ListeriafromZone 2 sitesfirst,beforeconsiderationof Zone 1. Failureto do so
is onlylikely to lead to rapidrecontaminationof Zone1 surfaces.
Zone3 includes floors,walls, etc. in areasmoredistantfromZone1, and
comprises the leastcriticalfoodhandlingareaswhere samplingfrequency may
be at its lowestand environmentalcontamination at its highest, e.g. whereraw
products are received. Thisis relative, i.e. in relation to Zone1, and is not an
excuse for poorcleaning,or not testing. It is a recognition,basedon risk,that
less stringentsamplingis needed.
However, all three zonesneedto be consideredin terms of productflowand
peoplemovement. Depending on where and how it is used,the degreeof
separation of highfromlow risk and its potential to spread bacteria,cleaning
equipment couldbe consideredas Zone2 or 3. The use of contaminatedcleaning
equipment is one of the mainreasons for failure to cleaneffectively (see Table
36.7)and can spread pathogensfromlow-to high-riskareas.Ideallyeacharea
and zoneshould havehygienicallydesignedcolour codedequipment, which
shouldnot be usedin otherareas.Essential also is that this equipmentis stored
cleananddry, or if used on a semi-continuous basis,frequentlycleanedand
storedin freshdisinfectantsolutionmonitoredfor concentrationlevels. Care
shouldalsobe taken,especiallyinListeriacontrolprogrammes, withshoes/
boots,tracks, etc. ± theseneedto be cleanedproperly as theycan spread
organismsaround premises (Tomkinet al., 1999).
Thistypeof framework fits into the increasing use of cleaning and cross-
contaminationaudits.Cleaning audits (internalor external) should be conducted
independently and assess both the quality and adequacy of the cleaning
programme and the levelof compliance withit. Newpersonaldigitalassistants
(PDA), palm-held auditing toolswithappropriate software, are available (http://
http://www.foodsystemsaudit.co.uk),,) which simplify the whole process and can
incorporate datafrommicrobiological or rapidtesting. Oneadvantage of the
PDAsis that draftreportscan be produced, if necessary,beforethe auditor
leaves the areas/premises being audited. Other advantagesinclude greater
consistency,overalltimesavingsand greater usability of datafor analysing
trendsand designing correctivestrategies.Thesebecome evenmorepowerful if
combined withcross-contamination audits, whichare broaderin scope,and used
to assess the overallrisk or potential for cross-contamination.The latterassess
morethanjust cleaning,and includepersonalhygiene, facilities available,e.g.
hand-washing and drying, traffic and personnel flow. Monitoring surface
cleanlinessis not without costs but theseneedto be considered in relationto the
costsassociated withfailingto monitor(see Fig. 36.11).
36.4.3 Usingthe results
Giventhe cost of cleaningand the expenditurein time, effortand money that
somecompanies put into surface samplingit is surprisingthat moreuse is often
not madeof the results.It has beensaid `if it wasn't recordedit did not happen'
and documentedresultsfrommicrobiological and non-microbiological sampling
Improvingsurfacesamplingand detection of contamination 613