transferredinto a neutralisingsolutionand surviving microorganismsenume-
rated.As for otherEuropeantestsproducedby CEN/TC216, additionalmicro-
organisms,contacttimeand temperature can be usedto reflectin-useconditions.
An alternative to inanimate surfaces are the hand-washingtests that have
beendevelopedfor determining the antimicrobial efficacyof antiseptics.There
are severalantiseptictest protocols available,(e.g.glove-juice, sterile bag,
washingand rinsing), which differ in theirbasic assessment methodology
(Anon,1997;Sattarand Ansari,2002).In Europethe maintestingprotocols
werethe Viennaand the Birminghammodels(Ayliffeet al., 1978;Rotter and
Koller, 1991).CEN/TC216releasedtwo antiseptictests,the Hygienic Hand-
wash test (EN1499)and the Hygienic Handrub(EN1500).Basically,in the
Hygienic Hand-washtest (CEN, 1997b),fingersand thumbtips are immersed in
a non-pathogenicsuspensionofEscherichia coli(NCTC10538) and air dried for
3 min.The antiseptic formulation is thenappliedand handsrubbedaccordingto
a standardisedhand-washprocedure. Survivingbacteriaare thenrecovered and
enumeratedaftera neutralisationstep.
Othersurfacetest protocolsagainstspecificmicroorganisms suchas myco-
bacteria (Section38.4.3), sporesandLegionellahavebeendescribed. These
microorganisms,particularlymycobacteria and spores provide extrachallenges
for the biocidal product and the test methodology;they are moredifficult to grow
in the laboratorythan standard vegetative cellsand they are particularly resistant
to biocidalchallenges.As a result, morestringent regimens(e.g.high-level
disinfectants) are neededto ensurethat specificequipment (e.g.endoscopes)
have been appropriately chemically sterilised. Standardised practical tests
simulatingconditionsin situ(i.e. medical instrumentdisinfectants ± sporicidal/
mycobactericidal/virucidaltests) are beingdeveloped(Section38.4.3).
Capacitytest
Capacitytestssuchas the Kelsey-Sykes test (e.g.British Standard BS 6905;BSI,
1987)differsomewhatfromthe suspensiontest in that the biocideis challenged
withseveraladditionsof a bacterialsuspension.Aftereachaddition,the number
of survivors is measured. Suchrepetitiveadditionsallowthe determinationof
when the biocide activity (i.e. capacity) has beendrained.Capacitytestsattempt
to simulate practicalapplicationsin the field(i.e. real-life conditions)and in
some instances are usedto confirmthe efficacyof an `in use'dilution.
38.4.3 Othertestingmethodologies
Mycobacteria are generallyconsidered more resistantthanothervegetative
microorganismsto disinfection(Lambert, 2002)and therefore haveto be tested
separately(Holah,2003).Mostmycobacteria are slow-growing microorganisms
and havea tendencyto formclumps(as a result of theirhighhydrophobicity),
whichcontributeto theirresistanceprofile(Lambert, 2002).The most important
species isM. tuberculosisand oftentestshave beenlabelledtuberculocidaltests.
However,M. tuberculosisis particularly slowgrowing and is an important
660 Handbookof hygiene controlin the foodindustry