Ozone
Ozone,or more properly tri-atomic oxygen(O 3 ), has beeninvestigated and
shownto be an effective methodfor sanitizingpre-cleaned nonporous surfaces.
Testingconducted by Air Liquideand Del Industries Inc.,(witnessed and
reported by the NationalSanitation Foundation, July2001) (Boisrobert,2002)
showa 5 log reductioninE. coliwithin30 s of exposure to ozoneat concen-
trationsthat ranged from2.1 to 4.2 ppm.Ozoneactivityhas also beenreported,
by these sameworkers (Boisrobert, 2002),againstStaph.aureus,Salmonella
choleraesuis,Listeria,Camplyobacter,Aspergillus, and otherfungi. Tri-atomic
oxygen is produced by reacting two oxygen atoms (O) with twooxygen
molecules (O 2 ) to formthe veryunstable tri-atomicspecies:
2Oá2O 2 ˇ!2O 3The germicidaleffectof ozoneis derivedby wayof oxidation (see Fig. 28.1).
Specificallythe compoundattacksand disrupts bacterialcell walls and also
oxidizes DNA. Ozone is partially soluble in water(more so than oxygen)and its
germicidalactivity is not adverselyaffectedby hard water.
Fig. 28.1 Antimicrobialstrengthcomparison(afterDel Ozone,2004).Improvingcleaning-out-of-place(COP) 461