Efficacy of Beef Carcass Surface Trimming to Reduce or Eliminate Escherichia coli O157:H7 Surrogates from Subsequent Subprimals

Abstract

This study was conducted to determine the effectiveness of trimming the original external carcass surfaces from subprimals during fabrication on the reduction of surrogates for Escherichia coli O157:H7. Carcass sides from five cattle (n = 10 sides) were inoculated along the pattern hide opening before entering the blast chill cooler with a gelatin slurry containing a bacterial cocktail of three rifampicin-resistant, nonpathogenic E. coli Biotype I strains. Following a 48 h chill, sides were fabricated to produce eight subprimals (brisket, chuck, clod, rib, bottom round, top sirloin, short loin, and inside round). Microbiological samples were taken from the original carcass fat surface area, initial lean surface area, trimmed fat surface area (where applicable), and trimmed lean surface area (where applicable). Trimming of the external fat surfaces reduced (P < 0.05) microbiological counts on the newly exposed lean surfaces of all eight subprimals during fabrication. However, these data also indicated that fat and lean surfaces that were not initially exposed to contamination became contaminated during the fabrication process. Trimming external surfaces reduces levels of pathogens, but under normal fabrication processes, pathogens may still be spread to the newly exposed surfaces.