|HARBAUGH, E - IOWA STATE UNIVERSITY
|TRAMPEL, D - IOWA STATE UNIVERSITY
|HOFF, S - IOWA STATE UNIVERSITY
|GRIFFITH, R - IOWA STATE UNIVERSITY
|HURD, H - IOWA STATE UNIVERSITY
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/11/2006
Publication Date: 4/11/2006
Citation: Harbaugh, E., Trampel, D., Wesley, I.V., Hoff, S., Griffith, R., Hurd, H.S. 2006. Rapid aerosol transmission of Salmonella among turkeys in a simulated holding-shed environment. Poultry Science. 85(10):1693-1699.
Interpretive Summary: Human salmonellosis causes nearly 1,343,000 cases of foodborne illness resulting in ~ 15,000 hospitalizations and ~ 500 deaths annually. Consumption of contaminated undercooked poultry is a major risk factor for human Salmonella infections. The goal of on-farm pathogen reduction strategies is delivery of turkeys to the abattoir with low levels of Salmonella. Controlling Salmonella contamination of turkeys prior to slaughter may include limiting the turkey’s exposure to bacteria in the last few hours prior to slaughter during the on-farm loading, transportation, and holding at the abattoir. After transport to the slaughterhouse, turkeys rest in a holding shed for an average of six hours prior to slaughter. We wished to establish if Salmonella transmission occurred during this interval. Results of these five studies with market weight turkeys indicated that indeed rapid air-borne transmission could occur in as little as two hours in the simulated the environment of the holding shed. Airborne Salmonella transmission may contribute to an increased number of contaminated birds entering the slaughter plant. Therefore, production steps that generate a large amount of dust, such as feed withdrawal, loading, transportation, and holding in the cooling shed, should be minimized.
Technical Abstract: Once turkeys arrive at the slaughter plant, they are held in large outdoor structures prior to slaughter. In hot humid weather, large commercial fans cool the birds during holding. The resultant air currents distribute a significant amount of dust to other turkeys. The dust created in this environment could be a factor in the number of Salmonella-contaminated turkeys entering slaughter plants. The objective of this study was to determine if rapid transmission of Salmonella in turkeys could occur from exposure to Salmonella-contaminated dust similar to what may be experienced in holding sheds or in other high dust environments prior to slaughter. In the first experiment, trials of three different concentrations of Salmonella (1.2 x 10**9 cfu/g, 2.6 x 10**7 cfu/g, 2.6 x 10**5 cfu/g) were conducted to determine if transmission of Salmonella enterica serovar Typhimurium var. typhimurium x4232 to turkeys two to four hours after exposure to contaminated feces is possible. Results showed that turkeys become infected after two hours of exposure to airborne contaminated feces with a concentration level of 2.6 x 10**5 S. Typhimurium/g. In the second experiment, one bank (five cages wide and three cages high) of turkeys was exposed to another bank of cages of S. Typhimurium-inoculated birds for two to four hours using a fan similar to the type in commercial cooling sheds. Results from this experiment demonstrated that birds are contaminated with S. Typhimurium after two hours of this type of exposure. Results of both studies implicate contaminated dust as a route of rapid airborne transmission of Salmonella in turkeys. Processes that generate significant dust prior to slaughter should be regarded as critical control points for Salmonella.