Principles of Food Sanitation

important to identify correctly the type of
deposit and to use the most effective cleaning
compound or combination of compounds
to effectively remove soil deposits. It is fre-
quently essential to utilize a two-step cleaning
procedure that contains more than one clean-
ing compound to remove a combination of
inorganic and organic deposits. Table 9–3
illustrates the types of cleaning compounds
applicable to the broad categories of soil pre-
viously discussed.

Chemical Characteristics

Surface attachment is influenced by the
chemical and physical properties of soil, such
as surface tension, wetting power, and chemi-
cal reactivity with the surface of attachment;
and by physical characteristics, including par-
ticle size, shape, and density. Some soils are
held to a surface by adhesion forces, or dis-
persion forces. Certain soils are bonded to the
surface activity of the adsorbed particles.
Adsorption forces must be overcome by a sur-

factant that reduces surface energy of the soil

and subsequently weakens the bond between

the soil and surface of attachment.

Physical characteristics of soil can also

affect adhesion strength, which is directly

related to environmental humidity and time

of contact. Adhesion forces are also depend-

ent on geometric shape, particle size, surface

irregularities, and plastic properties. Mechan-

ical entrapment in irregular surfaces and

crevices contributes to the accumulation of

soils on equipment and other surfaces.

Effects of surface characteristics on soil deposition

Surface characteristics should be consid-

ered when selecting a cleaning compound and

cleaning method (Table 9–4). Clearly, the

equipment and building material used, affects

soil deposition and cleaning requirements.

Sanitation specialists should be thor-

oughly familiar with all finishes used on

equipment and areas in the food facility and

should know which cleaning chemicals will

attack surfaces. If the local management

team is unfamiliar with the cleaning com-

pounds and surface finishes, a consultant or

reputable supplier of cleaning compounds

should be sought to provide technical assis-

tance, including recommending chemicals

and sanitation procedures.

Cleaning Compounds 143

Table 9–2Classification of Soil Deposits

Type of Soil Soil Subclass Deposit Examples

Inorganic soil Hard-water deposits Calcium and magnesium carbonates
Metallic deposits Common rust, other oxides
Alkaline deposits Films left by improper rinsing after use of an alkaline
cleaner
Organic soil Food deposits Food residues
Petroleum deposits Lubrication oils, grease, and other lubrication products
Nonpetroleum deposits Animal fats and vegetable oils

Table 9–3Types of Cleaning Compounds for
Soil Deposits

Required Cleaning

Type of Soil Compound

Inorganic soil Acid-type cleaner
Organic soil
(Nonpetroleum) Alkaline-type cleaner
(Petroleum) Solvent-type cleaner