Location: Meat Safety & Quality Research
Title: Escherichia coli O157:H7 and Salmonella in Small Processing Plants and the Effect of Feeding Wet Distillers Grains with Solubles on E. coli O157:H7 Authors
|Koohmaraie, Mohammad - FORMER ARS EMPLOYEE|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 27, 2009
Publication Date: March 4, 2009
Citation: Bosilevac, J.M., Wells, J., Arthur, T.M., Kalchayanand, N., Shackelford, S.D., Berry, E.D., Bono, J.L., Harhay, D.M., Wheeler, T.L., Koohmaraie, M. 2009. Escherichia coli O157:H7 and Salmonella in Small Processing Plants and the Effect of Feeding Wet Distillers Grains with Solubles on E. coli O157:H7 [abstract]. NCBA Beef Industry Safety Summit, San Diego, CA, March 4-6, 2009. Interpretive Summary: Interpretive summary not required.
Technical Abstract: This is a summary of two recently completed Beef Checkoff funded projects aimed at better understanding the dynamics of pathogens entering the beef production chain. The first project examined the prevalence of E. coli O157:H7 and Salmonella in abattoirs that process less than 1,000 head of cattle per day, and the second project examined E. coli O157:H7 prevalence among feedlot steers fed diets with or without wet distillers grains with solubles (WDGS). The first project was undertaken because a significant portion of beef is produced in small beef processing plants, but there is little data on the prevalence and levels of E. coli O157:H7 and Salmonella in these plants. This lack of data was addressed by analyzing samples collected from hides (n=1995) and carcasses (n=1995) at seven small processing plants located across the U.S. The incoming load of pathogens was similar across all plants. The overall hide prevalence of E. coli O157:H7 and Salmonella was 71% and 91%, respectively. Twelve percent of hides had E. coli O157:H7 at enumerable levels (>40 CFU/100 cms), while 36% of hides had Salmonella at enumerable levels. The transfer of pathogens to carcasses during hide removal varied by plant. The prevalence of E. coli O157:H7 on pre-evisceration carcasses was 33%, with 2% at an enumerable level (>0.8 CFU/100 cms), and Salmonella prevalence on pre-evisceration carcasses was 58%, with 8% at an enumerable level. Reduced levels of pathogens on carcasses were noted among small processors that had incorporated a hide-directed intervention. The results obtained are comparable to those observed previously for larger processors, showing that smaller beef processors face and address the same challenges as larger beef processors. To address the objective of the second project, feedlot steers (n=603) were randomly assigned to diets with and without WDGS and then hide and fecal samples were collected monthly and analyzed for E. coli O157:H7. In the growing phase (diets of 0 vs. 14% WDGS), fecal prevalence for E. coli O157:H7 in WDGS fed steers was twice that of control steers (P < 0.001). In the finishing phase (diets of 0 vs. 40% WDGS), average prevalence in feces and on hides was higher for WDGS fed cattle (P < 0.001). The average percentage of fecal E. coli O157:H7 enumerable samples during the finishing phase for WDGS fed cattle was 2.7% compared to 0.1% for corn fed control cattle (P < 0.001). The average percentage of E. coli O157:H7 enumerable hide samples was not different between diets, but the WDGS fed cattle had higher levels (P < 0.05). In addition, cattle fed WDGS had higher levels of generic E. coli (P < 0.001), higher pH (P < 0.001), and lower concentrations of L-lactate (P < 0.001) in feces. These results indicate that feeding 40% WDGS may increase the level and prevalence of E. coli O157:H7 in feedlot cattle, but the magnitude of the difference detected in this study may have been affected by the low prevalence in control cattle.