(HACCP)study. For low-risk products, the first two barriers onlyare likelyto be
required.For high-risk products, the use of the third barrieris requiredfor
microbiological control.The fourthbarrier is necessaryfor asepticproductsin
whichthe eliminationof external contaminationis required, though somefully
cooked, ready-to-eat productswithextended shelf-life maybenefit fromthe
additional controls this barrier affords. Although not absolutely necessary
because of hazardcontrol,manufacturersmaychooseto processfoodin higher
hygiene zonesfor otherreasons.Thismaybe because of locallegislation, or
theymaybelievethat in the nearfuture theirproduct rangewill includehigher-
riskproductsand it makes financial senseto develop the infrastructure to
produce suchproductsat an earlierstage,or simplybecause theybelieveit will
facilitatebrandprotection.
8.2 Barrier1: Site
Attentionto the design, construction and maintenance of the site, fromthe outer
fence and the areaup to the factorywall, providesan opportunity to set up the
first of a seriesof barriersto protectproductionoperations fromcontamination.
This levelprovidesbarriersagainstenvironmentalconditions,e.g. prevailing
windand surfacewaterrun-off, unwantedaccess by peopleand avoidanceof
pest harbourageareas.
At the site level,a number of stepscan be taken,includingthe following:
∑ The site shouldbe welldefinedand/orfenced to preventunauthorised public
access and the entranceof domestic/wildanimals,etc.
∑ Measurescan be put in placeto maintain site securityincluding the use of
gate houses, security patrols and maintenance schedules for barrierfencingor
other protection measures.
∑ The factory buildingmayoftenbe placed on the highest pointof the site to
reduce the chance of groundlevelcontamination fromflooding.
∑ Well-plannedand properlymaintained landscaping of the groundscan assist
in the control of rodents, insectsand birdsby reducing foodsupplies and
breedingand harbouragesites.In addition,goodlandscapingof sitescan
reduce the amount of dustblowninto the factory.
∑ Open waterways can attract birds, insects, vermin, etc., and shouldbe
enclosedin culverts if possible.
∑ Processes likely to createmicrobial or dustaerosols, e.g. effluenttreatment
plants, waste disposal unitsor any preliminarycleaning operations,should be
sitedsuchthat prevailing windsdo not blowthemdirectlyinto manufacturing
areas.
∑ An area of at least3 m immediatelyadjacentto buildingsshould be keptfree
of vegetation and covered witha deeplayerof gravel,stones,pavingor
roadway, etc. Thispracticehelps maintaincontrol of the fabric of the factory
building.
150 Handbookof hygiene controlin the foodindustry