Food SoilFood Soil

Soil deposits are complex mixtures of Soil deposits are complex mixtures of organic and inorganic materials.organic and inorganic materials.

Physical Characteristics of SoilPhysical Characteristics of Soil

The type of surface to be cleaned affects The type of surface to be cleaned affects the type of soil that collects and how it is the type of soil that collects and how it is removed. Soil is difficult to remove from removed. Soil is difficult to remove from cracks, crevices and other uneven cracks, crevices and other uneven surfaces. surfaces.

It is easiest to remove soil from smooth It is easiest to remove soil from smooth hard nonporous surfaces.hard nonporous surfaces.

Types of SoilsTypes of Soils The table below shows the four basic The table below shows the four basic

food soil residues left on processing food soil residues left on processing equipment.   equipment.  

Depending upon the food product being Depending upon the food product being manufactured and the process manufactured and the process equipment used, varying degrees of food equipment used, varying degrees of food soil will be deposited on the equipment soil will be deposited on the equipment during production. during production. 

These food soils will require complete These food soils will require complete removal during the cleaning process and removal during the cleaning process and will affect the cleaning compound used, will affect the cleaning compound used, along with the method of cleaning. along with the method of cleaning.

Deposit Solubility Removal Process Heat Effects Deposit Solubility Removal Process Heat Effects SugarsSugars Water Soluble Water Soluble Easy Easy Caramelization makes Caramelization makes

removal more difficult removal more difficult Fats Fats Water Insoluble Water Insoluble Alkaline Soluble Alkaline Soluble DifficultDifficult Polymerization makes Polymerization makes

removal more difficult removal more difficult ProteinsProteins Water Insoluble Water Insoluble Alkaline Soluble Alkaline Soluble Slightly Acid Soluble Slightly Acid Soluble Very DifficultVery Difficult Denaturation makes Denaturation makes

removal more difficult removal more difficult MineralsMinerals Water Soluble Water Soluble Acid Soluble Acid Soluble Easy to DifficultEasy to Difficult Reaction with other Reaction with other

soilssoils

Types of Soils³Types of Soils³Type of Soil Type of Soil Soil SubclassSoil Subclass Examples ExamplesInorganic soils Inorganic soils Hard-water depositsHard-water deposits Calcium and magnesium Calcium and magnesium carbonates carbonates Metallic depositsMetallic deposits Common rust, other oxides Common rust, other oxides Alkaline depositsAlkaline deposits Films left when an alkaline Films left when an alkaline cleaner is not rinsed off cleaner is not rinsed off properly properly Organic soils Organic soils Food depositsFood deposits Food scraps and specs Food scraps and specs Petroleum depositsPetroleum deposits Lubrication oils, grease, Lubrication oils, grease, and other lubricants and other lubricants

Nonpetroleum depositsNonpetroleum deposits Animal fats Animal fats and and vegetable oilsvegetable oils

Soil deposits are often complex mixtures Soil deposits are often complex mixtures of organic and inorganic materials. of organic and inorganic materials.

It is important to know the type of soil It is important to know the type of soil and use the best cleaning compound or and use the best cleaning compound or combination of compounds to remove it.combination of compounds to remove it.

A two-step cleaning procedure (using A two-step cleaning procedure (using more than one cleaning compounds) is more than one cleaning compounds) is often needed to remove a combination of often needed to remove a combination of inorganic and organic deposits. inorganic and organic deposits.

Table shows the best type of cleaning Table shows the best type of cleaning compounds for each type of soil. compounds for each type of soil.

Type of Soil Type of Soil Cleaning CompoundCleaning Compound

Inorganic soils Acid Cleaner Inorganic soils Acid Cleaner

Organic soilOrganic soil

——Nonpetroleum Alkaline CleanerNonpetroleum Alkaline Cleaner

— —Petroleum Solvent CleanerPetroleum Solvent Cleaner

Fat-based SoilsFat-based Soils

Fat usually is present as an emulsion Fat usually is present as an emulsion and can generally be rinsed away and can generally be rinsed away with hot water above thewith hot water above the

melting point. More difficult fat and melting point. More difficult fat and oil residues can be removed with oil residues can be removed with alkaline detergents which have good alkaline detergents which have good emulsifying or saponifying emulsifying or saponifying ingredients.ingredients.

Protein-based SoilsProtein-based Soils In the food industry, proteins are by far In the food industry, proteins are by far

the most difficult soils to remove. the most difficult soils to remove. In fact, casein (a major milk protein) is In fact, casein (a major milk protein) is

used for its adhesive properties in many used for its adhesive properties in many glues and paints. glues and paints.

Food proteins range from more simple Food proteins range from more simple proteins, which are easy to remove, to proteins, which are easy to remove, to more complex proteins, which are very more complex proteins, which are very difficult to remove. difficult to remove.

