Download Disinfectant #9: Peracetic acid: Weak acid, Strong Disinfectant

Disinfectant#9:Peraceticacid:Weakacid,StrongDisinfectant?
Peraceticacid(PAA)wasfirstregisteredasadisinfectantin1985bytheEPA.PAAisproducedby
combiningaceticacid(vinegar)andhydrogenperoxide.Theresultisaperoxideversionofaceticacid
(vinegar)thathasaverydistinctiveandapungentvinegarysmell.Itisaweakacidcomparedtoacetic
acidbutcanbehighlycorrosiveifnotusedattheappropriatedilutions.Peraceticacidisaversatile
chemicalthatcanbeusedinavarietyofapplicationswithitsmainuseasadisinfectantproductinfood
andbeverageprocessing/producingplantsduetothefactthatitleavesnoharmfulresiduesand
decomposesintoharmlessbyproducts.
ThisishowwewouldratePeraceticaciddisinfectantsbasedonthekeydecisionmakingcriteria:(see
below)
PeraceticAcidDisinfectantReportCard
Subject
Grade
Speedof
Disinfection
B
to
C
Spectrumof
Kill
A
to
C
Cleaning
Effectiveness
SafetyProfile
C
to
D
B
to
C
Environmental
Profile
A
to
B
Cost
Effectiveness
B
Comments
Ata5minutecontacttimeforkillingbacteriaandviruses,peracetic
acidisfairlyrapidinkilling.Howeveritcarriesa30minutesporicidal
contacttime,whichisunrealisticunlessusedforsoakingapplications.
Certaintemperatures,pH,andconcentrationsaffecttheefficacyof
peraceticacid.
At3000ppm,peraceticacidcankillallmicrobiallifewhereasat10
ppm,itonlykillsbacteria.
Peraceticacidhaspoorcleaningcapabilities
Peraceticacidhasasafeoraltoxicity,however,itissensitizingtothe
respiratorytractandirritatingtoskinandtheeyes
Peraceticacidreadilydecomposesanditsprimaryandsecondary
productsarealldeemednon-harmfultotheenvironment.
Peraceticacidisreadilyavailablefromvariousmanufacturersandcan
befoundinbothconcentratedandready-to-useformats.
Asacleaner,peraceticperformspoorlyasitlacksdetergencyproperties.Asalludedtoin
previousblogs,youmaywonderwhetherincreasingtheconcentrationofthisacidwouldbenefitits
cleaning.Theanswerinshortis:No.Ahigherconcentrationwouldnotincreaseitscleaningabilitiesand
infactwouldleadtoanincreaseincorrosiveness.
Asagermicide,peraceticacidshowsfairlystrongefficacyagainstabroadspectrumof
pathogens.Likemanydisinfectants,thetemperature,pHandconcentrationallplayasignificantrolein
determiningtheantimicrobialproperties.Itisbactericidalat10ppm,fungicidalat30ppmandvirucidal
at400ppmina5minutecontacttime.Furthermore,itissporicidalatconcentrationsof3000ppm.Itis
moreeffectiveatslightlyhighertemperaturesanditsgermicidalactivityincreasesathigherpHranges.
CombinationsofPAAandhydrogenperoxidefurtherboosttheefficacyprofile,asthisblendcanprevent
theformationofbiofilmsonhardsurfaces.ThemethodbywhichPAAattackspathogensisthroughthe
reactionwiththecellularwalls.Thisleadstobreakdownofcellmembranesandcellulardeathdueto
cellcontentleakage.AnissueregardingPAAusageisitsstability.Inthepresenceofwater,itbreaks
downquickly.Thiswouldhaveadirectaffectontheviabilityoftheproductovertime.
Peraceticacid’ssafetyprofilecanalsobecloselycorrelatedtoitsconcentration.Thehigherthe
concentration,theworsethesafetyprofileis.Forexample,aninusesolutionofPAAof5%hasrelatively
loworaltoxicityatthisdilution.However,respiratoryissues,includingoccupationalasthma
developmentassociatedwithPAAhavebeenreported.Further,itcanstronglysensitizerespiratory
organsandcausemucusmembraneinflammation.Furthermoreitisimportanttobewearyofskinand
eyeexposureasitcancauseirritation.Overall,peraceticacidpropercareneedstobetakeninitsuse.
Theenvironmentalprofileofperaceticacidonceagaindependsontheconcentrations
encountered.Athighconcentrations,itcanbetoxic.However,inuseconcentrationsdonotposemajor
threatstotheenvironment.Furthermore,PAAisareadilydecomposablesubstanceandbreaksdownto
productsthatarenotconsideredharmfultotheenvironment.