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

Abstract

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.

Efficacy of Ozonated and Electrolyzed Oxidative Waters To Decontaminate Hides of Cattle before Slaughter

“…Washing the hides of cattle with water did not result in significant reductions in hide or carcass contamination (9,20). The inclusion of an antimicrobial (cetylpyridinium chloride) or a decontamination step (chemical dehairing) was required to obtain improvements in cleanliness of hides and subsequent preevisceration carcasses, but use of antimicrobials (6,20) or chemical dehairing (26) did not have a significant effect. Later use of chemical dehairing on a large sample in an industry setting did clearly demonstrate the efficacy of hide decontamination and improved carcass cleanliness (21).…”

Antibacterial activity of decontamination treatments for cattle hides and beef carcasses

“…by more than four orders of magnitude (Carlson et al 2008b;Castillo, Dickson, Clayton, Lucia, & Acuff, 1998a). But under commercial conditions, chemical dehairing yielded hardly any reduction for naturally occurring aerobic bacteria or Enterobacteriaceae (Nou et al, 2003;Schnell et al, 1995). …”

On-line real time aid to the verification of CCP compliance in beef slaughter HACCP systems

“…Schnell et al (1995) concluded that as far as dehairing carcasses were concerned the absence of visual contamination was not well-correlated with the bacterial cleanliness of beef carcasses, although the study did propose that over an extended period of time, using exclusive processing facilities for dehaired animals, it could be anticipated that removing the dirt, faeces and hair prior to hide removal should decrease carcass surface pathogens. Gill, Mc Ginnis, and Baldoni (1995b) concluded that commercial trimming and standard washing operations were not eVective means of decontaminating beef carcasses.…”

“…Whilst not deWnitively pinpointing to lower carcass bacterial loading the absence of visible faecal contamination does reXect a greater tendency towards compliance of a more holistic hygienic process, the institutionalisation within the slaughterhouse of a more robust GHP/GMP pre-requisite program and the reduction in contamination due to aerosols, equipment and personnel [often cited as important sources of carcass bacterial contamination, Le Jeune and Christie (2004), Schnell et al (1995)]. Certainly, Hudson, Mead, and Hinton (1996) identiWed a lowering of microbiological contamination with the implementation of a robust GHP/GMP pre-requisite program.…”