discuss standard protocolsfor disinfectants and sanitisers,theirlimitationand
possible developments.
38.2 Types of biocidal products
To understandthe designand the limitationof antimicrobial test protocols,an
understanding of non-antibiotic antimicrobialagents(i.e. chemical biocides)is
important.Chemicalbiocides are definedas agents withdisinfectant, antiseptic
or preservative activity. Biocides are verydiversein theirchemical structure,
Table38.1 Typesand propertiesof antimicrobialbiocides
Biocides Factorsaffecting Typicalusage
activity
pH Soiling
Aldehydes
Glutaraldehyde,ortho- >7 ˇ Preservation(e.g.cosmetics),
phthalaldehyde,formaldehyde sterilisationmedicalequipment,
fumigation
Peroxides
Hydrogenperoxide,peraceticacid <7 ˇ/á Surfacedisinfection,
sanitisation,sterilisationof
medicalequipment,antisepsis
Halogenreleasingagents
Sodiumhypochlorite,chlorine, <7 á Surfacedisinfection,water
iodine disinfection,sanitisation,
antisepsis
Biguanides
Chlorhexidine,alexidine,PHMB >7 á Preservation,antisepsis,surface
disinfection
QACs >7 á Preservation;antisepsisand
surfacedisinfection,sanitisation
Phenolics
Bisphenols,halophenols <7 á/ˇ Antisepsisand surface
disinfection
Alcohols á Antisepsisand surface
disinfection(oftenusedin
combination)
Organicacids <7 Preservation(sanitisationwhen
usedin combination)
Anionicsurfactants,sodium <7 Sanitisationwhenusedin
laurylsulphate combination
Amphotericagents,betaine, NA ˇ
dodecyl- -alanine,
dodecyl-di-glycine
PHMB,polyhexamethylenebiguanide;QACs,quaternaryammonium compounds.
642 Handbookof hygiene controlin the foodindustry