Preslaughter Events Do Not Impact Salmonella Prevalence in Turkeys

Two studies, which were conducted to study the effect of pre-slaughter events on the overall prevalence of Salmonella spp. in turkeys, demonstrate that preslaughter practices (feed withdrawal, catching, loading, transportation, and holding) do not significantly affect the prevalence of Salmonella in market-age turkeys. This contrasts with the increase in Salmonella prevalence reported for hogs and broilers.

Introduction

Two studies were conducted to study the effect of preslaughter events on the overall prevalence of Salmonella spp. in turkeys.

Materials and Methods

Study 1. To determine if perimarketing events, such as transport and holding at the slaughterhouse, impact Salmonella prevalence in turkeys. Floors of transport crates were swabbed after loading and prior to transport at the farm (Time 1, n = 100 swabs per trial) and after transport and holding at the abattoir (Time 2, n = 100 swabs per trial). In addition, environmental samples were taken at each of the six premises (n = 25 per premise) as well as in the holding shed at the abattoir (n = 25 samples per trial). Based on crate floor swabs collected pre- and post-transport, when individual farms were analyzed only one premise exhibited a statistically significant change as seen by decline in Salmonella prevalence post-transport (P < 0.01). When data from all farms were combined, Salmonella was recovered more frequently from swabs collected pre-transport at loading on-farm (Time 1, 47.6%) than from swabs collected post-transport (Time 2, 39.7%, P < 0.01).

Study 2. To compare the prevalence of Salmonella in market-age turkeys on-farm and at slaughter (i.e., before and after feed withdrawal, catching, loading, transportation, and pre-slaughter holding). Birds (n = 30) were randomly selected from each of six commercial turkey production flocks, euthanized and necropsied on-farm. Birds (n = 30) from the same production barn were randomly sampled at slaughter. Individual samples collected included: crop, ceca, liver/gall bladder, and spleen.

Results and Discussion

Study 1. When data for individual flocks were analyzed, only Flock 2 showed a decline in Salmonella prevalence post-transport. When data for all farms were combined, Salmonella was recovered more frequently from swabs collected pre-transport at loading on-farm (Time 1, 47.6%) than from swabs collected post-transport (Time 2, 39.7%, P < 0.01).

Study 2. All flocks studied were positive for Salmonella at slaughter. At both sampling points, the overall prevalence was 33.3%. No statistical difference was found between the overall prevalence found on-farm and at slaughter. Diverging prevalence estimates were obtained based on the different sample types collected on-farm and at slaughter with cecal content samples showing the highest relative sensitivity (73.3% and 68.3%, respectively).

Acknowledgments

We thank Michelle Andersen, Brad Bearson, Chris Bouchard, Jared Gailey, V. Alejandra Morales, Adrienne Norgrant, Susan Regen, Robert Schneider, and Wayne Muraoka for their camaraderie and technical support. The cooperation of the turkey producers for access to their flocks and to the processing plant was critical to the success of this project. This study was partially funded by the Midwest Poultry Federation and the Merck-Merial Summer Research Program.

Publications

Rostagno, M.H., et al. 2006. Salmonella prevalence in market-age turkeys on farm and at slaughter. Poultry
Science (in press).

Wesley I.V., et al. 2005. The effect of perimarketing events on the prevalence of Salmonella in market weight
turkeys. Journal of Food Protection (in press)

Wesley, I.V., et al. 2005. The effect of transport and holding on Salmonella and Campylobacter. World Poultry
21(9):28ï¿½30.

Table 1. Percent recovery of Salmonella from transport crates and environment on-farm and at the abattoir for six individual flocks (Study 1).

* Prevalence pre-transport higher than post-transport (P < 0.01).

Table 2. Percentage Salmonella enterica prevalence in turkeys (Study 2).

ND, not done.

Authors: Marcos Rostagno, National Animal Diseases Center; Darrell Trampel, Extension Poultry Veterinary; Fernando Rivera, University of Zuila, Venezuela; Ellen Harbaugh, National Animal Disease Center; Irene V. Wesley, National Animal Disease Center; and H. Scott Hurd, National Animal Disease Center
A.S. Leaflet R2206 - Iowa State University and USDA Poultry Science Day Report

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Preslaughter Events Do Not Impact Salmonella Prevalence in Turkeys