can reduce the microbial load but do not
destroy all pathogens. Overall effectiveness,
due to the high pH, is similar to that
achieved by organic acids (Fratamico et al.,
1996). More information on carcass sanitiz-
ers is included in Chapter 17.
Carcass rinsemethods lack effectiveness in
killing microorganisms because of the inef-
fective penetration of water to all of the con-
taminated surfaces. Hair, feathers, and scale
follicles are large enough to hide bacteria but
too small to admit a liquid wash or spray. An
unrealistic high water pressure is needed to
overcome the capillary pressure in a pore
large enough to house a bacterium. The fate
of E. coli O157:H7 cells that have been
removed from carcasses by rinses with sani-
tizing agents is not understood fully. It
appears that the exposure times associated
with carcass sanitizing are too short to
achieve any significant direct inactivation.
The primary effect of carcass rinses may be
the physical removal of microorganisms
(Buchanan and Doyle, 1997).
Thermal sanitizingis the simplest form of
pasteurization and may be more effective
than chemical sanitizing in the destruction of
pathogens on carcasses. However, hot water
at or above 82°C is effective, as is steam pas-
teurization. Hot water washes are usually
designed as tunnels with conveyors that
move products through hot water or steam
through submersion or showering. The tem-
perature increase reduces a number of bacte-
ria (usually 3 or more log reduction). Steam
or water is incorporated in most animal har-
vesting operations to reduce pathogens on
the carcass surface (Maddock, 2003).
Steam pasteurizationinvolves passing car-
casses through a tunnel that is approximately
12 m long, where large quantities of steam
are applied to the carcass surface. A large
percentage of bacteria on the carcass surface
is destroyed, and the risk of enteric
pathogens such as E. coliO157:H7 and Sal-
monella is reduced. This process involves
three stages: (1) drying the washed carcass
with forced filtered air; (2) immersion of the
carcass in pressurized steam in a steam cabi-
net to envelop the entire surface area for 6 to
8 seconds to raise the temperature to approx-
imately 82°C; and (3) chilling the carcass
with 2 to 4°C water for 6 to 10 seconds to
reduce the surface temperature to 20°C
before storage in a chilled environment.
Since meat may be contaminated during fur-
ther processing, hot water and steam pas-
teurization can be used to decontaminate
trimmings and cuts. However, meat color can
change during pasteurization, reducing the
desirability of the end product (Maddock,
2004).
Thesteam-vacuummethod was originally
designed to take advantage of both hot water
and steam, in combination with a physical
removal of bacteria and contamination viaSanitizers 185Table 10–4Chemical Sanitizer Applications
Sanitizer Application
Chlorine All food-contact surfaces, spray, CIP, fogging
Iodine All food-contact surfaces, approach as a hand dip
Peracetic acid All food-contact surfaces, CIP, especially cold temperature and carbon
dioxide environments
Acid anionics All food-contact surfaces, spray, combines sanitizing and acid rinse into one
operation
Quaternary All food-contact surfaces, mostly used for environmental control; walls,
ammonium drains, tiles
compounds