of decompositionof ozonein wateris affectedby the concentration and typeof
organic solutes. Compounds mayinitiateozonedecomposition(e.g.glycoxylic
acid),promote decomposition(e.g.formicacid, primary alcohols, benzeze and
humicacid) or inhibit decomposition (e.g.tert-butylalcohol, bicarbonate).
Decompositionis also morerapidat alkalinepH values (Hoigneand Bader1976).
For ozonedispersalin air, use of ventilation can rapidlyreducethe residual
concentration(Masaokaet al.1982).If usingozonegas as a terminal sanitizerin
an unoccupiedspace,an evaluationmustbe made of the rate of decomposition
to ensure that there is no risk to the health of returning personnel.
31.6 Futurepotential
The low efficacyof ozonein certain circumstances has led to researchinto the
use of ozonein combination withothertreatments. Theseincludeheat treatment,
negative air ions and natural oils.It has beenshown that theremaybe synergy
between ozoneand theseothertreatments,whichwouldleadto an enhanced
effect,comparedto the individualtreatments.
31.7 Conclusion
Ozonehas been proved to be an effective antimicrobialfor a number of
applications.It is not, however, a cure-all and thereare significanthealthand
safetyimplicationsand detrimentaleffects to foodand the environment. It is
also difficultto adviseas to the exactconcentrationof ozone,eithergaseous or
aqueous, needed for a certain applicationowing to manyfactors suchas the
amount of organic material present, the desired effect and the operating
conditions of the system. It does,however, have the potential to be usedas a
terminalsanitizerfor foodcontactequipment and the environment,providedthat
personnelcan be excludedduring its application and degradation. Levels of
ozone of 2 ppm have been shown to be effective against a range of
microorganismsin the laboratory (aerosolizedand surface attached)and in
industry. Ozonated watercan also be usedfor decontaminationof surfaces and
equipment, and has the potentialfor use in cleaning-in-place systems.It also has
fewerhealthand safetyconsiderationsthanthe use of ozonegas. A thorough
investigation must,however, precedeany use of ozoneor ozonated waterto
ensureproduct, equipment and personnelsafety.
31.8 Sources of furtherinformationand advice
InternationalOzoneAssociation,IOA-EA3G Secretariat,Ba√t. ESIP- 40 av. du
Recteur Pineau, 86022 POITIERScedex, France (http://www.ioa-ea3g.org/
homepage.asp).
Ozone decontamination in hygiene management 513