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E. coli contamination on beef cattle hides continues to be a major beef safety issue for the
industry. Reducing pathogen loads as they come into the harvest facility is one step in a multiple
step intervention process. Intervention methods in place within the facility will be enhanced if
pathogen loads are mitigated before the cattle enter the harvest facility. <P>
The overall objective of this study was to evaluate the effects of three different doses of NP51
and the combination of NP51 and NP45 fed to finishing beef cattle on the prevalence of E. coli
in the feces and on the hides.
Findings: This study was led by Texas Tech University to evaluate supplementing finishing beef cattle with Lactobacillus-based direct-fed microbials as a pre-harvest food safety intervention strategy. Our objective was to evaluate the effects of three different doses of Lactobacillus acidophilus strain NP 51 and a combination treatment of NP51 and NP45 on prevalence of Escherichia coli O157 in finishing beef cattle. Three hundred steers were used in the study which was conducted at the Texas Tech University Burnett Center for Beef Cattle Research and Instruction. Cattle received one of five treatments throughout the feeding period: treatments were based on high, medium, and low dose levels of NP51, a combination of NP51 and NP45, or no DFM (control). All DFM treatments included Propionibacterium freudenreichii to enhance animal performance. Individual rectal fecal samples were collected on arrival and every 28 days throughout the feeding period. Hide samples were also collected at the end of the feeding period to determine the prevalence of E. coli O157 hide carriage immediately prior to harvest. Cattle receiving a high level dose of NP51 were, overall, 77% less likely to shed E. coli O157 in their feces relative to those receiving the control diet. While supplementing cattle with lower doses of NP51 resulted in decreased fecal prevalence of the organism, using the high-level dose of NP51 was most effective. A lower percentage of cattle were carrying detectable E. coli O157 on their hide among those receiving DFM compared to the control groups. Supplementing cattle with Lactobacillus acidophilus strain NP51 based DFM continues to show promise as a pre-harvest food safety intervention strategy to control E. coli O157 in finishing beef cattle. The effectiveness of using the high-level dose of NP51 may make it most advantageous in improving food safety pre-harvest.
<P> For complete projects details, view the <a href="http://www.beefresearch.org/CMDocs/BeefResearch/Reduction%20of%20E.%20c…; target="_blank">Project Summary. </a>