Plant Cleaning and Sanitation 291alent alternative procedures to 82 ° C dipping
to be used (Eustace et al. 2007 ; USDA 2004 ).
A 15 - second immersion time in water at
82 ° C or warm water (approximately 50 ° C)
containing quaternary ammonium com-
pounds was suggested as being effective in
reducing bacterial numbers by about
3 log CFU/cm^2 (Taormina and Dorsa 2007 ).
A recent study (Goulter et al. 2008 ) dem-
onstrated that dipping knives in water for
shorter times at higher temperatures, for
example, 82 ° C for 20 seconds, or for longer
times at lower temperatures (70 ° C for 45 s),
can produce equivalent inactivation of the
tested bacteria (more than 5 - log reduction
against Escherichia coli and Listeria mono-
cytogenes ). Pre - rinsing knives at 40 ° C
increased the performance of the subsequent
dipping step. As such, a pre - rinse should be
implemented where possible to increase the
general status of knives in those meat -
processing operations in which it is
recommended.
Hot - water sanitation is easy to apply,
readily available, effective for a broad
range of microorganisms, and noncorrosive.
However, it can contribute to the formation
of biofi lms.
In meat - processing plants, chemical sani-
tizers are preferred; concentration, exposure
time, temperature, pH, water hardness,
surface cleanliness, and bacterial attachment
are the most important factors affecting sani-
tizer activity (Marriott 1999 ). Important
properties of a sanitizer are: ability to provide
rapid antimicrobial activity against a range
of organisms; easy availability, inexpensive
cost, and readiness to use; stability and resis-
tance to the presence of organic matter, deter-
gent, and soap residues; ability to work in a
wide range of pH, water hardness, and tem-
peratures; lack of toxicity to humans; and
non corrosive and water - soluble action
(Guthrie 1988 ).
The following table (Table 15.1 ) provides
information about appropriate chemicals
for sanitizing in meat - processing facilities.Step D: Rinse with Water
Complete removal of cleaning agents is
important, since residues may completely
inhibit the effect of the sanitizer that is
applied next. All equipment should be
rinsed within 20 to 25 minutes after cleaning
compound application, using the same
pattern as the pre - rinse and detergent applica-
tion. A common procedure may consist in the
use of water at 45 ° – 55 ° C with a pressure
of 30 bar and 20 L water per minute. After
this step, a fi rst inspection of the equipment
surfaces, even touching as necessary, is
recommended.
Step E: Application of
Sanitizer (Disinfection)
Cleaning reduces a substantial amount of
microorganisms but it does not have the
potential to eliminate all surface contamina-
tion. Persistent microorganisms will continue
to grow in number by using the remaining
protein as nutrients, and they pose a further
risk to the foods to be processed. Following
the initial rinse that removes gross soil, deter-
gent application, mechanical scrubbing,
and a fi nal wash to remove detergent, sanitiz-
ers (or “ disinfectants ” ) are applied to com-
plete the procedure. This step is called
“ disinfection ” and can be accomplished with
physical treatments such as hot water, steam,
or UV irradiation, or by means of chemical
compounds.
Hot - water sanitizing is commonly used
where immersing the contact surfaces is
practical (e.g., small parts, utensils). Both
time and temperature are important.
Depending upon the application, sanitation
may be achieved by the immersion of parts
or utensils in 77 ° C to 85 ° C water for 5
minutes to 45 seconds, respectively.
For example, many countries still require
the sanitation of knives used in meat process-
ing by brief immersion in water at no less
than 82 ° C. However, many current interna-
tional regulations allow science - based equiv-