Abrogation of Salmonella and E. coli O157:H7 in Feedlot Cattle Fed

Salmonella and E. coli O157:H7 are perfidious problems for the beef industry. Asymptomatic fecal shedding of these pathogens contaminates the hide and cadaver. Furthermore, Salmonella are unique in their ability to penetrate lymph nodes leading to the post-harvest contagion of ground beef. These contaminations yield the two most significant food safety hazards associated with the consumption of beef. Herein, we report the anti-Salmonella and anti-E. coli O157:H7 effects of a novel Saccharomyces cerevisiae fermentation prototype fed to feedyard cattle. Cattle fed PRT were compared to those fed a combination of monensin, tylosine, and a direct-fed microbial- a standard conventional practice in the U.S. beef industry. 

In this investigator-blinded study, 1,495 feedlot heifers (300-400 kg) were fed PRT (n=747 heifers) or the standard industry diet (PC; n=748 heifers) without PRT for 125-146 days prior to slaughter. At the abattoir, fecal swabs were obtained from 400 animals (n=200/group) and subjected to selective culture for enumerating Salmonella and E. coli O157:H7. Additionally, subiliac lymph nodes were obtained from 400 carcasses for enumeration of Salmonella spp. Salmonella isolated from the feces and lymph nodes were subjected to a virulence assay and some antibiotic susceptibility and Salmonella serovar testing.