Mitigation of Salmonella in Lymph Nodes using Pre-Harvest Interventions

The project evaluated supplementation of cattle diets with Lactobacillus acidophilus NP51 to reduce Salmonella in lymph nodes at slaughter and concluded high doses of NP51 could be a viable intervention.

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Objectives

1. Determine if supplementing cattle diets with a 10⁹/head/day dose of Lactobacillus acidophilus NP51 will reduce Salmonella in lymph nodes at slaughter.
2. Determine if lymph node contamination increases the risk of carcass contamination and/or trim from the carcass.

Conclusions

The results indicated a 25% reduction (p=0.005) in Salmonella prevalence in the subiliac lymph nodes of cattle fed a 10⁹/head/day dose of NP51.  A significant reduction (p<0.05) in Salmonella concentration in the subiliac lymph nodes was also observed when compared to the control cattle.  Our team has concluded that this direct-fed microbial treatment with the high dose of NP51 is a viable intervention to reduce the carriage of Salmonella in the lymph nodes of cattle.  This could potentially aid in reducing ground beef contamination from lymph nodes harboring Salmonella.  If so, a decrease in the prevalence of Salmonella in lymph nodes could help to protect public health by helping to decrease the illnesses caused by ground beef.

Deliverables

The use of well characterized direct-fed microbial interventions such as Lactobacillus acidophilus NP51 can have a positive impact on public health by reducing Salmonella in the beef supply.  The product is currently available from Nutrition Physiology Company, LLC as “Bovamine Defend”.  This pre-harvest intervention is an additional hurdle when combined with current pre- and post-harvest interventions.  In most situations, the efficacy of post-harvest interventions may be greater if the pathogen load coming into the processing plant is less due to effective pre-harvest interventions as described in this research.  However, current in-plant interventions such as hot water washes, chemical treatments, etc do not impact the Salmonella harbored and protected inside the lymph nodes.