Hot water is relatively inexpensive, easily
available, and effective in microbial destruc-
tion as well as having a broad antimicrobial
activity. It is generally noncorrosive and pro-
vides sufficient heat penetration into difficult
to reach areas such as behind gaskets, and in
threads, pores, and cracks.
The use of hot water has limitations since
it is comparatively slow and requires a
lengthy process involving: heat, hold, and
cool down, compared to chemical sanitizing.
Furthermore, it can cause film and scale for-
mation or heat fixing of any remaining soils,
making future cleanup more difficult. Hot
water can shorten equipment life because of
thermal expansion and contraction stress
and cause premature failure. Equipment
must be designed to withstand a temperature
in excess of 82°C and hot water in the system
creates condensation within the plant pro-
duction environment and water heated above
77 °C is hot enough to cause serious burns.
Chemical Sanitizing
This method is accomplished by pumping
an acceptable sanitizer such as the halogens
(usually chlorine or iodine compounds)
through the assembly for at least 1 minute.
This technique requires contact of the sani-
tizer with all of the possible product sur-
faces. Because contact of the sanitizer with
the surface is essential, the application
method in dairy operations is important.
For large-volume, mechanized operations,
the sanitizer can be applied through sanitary
pipelines by circulation, or pumping of a
sanitizing solution through the system.
The appropriate amount of sanitizing solu-
tion is prepared in a container and pumped.
A slight backpressure should be built up in
the system to ensure contact with the upper
inner surface of the pipeline.
Small operations that cannot justify mech-
anization can sanitize by the submersionof
equipment, utensils, and parts in the sanitizer
solution. This process normally involves sub-
mersion for approximately 2 minutes, then
draining and air-drying on a clean surface.
Closed containers, such as tanks and
vats, are easily and effectively sanitized
through fogging. The strength of the sani-
tizing solution should be twice that of the
ordinary use solution and it should be given
at least 5 minutes of exposure.
If a sanitizer is applied through spraying,
all surfaces should be contacted and com-
pletely wetted. As with fogging, the sanitiz-
ing solution strength should be twice that of
the ordinary use solution.
If mechanized sanitizing equipment is
unavailable, large open containers, such as
cheese vats, can be sanitized by brush appli-
cation. All areas should be touched with the
brush. This method has high labor costs.
Sanitized surfaces should not be rinsed
with water; otherwise, equipment and uten-
sils can be recontaminated with aerobic
microorganisms that reduce product stabil-
ity. Furthermore, other recontamination of
the sanitized surfaces should be avoided.
Cheese ripening rooms possess an envi-
ronment that encourages mold growth.
Ozoneis effective in the inactivation of air-
borne molds in this environment, but not
surface molds. Serra et al. (2003) indicated
that it was necessary to wipe the surfaces
with a commercial sanitizer to decrease the
viable mold load on these surfaces.Cleaning Steps
Dairy operations require eight cleaning
steps:- Cover electrical equipment. Covering
material should be polyethylene, or
equivalent. - Remove large debris. This task should
be accomplished during the production
shift and/or prior to prerinsing.
3.Disassemble equipment as required.