Anionic wettingagentsare essentiallypH neutral and usuallycompatible
withacidor alkalinecleaners and certain classesof soap.Theyfrequently
provide a synergistic effectwhen combinedwithsodium sulfate,phosphates,
sodium carboxymethylcellulose, and some natural gums (Elliot, 1980;
Katsuyama, 1980). Thehundreds of compounds withthis designation are
typically placedinto five categories (Elliot, 1980;Katsuyama, 1980):sulfated
alcohols; sulfated hydrocarbons; aryl alkyl polyether sulfates; sulfonated
amides; and alkyl aryl sulfonates.Anionic wetting agents,across all classes,
exhibit good to excellent detergency withmoderateto highfoamproduction.
Cationicwettingagents are limited to the quaternaryammoniumcompounds
(QACs).As wetting agents,QACsare not as efficientas anionic or non-ionic
compounds(Elliot, 1980 ; Katsuyama,1980).Cationicwettingagentsalso tend
to reactunfavorably withmineralsand foodsoils.Theyhavelow levelsof
detergencyand are therefore of little use in cleaning applications.By contrast,
QACs do havegoodantibacterial properties(Elliott, 1980)whichmake themof
interest as disinfectants or sanitizingagents.Amphoteric wettingagentsare
compatiblewithcationic,anionic and non-ionic wetting agentsas wellas with
some soap(Elliott,1980).Theyworkby looseningand softeningproteinand
carbohydrate soil types. Amphoteric-type detergents are widely used for
cleaningfoodcontactsurfaces.
The remaining majorclassof wetting agentscomprisesthe non-ioniccom-
pounds. The materials in this classdo not dissociate when dissolved in waterand
havethe broadest rangeof cleaning properties. Theyare betterdetergents for oil
than the anionic or cationic species. Non-ionic wetting agents are only
marginallyaffectedby waterhardness (Elliot,1980;Katsuyama,1980). They
also varyconsiderablywithregard to theirfoaming properties.Foam-producing
capacity is a function of the ratioof the hydrophilic/hydrophobic balance.This
balance is influencedby the temperature of the cleaningsolution.For example,
withan increasein the temperature of the cleaning solution the hydrophobic
property and solubilityof a non-ionicwetting agentdecreases. At the pointof
minimum solubility(cloudpoint),non-ionicsurfactants generally act as de-
foamers. At conditionsbelowthe cloudpointthey varyconsiderablywith regard
to theirfoamproducing properties(ArizonaDepartment of HealthServices,
2003).
Chemicallyactivecleaningcompounds
Compounds that reactchemicallywithsoilsto affectcleaningincludebothacid
and alkaline types of detergents. Acid cleaners are compounds that are
formulated witheitherorganic or inorganicacids.Organicacidsare also called
weak acids.Common organicacidsincludeacetic, butyric,citric,and lactic acid.
By contrast the inorganic acids,also called mineral or strongacids, include
hydrochloric (HCl),sulfuric (H 2 SO 4 ), nitric (HNO 3 ) and phosphoric acids
(H 3 PO 4 ).
The hydrogen ion (H+) is the activeingredientin bothstrongand weakacids.
The reactionbetween the foodsoil and acidcausesthe soil to break-downand
454 Handbookof hygiene controlin the foodindustry