title: Quantifying the sensitivity of scent detection dogs to identify fecal contamination on raw produce.
abstract: Consumption of raw produce commodities has been associated with foodborne outbreaks in the United States. In a recent Centers for Disease Control and Prevention report outlining the incidence of food-related outbreaks from 1998 to 2008, produce of all kinds were implicated in 46% of illnesses and 23% of deaths. Methods that quickly identify fecal contamination of foods, including produce, will allow prioritization of samples for testing during investigations and perhaps decrease the time required to identify specific brands or lots. We conducted a series of trials to characterize the sensitivity and specificity of scent detection dogs to accurately identify fecal contamination on raw agricultural commodities (romaine lettuce, spinach, cilantro, and roma tomatoes). Both indirect and direct methods of detection were evaluated. For the indirect detection method, two dogs were trained to detect contamination on gauze pads previously exposed to produce contaminated with feces. For the direct detection method, two dogs were trained to identify fecal contamination on fresh produce. The indirect method did not result in acceptable levels of sensitivity except for the highest levels of fecal contamination (25 g of feces). Each dog had more difficulty detecting fecal contamination on cilantro and spinach than on roma tomatoes. For the direct detection method, the dogs exhibited >75% sensitivity for detecting ≥0.25 g of feces on leafy greens (cilantro, romaine lettuce, and spinach) and roma tomatoes, with sensitivity declining as the amount of feces dropped below 0.025 g. We determined that use of a scent detection dog to screen samples for testing can increase the probability of detecting ≥0.025 g of fecal contamination by 500 to 3,000% when samples with fecal contamination are rare (≤1%).
authors.affiliation: Western Institute for Food Safety and Security, School of Veterinary Medicine, University of California, 1089 Veterinary Medicine Drive, Davis, California 95616, USA.
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Partyka
authors.affiliation: Western Institute for Food Safety and Security, School of Veterinary Medicine, University of California, 1089 Veterinary Medicine Drive, Davis, California 95616, USA.
authors.forename: Ronald F
authors.initials: RF
authors.lastname: Bond
authors.affiliation: U.S. Food and Drug Administration, Office of Food and Veterinary Medicine, Silver Spring, Maryland 20993, USA.
authors.forename: Jeff
authors.initials: J
authors.lastname: Farrar
authors.affiliation: Falco K-9 Academy, 615 Berry Street, Brea, California 92821, USA.
authors.forename: Andy
authors.initials: A
authors.lastname: Falco
authors.affiliation: U.S. Food and Drug Administration, Office of Partnerships, Rockville, Maryland 20857, USA.
authors.forename: Barbara
authors.initials: B
authors.lastname: Cassens
authors.affiliation: U.S. Food and Drug Administration, Office of Regulatory Affairs, Los Angeles District Office, Irvine, California 92620, USA.
authors.forename: Alonza
authors.initials: A
authors.lastname: Cruse
authors.affiliation: Western Institute for Food Safety and Security, School of Veterinary Medicine, University of California, 1089 Veterinary Medicine Drive, Davis, California 95616, USA.
authors.forename: Edward R
authors.initials: ER
authors.lastname: Atwill
mesh_terms: D000818:Animals; D004285:Dogs / Q000502:physiology*; D005243:Feces; D005506:Food Contamination / Q000032:analysis*; D005513:Food Inspection / Q000379:methods / Q000592:standards*; D057230:Limit of Detection; D012680:Sensitivity and Specificity; D012903:Smell / Q000502:physiology*; D014481:United States; D014675:Vegetables / Q000737:chemistry