surfaces.Rough-surfacedmachine parts,handtools,and utensils mayharbor
foodsoil and shieldharmful microorganismsagainstthe rigorof the applied
cleaningprocess.In addition to stainless steel,plastic, and rubber, a host of other
polymers are usedwidelyfor constructing valvecomponents, pumppartsand
other components usedin a modern foodprocessingoperations.The polymers
must be reviewed on a caseby casebasisto determine theircompatibilitywith
chemicalsand temperaturesusedin the cleaning process.
Temperature and temperature control
The temperature of the washing solution is extremely important in achievingthe
cleaningobjective.Mostcleaningcompoundsare designedto be active overa
relativelynarrowrangeof temperatures. Exceeding the limitsof that range,on
eitherthe highor the low side,mayimpairthe effectiveness of the cleaning
process. Thereare a host of otheradverse effects that might be expected to occur
as a result of usinginappropriate washing temperatures.For example,elevated
temperatures may adversely affect the detergency of a selected cleaning
compoundby alteringits foam-producingcapacity as a resultof changingthe
compound's ratioof hydrophobic/hydrophilic balance.Inappropriate washing
temperaturesmay also impactthe physical or chemical stabilityof the targetsoil
and result in the formation of precipitatesor films.Recall that manyproteins are
denaturedat temperatures above185 ÎF (85 ÎC) causingthemto formdifficult to
clean films. Not onlyis it importantto selectthe correctwash cycletemperature,
it is imperativethat the selectedtemperatureis controlled and monitoredduring
the entirety of the specified washcycle.
Exposuretime
Determining the duration of the washcycleor the lengthof timerequired to
achieve the complete removal of the undesirablesoilsis an essentialfor setting
an effective process.It is also complex.Exposuretimemust considersoil type,
quantity, and its physicalform.Waterhardness,detergent type,and washing
temperature will also impact setting of exposure time. Another major
considerationin this regardhas to do withthe applicationof forceduringthe
cleaningprocess. A static, force-free process,will typicallyrequirea greater
exposure timethanwill a force-aided cleaning process.
Force or agitation
The applied mechanical energy in the form of shear forces created by
turbulence, scrubbing, acoustic action or other forms of agitation is an
importantelement of a COPcleaningprocess. The systematic applicationof
force duringcleaning will greatlyexpedite the process.For example, the use of
power ultrasoundduringcleaninghas beenshownto radicallyreducecleaning
cycle time.It is morecommonplace, withCOPcleaning,to employagitation
during the wash cycle.Agitation withina standard COPtankusuallyresults
fromthe use of a high-speed recirculation pumpand speciallydesigneddelivery
nozzles.
456 Handbookof hygiene controlin the foodindustry