the field(Changet al., 2001).Morerecently,the roughness peakheight, also
called mean levelling depth,Rpm, whichis the mean valueof the levelling
depths of five consecutive sampling lengths,becamethe preferred roughness
parameterof the Health and SafetyExecutive (Anon,1999)and of Changand
Matz (2000), citedby Changet al.(2001).
9.3.2 Hygiene
As writtenin the introductionparagraph,flooringmaterials maybe a reservoir
of microorganisms.The pathogenListeriamonocytogenes, whichis frequently
found on floors, can even become persistent in food industry premises
(Giovannacciet al., 1999;Miettinenet al., 1999;Chasseignauxet al.2001).
Lawrenceand Gilmour(1995), usingRAPD(randomamplifiedpolymorphic
DNA) and multilocusenzymeelectrophoresis as typingmethods, foundtwo
coexistingL. monocytogenestypeswidespreadon foodcontact surfaces, floors
and drainsduring an extendedperiod.Thesebacterialtypeswerealso foundin
the cookedpoultryproductsfor at leastone year. Thishighlightsthe potential
for persistentstrainsto cross-contaminate processed foods.
Regulation
In the European Directive 93/43/EEC,it is stipulatedthat
floor surfaces must be maintainedin a soundconditionand theymust
be easyto cleanand,where necessary, disinfect. Thiswill requirethe
use of impervious,non absorbent,washable and non-toxicmaterials and
requirea smoothsurfaceup to a height appropriate for operationsunless
businessoperators can satisfy the competentauthoritythat other
materials usedare appropriate.Europeanregulationswill replacethe EuropeanDirective93/43/EECand many
sector-specificDirectiveson foodsof animalorigin.Theywill be applicableas
of 1 January 2006.The text concerningfloor in the 852/2004 regulation is very
similar:
floor surfaces are to be maintained in a soundcondition and theymust
be easyto cleanand,where necessary, disinfect. Thiswill requirethe
use of impervious,non-absorbent,washable and non-toxicmaterials
unless foodbusinessoperators can satisfy the competentauthoritythat
other materials usedare appropriate.Whereappropriate, floorsare to
allowadequate surfacedrainage.Surface texture
The studyby Mettlerand Carpentier(1999)on the impactof surface texture on
the hygienic propertiesof flooring materials showed thatgas bubble holes,
whichare frequently foundon resin-basedflooring materials, are not cleanable
(Fig. 9.2).Indeeda smoothpolyurethane-basedflooring material containing
174 Handbookof hygiene controlin the foodindustry