propertiesand spectrum of activity(Russell, 2001)(Table38.1).Selectinga
biocidefor a specificapplicationdepends not onlyon the characteristic of the
agent(e.g.toxicity, corrosiveness, spectrumof activity) but also usagecondi-
tions(e.g.risk associatedwitha surface, equipment; typesof microorganisms
expected, soiling,levelof microbial contamination)(Table 38.2).
38.2.1 Biocides, activity and usage
Biocideshavebeenusedfor centuries,originallyfor the preservationof food-
stuffs and water, and then for the control of infection (mainly through
antisepsis).A largenumberof currentantimicrobialagentshavebeensynthe-
sisedmorerecently(Fraise, 2004a). The mainapplicationsof biocides are in the
food,waterand pharmaceuticalindustryand in the healthcareenvironment,
althoughsomebiocidesare usedin applicationsin specialised areas,for example
the preservationof petroleumproducts, textileand leather,paint,woodand
generally in the constructionindustry. Morerecently,productscontaininglow
concentrationsof biocideshaveappeared withan increasingfrequency in the
homeenvironment (Levy,2001),mainly as a result of a betterpublicunder-
standing of hygienebut also fromincreased commercialpressure.
Whereasdisinfectant'is a term usedmainly in the healthcare environment (but also increasinglyusedin the domiciliary environment),sanitiser'is usedin
Table38.2 Maindesirablecharacteristicsof disinfectantsand sanitisers
In relationto antimicrobialactivity
Broadspectrumactivityincludingactivityagainstbacteria,fungi,viruses
Rapidantimicrobialactivity
Retainstability(product)and antimicrobialefficacyovera widerangeof pH
Retainstability(product)and antimicrobialefficacyovera widerangeof temperature
Retainactivityin the presenceof organicloadand hardwater
Retainactivityupondilution
Residualactivity*
In relationwithsafety
No or low toxicity
Degradablein the environment
In relationwithformulationand usage
No or low corrosiveness
Non-staining
No odour
Goodwettingand detergency
Easilycombinedwithliquidor powder
Compatiblewithotherchemicals(e.g.surfactants)
Cost-effective
- Residualactivity.The presenceof remaininglow concentration(belowthe minimuminhibitory
concentration, MIC)of a biocideon a surfaceis the subjectof muchdebatewithcurrentevidenceon
emergingmicrobialresistanceto biocides.
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