Heat-denatured proteins can be Heat-denatured proteins can be extremely difficult. extremely difficult.

Generally, a highly alkaline detergent Generally, a highly alkaline detergent with peptizing or dissolving properties with peptizing or dissolving properties is required to remove protein soils. is required to remove protein soils.

Wetting agents can also be used to Wetting agents can also be used to increase the wettability and increase the wettability and suspendability of proteins. suspendability of proteins.

Protein films require alkaline cleaners Protein films require alkaline cleaners which have hypochlorite in addition to which have hypochlorite in addition to wetting agents.wetting agents.

Carbohydrate-based SoilsCarbohydrate-based Soils

Simple sugars are readily soluble in Simple sugars are readily soluble in warm water and are quite easily warm water and are quite easily removed.removed.

Starch residues, individually, are also Starch residues, individually, are also easily removed with mild detergents.easily removed with mild detergents.

Starches associated with proteins orStarches associated with proteins or

fats can usually be easily removed by fats can usually be easily removed by highly alkaline detergents.highly alkaline detergents.

Mineral Salt-based SoilsMineral Salt-based Soils

Mineral salts can be either relatively easy Mineral salts can be either relatively easy to remove, or be highly troublesome to remove, or be highly troublesome deposits or films.deposits or films.

Calcium and magnesium are involved in Calcium and magnesium are involved in some of the most difficult mineral films. some of the most difficult mineral films.

Under conditions involving heat and Under conditions involving heat and alkaline pH, calcium and magnesium can alkaline pH, calcium and magnesium can combine with bicarbonates to form highly combine with bicarbonates to form highly insoluble complexes.insoluble complexes.

Other difficult deposits contain iron Other difficult deposits contain iron or manganese. or manganese.

Salt films can also cause corrosion of Salt films can also cause corrosion of some surfaces. some surfaces.

Difficult salt films require an acid Difficult salt films require an acid cleaner (especially organic acids cleaner (especially organic acids which form complexes with these which form complexes with these salts) for removal. salts) for removal.

Sequestering agents such as Sequestering agents such as phosphates or chelating agents are phosphates or chelating agents are often used in detergents for salt film often used in detergents for salt film removal.removal.

Microbiological FilmsMicrobiological Films Under certain conditions, Under certain conditions,

microorgranisms (bacteria, yeasts, microorgranisms (bacteria, yeasts, and molds) can form invisible films and molds) can form invisible films (biofilms) on surfaces. (biofilms) on surfaces.

Biofilms can be difficult to remove Biofilms can be difficult to remove and usually require cleaners as well and usually require cleaners as well as sanitizers with strong oxidizing as sanitizers with strong oxidizing properties.properties.

Lubricating Greases and OilsLubricating Greases and Oils These deposits (insoluble in water, alkali, These deposits (insoluble in water, alkali,

or acid) can often be melted with hot or acid) can often be melted with hot water or steam, but often leave a residue. water or steam, but often leave a residue.

Surfactants can be used to emulsify the Surfactants can be used to emulsify the residue to make it suspendable in waterresidue to make it suspendable in water

and flushable.and flushable.

Other Insoluble SoilsOther Insoluble Soils

Inert soils such as sand, clay, or fine Inert soils such as sand, clay, or fine metal can be removed by surfactant-metal can be removed by surfactant-based detergents. based detergents.

Charred or carbonized material may Charred or carbonized material may require organic solvents.require organic solvents.

Quantity of SoilQuantity of Soil It is important to rinse food-contact It is important to rinse food-contact

surfaces prior to cleaning to remove surfaces prior to cleaning to remove most of the soluble soil. most of the soluble soil.

Heavy deposits require more Heavy deposits require more detergent to remove. Improper detergent to remove. Improper cleaning can actually contribute to cleaning can actually contribute to build-up of soil.build-up of soil.

The Surface CharacteristicsThe Surface Characteristics

The cleanability of the surface is a The cleanability of the surface is a primary consideration in evaluating primary consideration in evaluating cleaning effectiveness.cleaning effectiveness.

Important surface characteristics are:Important surface characteristics are: Surface Composition.Surface Composition. Surface Finish.Surface Finish. Surface Condition.Surface Condition.

Surface CompositionSurface Composition Stainless steel is the preferred surface Stainless steel is the preferred surface

for food equipment and is specified in for food equipment and is specified in many industry and regulatory design many industry and regulatory design and construction standards. and construction standards.

For example: 3-A Sanitary Standards For example: 3-A Sanitary Standards (equipment standards used for milk (equipment standards used for milk and milk products applications) specify and milk products applications) specify 300 series stainless steel or equivalent. 300 series stainless steel or equivalent. Other grades of stainless steel may be Other grades of stainless steel may be appropriate for specific applications (i.e appropriate for specific applications (i.e 400 series) such as handling of high fat 400 series) such as handling of high fat products, meats, etc. products, meats, etc.

