University of California-Davis, Western Center for Food Safety"> Presentation: Assessment of Zoonotic Risks in Aquaponic Lettuce Production: A Prototype for Experimental Greenhouse Trials (IAFP 2017) University of California-Davis, Western Center for Food Safety">

T1-03 Assessment of Zoonotic Risks in Aquaponic Lettuce Production: A Prototype for Experimental Greenhouse Trials

Monday, July 10, 2017: 9:00 AM
Room 15 (Tampa Convention Center)
Elizabeth Antaki , Western Center for Food Safety, University of California-Davis , Davis , CA
Geoffrey Mangalam , Western Center for Food Safety, University of California-Davis , Davis , CA
Peiman Aminabadi , Western Center for Food Safety, University of California-Davis , Davis , CA
Fernanda de Alexandre Sebastião , University of California-Davis , Davis , CA
Esteban Soto , University of California-Davis , Davis , CA
Beatriz Martínez López , University of California-Davis , Davis , CA
Fred Conte , University of California-Davis , Davis , CA
Sarah Taber , Boto Waterworks, LLC , Gainesville , FL
Michele Jay-Russell , University of California-Davis, Western Center for Food Safety , Davis , CA
Introduction:  Aquaponics is the integration of aquaculture and hydroponics that is now being used as a model for sustainable food production. Because fresh vegetables are usually consumed raw, especially leafy greens, there are concerns about food safety and zoonotic risks from fish waste for this emerging industry.

Purpose:  The purpose of this study was to develop an experimental recirculating aquaponic system (RAS) prototype and to then investigate persistence and transfer via root uptake of an attenuated Salmonella strain in a RAS used for leafy green production in order to gain the knowledge of good agricultural practices (GAPs) specific for aquaponic practitioners to reduce the potential for foodborne illnesses due to product contamination.

Methods: Initially, the lethal and infective dose of Salmonella enterica serovar Typhimurium (aPTVS177) strain to naive tilapia (Oreochromis spp.) fingerlings was determined by intragastric challenge. Then using two nonlethal doses (105 and 109CFU), a second group of fish was challenged and used in the laboratory controlled RAS utilizing hydroponic lettuce. Salmonellawas quantified in the system components (tanks, tubing, plant bed substrate), fish waste, and lettuce plants (roots and plants) using microbiological and molecular analysis.

Results: Only the three highest inoculums (108 to 1010 CFU) yielded positive isolation of Salmonella from fish. In the second challenge, at least one of the RAS holding Salmonella-infected fish was positive for the presence of Salmonella at the tested time points. On day 42, two fish from one RAS, inoculated with a high dose (10CFU), had positive stomach and intestinal tissues with concentrations ranging from 0.36 to 160 MPN/g of tissue (MPN; most probable number). None of the plants or other tank system components were positive.

Significance: This study described a potential system to investigate foodborne diseases in a RAS and identified potential strategies to reduce the risk of bacterial contamination if exposed to contaminated fish waste, leading to the foundation of GAPs.