Effects of Postexsanguination Dehairing on the Microbial Load and Visual Cleanliness of Beef Carcasses

Ten grain-fed steers or heifers were selected to be dehaired at slaughter, while another 10 cattle (of the same kind) were slaughtered and dressed without dehairing. The carcasses of these animals were evaluated for bacterial contamination (aerobic plate count [APC], total coliform count [TCC], Escherichia coli biotype I, and count and presence of Salmonella spp. and Listeria monocytogenes ) after sampling from the brisket, flank, and inside round at each of three sites (after dehiding, after evisceration, and after final carcass washing). Visual defects (hairs and specks) and weight associated with trimmings were also evaluated. Overall, there were no major differences in APC, TCC, or E. coli counts between samples from dehaired cattle and those from conventionally slaughtered animals. Dehaired carcasses had fewer (P < 0.05) visible specks and fewer total carcass defects before trimming (but not after trimming) than did carcasses of conventionally slaughtered animals. There were fewer (P < 0.05) visible hairs both before and after trimming on dehaired carcasses than on conventionally slaughtered animals, and no hair clusters were observed on dehaired carcasses. The average amount of trimmings removed to meet zero tolerance specifications in carcasses of conventionally slaughtered cattle was almost double (2.7 versus 1.4 kg) that required on dehaired animals, but due to large variation among plant personnel involved with trimming the carcasses, the difference was not significant (P > 0.05). Overall, dehairing reduced visual contamination evident on beef carcasses but did not decrease the overall bacterial load.