Exploitationof the bioaerosol result is usually achievedby analysingthe
trends and changesin eachsamplingplaceresults. Careful analysis of long-term
results can highlight contamination levelsof generalor certain contaminants that
havecaused problems in production.Comparing new resultswithold results will
showwhethersomething abnormal is happening in the processat the moment.In
addition the resultsnormally showthe seasonalvariationsthat should not be
mixedwithintrinsic process or process environment createdchanges causedby
potential contamination. The seasonal variations, however, should also be
controlledso that theydo not present a risk for production or employees.A
functional,sensitive and regularbioaerosol monitoringsystem describesthe
process's generalhygienic situation and productionpracticesas wellas the
behaviour of ventilationand pressuredifferences.
37.8 Future trends
The foodindustry is followingthe pharmaceutical and medical industriesby
recognizingthat microbialmonitoringof air is a must in standard quality
control practices. However, in addition to the general contamination power, air
can be the majorcontaminant source of products. There is a published example
showing that air has beenconfirmedas the maincontaminationsource in the
production of cheese (Kure et al., 2004b). This kind of example and
informationwill probably become more commonas resourcesare directedon
the monitoring and study of air quality and contamination effects of air in the
foodindustry.
In additionto the methodsand techniques mentioned in this chapter, the
development of real-time continuous monitoring of airborne microbes is
importantfor the foodindustry.Given the abilityto respond quicklyto the
findingsof continuous monitoring,this kindof systemwouldprovidea tool to
detect abnormalities, problems and trendsin processes that are not alwaysfound
withnormalshort-termperiodicsampling. Continuousmonitoringwouldalso
offer informationon sourcesand spreadof contamination. UVAPS (Ultraviolet
Aerodynamic ParticleSize Spectrometer) is the firstcommercialreal-time
aerosol sampler that monitors viablebioaerosols. It is equippedwitha pulsed
laser that measures aerodynamicsize,scatteredlightintensity and fluorescence
of airborne particles withina sizerangeof 0.5 to 15lm. It has,however,
limitationsin its sensitivityto the type of airborne bacteria and especially
bacterialspores;in addition,the growth phaseand environmentalstresslevelof
bacteria reducethe sensitivitylevel.The countingefficiency of the fluorescent
particles dependon particleconcentration,withthe upperlimitof detection
being approximately 6 x 10^7 particles/m^3 and the identification of contaminating
species is not possible (Agranovskiet al., 2003a,2003b). Neverthelessthis kind
of technique will improve and theirbenefitsshouldbe understoodand exploited
as theydevelopto functionaland practicalapplications.
636 Handbookof hygiene controlin the foodindustry