is a necessaryfirststepin the processof selectingan appropriatecleaning
agentor detergent.
Detergenttype
Cleaning compounds are routinely assignedone of fiveclassifications:basic
alkalis;complexphosphates; surfactants; chelatingagents; and acids(Bakka,
1997).Occasionally detergentsare formulatedusing enzymesthat catalytically
reactwithspecificfoodsoil componentsto causetheirdegradation.However,
the vast majority of cleaning compoundsare formulatedto perform the cleaning
related functions summarized in Table 28.4. Detergents and cleaning
compounds are most oftena mixtureof ingredientsthat are formulated to react
withfoodsoil by eithera physical or chemicalmeans.
Physical acting cleaning compounds
Physical actingdetergents alterthe properties of the targeted foodsoil.For
example, compoundsof this classmay alterthe solubilityor colloidal stabilityof
the soil.Surfactants,or surfaceactingcompounds,are examples of agentsthat
workby wayof a physicalmechanism. The most efficientcompoundsof this
classhavea chainlength of between 13 and 15 carbonatoms(Elliot, 1980;
Katsuyama,1980).Theseorganic compoundshavefunctionalpropertieswherea
portionof theirmolecularstructureis hydrophilic(water-loving) and a portion is
hydrophobic(repulsed by water). Surfactantsfunction in cleaningcompounds
by promotingthe physicaldispersion, emulsification,penetrations,foamingor
wettingof the target soil.Surface acting agents are eitherionicor non-ionic
(Elliott,1980). Ionicsurfactantsare divided furtherinto threesub-classes:
anionic(negativelychargedin water),cationic(positivelycharged in water) and
amphoteric (charge is pH dependent).Amphoteric surfactants are cationic under
acidconditionsand anionic underalkalineconditions.
Table28.4 Cleaningcompoundeffectivenessby classand cleaningfunction(after
Guthrie,1972)
Cleaningfunction Strong Mild Poly- Weak Strong Surfactants
alkalis alkalis phosphates acids acids
Chelating 0 1 4 0 0 0
Saponification 4 3 3 3 3 1
Wetting 1 2 1 1 0 4
Peptizing 4 3 1 2 3 0
Emulsification 1 2 2 0 0 4
Dispersion 2 3 1 3 0 3
Rinsing 3 3 2 1 0 4
Corrosion 4 2 0 2 4 0
Key:4 = excellent; 3 = verygood;2 = moderate;1 = low;0 = none.
Improvingcleaning-out-of-place(COP) 453