurium from nutrient solution and surfaces and were tested in commercial units with lettuce and basil. The average plant weight at harvest (5weeks post-transplant) for untreated controls was 181.65 ± 10.89 g/lettuce and 78.88 ± 21.4 g/basil. All sanitizer treatments negatively impacted lettuce quality, with 200 ppm- sodium-hypochlorite treated crops severely affected (92.05% reduction/lettuce and 83% reduction/basil). Crops treated with SaniDate 12.0 recovered fully (117.4% lettuce and 104.3% basil) by harvest (29 days post-treatment) compared to hypochlorite treatments. ConclusionsSaniDate 12.0 was the only suitable commercial sanitizer for developing water sanitation protocols in hydroponics. The validation of its effectiveness against the human pathogens in the system with crops, as well as nutrient content analysis in ongoing.Funding SourcesOhio Department of Agriculture grant.