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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Meat Safety and Quality » Research » Publications at this Location » Publication #391258

Research Project: Holistic Tactics to Advance the Microbiological Safety and Quality of the Red Meat Continuum

Location: Meat Safety and Quality

Title: The effects of the administration of a Saccharomyces cerevisiae direct-fed microbial on the prevalence of Salmonella in bovine mesenteric lymph nodes

item HABIB, KELLEN - Kansas State University
item Schmidt, John
item NICHOLS, CODY - Legacy Animal Nutrition
item KANG, QING - Kansas State University
item Bosilevac, Joseph - Mick
item Harhay, Dayna
item GRAGG, SARA - Kansas State University

Submitted to: International Association for Food Protection Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2023
Publication Date: 7/31/2022
Citation: Habib, K., Schmidt, J.W., Nichols, C.A., Kang, Q., Bosilevac, J.M., Harhay, D.M., Gragg, S.E. 2022. The effects of the administration of a Saccharomyces cerevisiae direct-fed microbial on the prevalence of Salmonella in bovine mesenteric lymph nodes. [Abstract]. International Association for Food Protection Proceedings. P1-83.

Interpretive Summary:

Technical Abstract: Introduction: Contamination of ground beef products with Salmonella harbored within lymph nodes of cattle presents a potential risk to public health and pre-harvest interventions aimed at reducing Salmonella in cattle prior to entering the abattoir may improve public health. Purpose: This study was designed to determine if Saccharomyces cerevisiae (SC) can reduce the prevalence and/or concentration of Salmonella in mesenteric lymph nodes (MLNs) of feedlot cattle at harvest when fed at 3.0x1010 CFU/head/day in finishing diets. Methods: Cattle at a commercial feedlot were fed finishing diets, with treatment cattle receiving diets supplemented with SC and control animals receiving no supplemental SC. A total of 427 MLNs were collected by abattoir personnel at harvest from control (N=217) and treated (N=210) cattle. MLNs were trimmed, boiled, smashed, and homogenized with tryptic soy broth (TSB) to prepare a lymph node homogenate (LNH). The LNH was enumerated on Enterobacteriaceae petrifilm®, which were replica-plated to xylose lysine desoxycholate (XLD) agar. The LNH was then enriched, subjected to immunomagnetic separation with a secondary enrichment in rappaport-vassiliadis (RV) broth, and streaked for isolation on XLD. Colonies were confirmed as Salmonella via PCR. Results: Overall Salmonella prevalence of the 427 MLNs was 13.8% and the model-adjusted Salmonella prevalence was 12.3% and 10.6% for MLNs from control and treated cattle, respectively (P=0.7763). The odds ratio comparing prevalence from control and treated cattle MLNs was 0.85, suggesting that the treatment diet reduced the odds of Salmonella prevalence by 15%. However, because of the wide confidence interval, efficacy could not be determined. Diet did not impact Salmonella concentration (P>0.05). Significance: While the data suggest that SC may impact Salmonella prevalence in MLNs, future research should include a larger sample size from cattle that likely have a higher Salmonella prevalence to increase power and the likelihood of detecting a treatment effect.