4, 2009 USDA’s Food Safety and Inspection Service issued a Directive on verifying sanitary dressing and process
control procedures in slaughter operations of cattle (http://www.fsis.usda.gov/OPPDE/rdad/FSISDirectives/6410.1.pdf). This Directive which goes into effect
on June 1, 2009 is intended to assure that the beef slaughter process includes
effective microbial interventions that reduce the risk of microbiological
contamination on beef carcasses. It will certainly force beef packers to
rethink their pathogen control strategies.
before the 1993 E. coli O157:H7 outbreak, much of
the emphasis on beef safety has focused on slaughter interventions. This
approach makes sense because at this point in the process, all of the
microbiological contamination is limited to the surface of the carcass.
The meat inside the carcass is completely free of bacteria until it is
contaminated during fabrication. The major vectors of contamination
during beef slaughter are hide removal, evisceration and the slaughter
environment. Much can be done to control contamination from each of these
vectors during the slaughter process. Hide removal and evisceration can
be done in a sanitary manner and any visible contaminants can be removed
using steam vacuuming. Most beef
slaughter plants utilize a combination of thermal pasteurization and
organic acid treatments to further reduce microbiological contamination.
Environmental contamination can be controlled by treating the air using
low levels of vaporized Hydrogen Peroxide.
this system should completely address microbiological contamination. It
has resulted in improvements over the past several years, but
unfortunately, problems with microbiological contamination on beef
carcasses still exist. I see two potential problems with slaughter based
interventions. (1) The time available to apply interventions is limited.
Thermal and chemical interventions may not have the required residence
time to achieve optimum effectiveness. And (2) the carcass chilling
process may contribute to microbiological growth if carcasses are not
properly spaced and adequately chilled.
the most effective point in the process for an additional intervention is
during the chilling process. There is ample time for an intervention
since carcass chilling usually requires 24-48 hours. An effective
intervention applied for a sufficient length of time may allow for the
validated pasteurization of carcass surfaces. Hopefully, USDA’s focus on
slaughter interventions and process control will accelerate the
development of post-slaughter pasteurization technologies. If this can be
achieved, the beef industry could finally claim victory over the problem
of E. coli O157:H7.