Food Safety Magazine, February/March 2012

MICROBIOLOGYOPRPs as a Control for Product VectorsSince the control of significant product vectors is especiallycritical to product safety, these controls could be described asOPRPs. An OPRP requires the establishment of operating limits(or control limits), monitoring activities, corrective actionsfor when a control limit is not met, verification activities andrecord-keeping procedures.Table 3 describes the controls associated with the theoreticalmilk spraying nozzle removal and reinsertion procedure describedin Table 2. The hazard is that Salmonella could be takeninto the dryer on the nozzle and supporting wand, and via theair surrounding the top of the dryer. The nozzle and wandcould be cross-contaminated from the operative’s hands andclothing and from the tools used. Control measures could includechanging into clean clothing at the point of nozzle removaland reinsertion, using dedicated tools and cleaningequipment, decontaminating wands and nozzles and all surfacestouched prior to reinsertion and tamperproof tagging ofthe wands so that they cannot be unintentionally removed. Bymicrobiologically filtering environmental air surrounding thedryer, contamination from the air at routine dryer interventionswould be controlled.ATP testing prior to entry could apply an operating limit toan assessment of the cleanliness of the wands, nozzles andProcess step or process activityObservationLikely hazardContamination event vector(s)Product vector risk analysis without controlsPotential presence of hazard on vector: LHMFrequency of event: LMHSeverity of hazard: LMHRisk scoreSubsequent control step?Current or intended vector controlsProduct vector risk analysis with controlsPotential presence on vector: LHMFrequency of vector: LMHSeverity of hazard: LMHMilk spray dryingGuillotines or spray covers areinserted into the dryer toseparate the dryer from the baghouse during CIP cleaningof the dryerSalmonellaContamination on the reverseside of the guillotine enteringthe dryer on guillotineremoval after CIPMediumHighHigh18Prior to start-up, the dryersurfaces are subjected to hot airat up to 205 °C/400 °F for 2 hoursNot necessary due to subsequentcontrol steptools, and verification of cleanliness could be periodically undertakenby microbiological sampling. During the nozzle removalprocedure, observations could be made to ensure theprocedure was being done correctly and that there were no extrinsicfactors that could act as additional cross-contaminationvectors. Records would be kept of all interventions into thedryer, whether removal and reinstallation procedures had beencorrectly followed, ATP and microbiological counts and tamperprooftag numbers. Corrective actions would review thetraining of the staff against removal and reinstallation proceduresand the effectiveness and validation of the tools andcleaning equipment decontamination programs.In the same manner as CCP records, the records of anOPRP should be incorporated into a food safety plan to ensureall essential conditions were met during the manufacture of aproduct. If a deviation in an OPRP were to occur, then the affectedproduct should be placed on hold while a cross-functionalteam is assembled to review the associated risk and makea decision on product disposition.The management strategy described above for OPRPs is essentiallythe same as for CCPs as defined under HACCP. Sothen what is the difference between a CCP and an OPRP?CCPs are generally described for specific steps in the manufacturingprocess to eliminate or reduce a significant hazard to anMilk spray dryingApproximately once per shift, milkinjectors are removed from thedryer, cleaned and reinstalledSalmonellaDryer nozzles touch hands,clothing and tools prior to entryRisk score99Table 2: Theoretical observational record of potential cross-contamination vectors associated with two spray dryer intervention procedures.HighHighHigh27NoneGloves are worn and nozzlesand tools are decontaminatedwith alcohol prior to dryer entryLowHighHighMilk spray dryingApproximately once per shift, milkinjectors are removed from thedryer, cleaned and reinstalledSalmonellaAir can enter the dryer duringthe nozzle removal andinstallation processLowHighHigh9NoneNoneLowHighHigh60 F O O D S A F E T Y M A G A Z I N E