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Mitigation of Salmonella in Lymph Nodes using Pre-Harvest Interventions


The overall goal of this project is to mitigate Salmonella from the lymph nodes of cattle in order to protect public safety and human health. This goal will be met through the following objectives:
<ol> <LI>
Determine if supplementing cattle diets with a 109/head/day dose of Lactobacillus acidophilus NP51 will reduce Salmonella in lymph nodes at slaughter; and</LI> <LI>
Determine if lymph node contamination increases the risk of carcass contamination and/or trim from the carcass.</LI> </ol>
These objectives will be met by conducting a study utilizing a commercial feedyard in Texas in collaboration with Cargill Meat Solutions. Cattle will be housed in a commercial feedyard and treated animals will be fed a diet supplemented with 109 per head per day of NP51. Cattle will be harvested in the late summer/early fall when Salmonella prevalence has been traditionally at a peak. At harvest, subiliac and mandibular lymph nodes will be collected and analyzed for the presence of and quantify Salmonella using an Immunomagnetic separation methodology and colony transfer methods. Surrounding fat and other tissues around the nodes will also be collected to determine the amount of cross-contamination that may occur from the nodes to the carcass. Comparisons of the Salmonella prevalence in the control and treated animals will be conducted to determine if the direct-fed microbials significantly reduced the pathogen in the lymph nodes.

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Status (As of October 2012)<br/>

Research is on schedule. Cattle were scheduled for slaughter in September. At each slaughter event lymph nodes and surrounding fat samples were collected from selected cattle. The samples were transported on ice back to the laboratory for microbiological processing for both the presence and quantity of Salmonella.

Miller, Mark; Loneragan, Guy; Gragg, Sara; Echeverry, Alejandro; Brooks, Chance ; Brashears, Mindy; Schaefer, Dan; Nightingale, Kendra ; Harhay, Dayna
Texas Tech University
USDA - Agricultural Research Service
Cargill, Inc
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