Handbook of Hygiene Control in the Food Industry

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36.1.3 Monitoringcleaning
Cleaning, as statedearlier,is the removalof soil and the processmay also reduce
the number of microorganismspresent. Disinfection is specifically used to
furtherreduce the numberof microorganismspresentand can be achievedusing
heator chemicals.Bothcleaningand disinfectioncan be monitored, although
readersare reminded that disinfection is muchmoredifficult and less likelyto
be achievedif priorcleaningis inappropriatelyperformed.
Figure36.3indicatesthe possible consequences and combinations of surface
conditions aftercleaning.The reductionin organic residues ensuresremovalof
fooddebris,allergens,etc., helpsreduce the number of microorganisms,as well
as preparing the surfacefor any furtherdisinfection.A low residual microbial
surfacecountreducesthe chancesof foodspoilage and possibly foodborne
disease. Thepresenceor absence of residual moistureis alsoimportant in
helpingto preventcross-contamination bothby reducingmicrobial growthand
survivaland reducingpotentialtransferrates.Transfer ratescan vary,fromless
than1% to nearly100%depending uponthe surfaces, and are greatlyincreased
in the presenceof moisture(Harrisonet al., 2003). However, dryingneedsto be
performed in a waythat will not recontaminatethe surface.
Figure36.4outlines the variousmicrobiologicaland non-microbiological
methodsthat could be usedto assess the efficacyof cleaning and/ordisinfection.
Microbiologicalmethodsprovide onlyan indication of the numbers of residual
surface organisms. Non-microbiological methods primarily assess residual
organic surfacedebris, althoughsome,suchas ATP,may,by virtueof its ability
to assess microbialATP, alsodetect microbial contamination. However,it


Fig. 36.3 Possiblecombinationsof surfaceconditionaftercleaning:*desirablesurface
condition,dry and free frommicroorganismsand residualorganicsoil.


Improvingsurfacesamplingand detection of contamination 593
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