Rapid aerosol transmission of Salmonella among turkeys in a simulated holding-shed environment.
Once turkeys arrive at Midwest processing plants, they are usually held in large open-sided sheds for 1 to 4 h, waiting to be unloaded. In hot, humid weather, large fans are used to cool the birds. The resultant air currents distribute a significant amount of dust to the 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 3 different concentrations of Salmonella (1.2 x 10(9), 2.6 x 10(7), and 2.6 x 10(5) cfu/g) were conducted to determine if transmission of Salmonella enterica serovar Typhimurium var. typhimurium(chi)4232 to turkeys 2 to 4 h after aerosol exposure to contaminated feces is possible. Results showed that turkeys became infected after 2 h of exposure to airborne-contaminated feces with a concentration level of 2.6 x 10(5) cfu of Salmonella Typhimurium/g. In the second experiment, consisting of 3 trials, 1 bank (5 cages wide and 3 cages high) of turkeys (n = 15 birds per trial) was exposed to another bank of cages of S. Typhimurium-inoculated (n = 15) birds for 2 to 4 h using a fan similar to the type in processing-plant cooling sheds. Results from this experiment demonstrated that birds could be contaminated with S. Typhimurium after 2 h 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.
Harbaugh
E
E
Preharvest Food Safety and Enteric Diseases Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, Iowa 50011, USA.
Trampel
D
D
Wesley
I
I
Hoff
S
S
Griffith
R
R
Hurd
H S
HS
D000003:Abattoirs; D000336:Aerosols; D000389:Air Conditioning / Q000379:methods*; D000818:Animals; D004391:Dust; D005243:Feces; D006799:Housing, Animal; D008297:Male; D012475:Salmonella / Q000302:isolation & purification*; D012481:Salmonella Infections, Animal / Q000635:transmission*; D013997:Time Factors; D014422:Turkeys / Q000382:microbiology* / Q000502:physiology
D000336:Aerosols; D004391:Dust