shouldbe realisedthat in foodenvironments thereis oftenlittlevalue in tryingto
directlycorrelate surfacecounts to ATPreadings.For a strongcorrelation,the
ratiobetween microbial ATPand fooddebriswouldneedto be constant.Thisis
unlikelyto occurin many foodpremisesand sites,withthe possible exception of
somehandcontact surfaces (Griffithet al., 2000).It is possibleto havefood
Table36.2 Comparisonof microbiologicaland non-microbiologicaltesting
Attribute Microbiological
(cultivation)
ATP ProteinAcceptance Widelyaccepted
by foodindustry
worldwide.
Althoughnot
universally
accepted,it is
widelyacceptedin
the UK and many
othercountries.
Acceptancehas
increasedrapidly
since1995.Generallyless well
acceptedthanATP
but morerecently
developed
technique.Method/principle
testing
Microorganisms
derivedfrom
surfacegrowand
multiply.
Laboratory
facilities,or at
minimum,portable
incubationand safe
disposalsystems
required.ATPderivedfrom
microorganisms
and fooddebris
convertedinto
lightand detected
usinga
luminometer.No
laboratoryfacilities
needed.Proteinfrom
surfacefooddebris
transferredontoa
swabor equivalent.
Proteindetectedby
a colorimetric
reactionand
comparedwith
colourstandards.
No instrumentation
or laboratory
facilitiesrequired.Timefor results 18±48hours. 2 minutes. 5±10minutes.
Reproducibilityfor
raw milk
contaminatedsurface
CV 84±300%. CV 9±79%. Not applicable.Approximaterunning
costs
60±100pence
(in-house).95±155pence. 95±145pence.Capitalcosts Variablebut
incubator£130±
2000
Autoclave£600±
10,000.
Luminometer
£900±2500.Optional
colorimeter
availablefor some
tests.Staffrequirements Somelevelof
microbiological
training.
Brieftrainingin
test protocol.No
specialised
knowledge
required.Brieftrainingin
test protocol.No
specialised
knowledge
required.Improvingsurfacesamplingand detection of contamination 595