““Soft” metals & otherSoft” metals & other Other "soft" metals (aluminum, brass, Other "soft" metals (aluminum, brass,

copper, or mild steel), or nonmetallic copper, or mild steel), or nonmetallic surfaces (plastics, or rubber) are also used surfaces (plastics, or rubber) are also used on food contact surfaces. on food contact surfaces.

Surfaces of soft metals and nonmetallic Surfaces of soft metals and nonmetallic materials are generally less corrosion- materials are generally less corrosion- resistant and care should be exercised in resistant and care should be exercised in their cleaning. their cleaning.

Aluminum is readily attacked by acids as Aluminum is readily attacked by acids as well as highly alkaline cleaners which can well as highly alkaline cleaners which can render the surface non-cleanable.render the surface non-cleanable.

Plastics are subject to stress cracking Plastics are subject to stress cracking and clouding from prolonged and clouding from prolonged exposure to corrosive food materials exposure to corrosive food materials or cleaning agents. or cleaning agents.

Hard wood (maple or equivalent) or Hard wood (maple or equivalent) or sealed wood surfaces should only be sealed wood surfaces should only be used in limited applications such as used in limited applications such as cutting boards or cutting tables cutting boards or cutting tables provided the surface is maintained in provided the surface is maintained in good repair. good repair.

Avoid using porous wood surfaces.Avoid using porous wood surfaces.

Surface FinishSurface Finish Equipment design and construction Equipment design and construction

standards also specify finish and standards also specify finish and smoothness requirements. smoothness requirements.

3-A standards specify a finish at least 3-A standards specify a finish at least as smooth as a No. 4 ground finish as smooth as a No. 4 ground finish for most application. for most application.

With high-fat products, a less smooth With high-fat products, a less smooth surface is used to allow product surface is used to allow product release from the surface.release from the surface.

Surface ConditionSurface Condition

Misuse or mishandling can result in Misuse or mishandling can result in pitted, cracked, corroded, or pitted, cracked, corroded, or roughened surfaces. roughened surfaces.

Such surfaces are more difficult to Such surfaces are more difficult to clean or sanitize, and may no longer clean or sanitize, and may no longer be cleanable. be cleanable.

Thus, care should be exercised in Thus, care should be exercised in using corrosive chemicals or corrosive using corrosive chemicals or corrosive food products.food products.

Removal of soil from a surface takes Removal of soil from a surface takes three steps. three steps.

FirstFirst, soil must be separated from , soil must be separated from

the surface. the surface.

SecondSecond, the soil must be dispersed , the soil must be dispersed

into the cleaning solution.into the cleaning solution.

ThirdThird soil must not be allowed to soil must not be allowed to

reattach to the surface.reattach to the surface.

Soil can be separated from a surface Soil can be separated from a surface mechanically by using high pressure mechanically by using high pressure water, steam, air or scrubbing. water, steam, air or scrubbing.

Soil can also be separated from a Soil can also be separated from a surface chemically. surface chemically.

A chemical example would be using A chemical example would be using an alkaline cleaner with a fatty acid an alkaline cleaner with a fatty acid to form a soap.to form a soap.

The soil and surface must be thoroughly The soil and surface must be thoroughly wet for a cleaning compound to help wet for a cleaning compound to help separate the soil from the surface. separate the soil from the surface.

The cleaning compound helps loosen the The cleaning compound helps loosen the soil from the surface by reducing the soil from the surface by reducing the strength of the bond between the surface strength of the bond between the surface and the soil. and the soil.

Heat or mechanical action (scrubbing, Heat or mechanical action (scrubbing, shaking, high pressure spray, etc.) can shaking, high pressure spray, etc.) can help reduce the bond. help reduce the bond.

However, heat does not help loosen some However, heat does not help loosen some protein and fat soils.protein and fat soils.

Once the soil has been separated Once the soil has been separated from the surface it needs to be from the surface it needs to be dispersed into the cleaning solution. dispersed into the cleaning solution.

Therefore, enough cleaning solution Therefore, enough cleaning solution must be used to dissolve all the soil. must be used to dissolve all the soil. Some soils will not dissolve in the Some soils will not dissolve in the cleaning solution. cleaning solution.

It is important to break up the It is important to break up the undissolved soil into smaller particles undissolved soil into smaller particles so it can be carried away from the so it can be carried away from the surface. surface.

Mechanical action such as scrubbing, Mechanical action such as scrubbing, shaking or high pressure sprays help shaking or high pressure sprays help to break the soil down into smaller to break the soil down into smaller particles. particles.

Cleaning solutions should be Cleaning solutions should be changed often enough to prevent changed often enough to prevent dispersed soil from reattaching.dispersed soil from reattaching.

A clean surface should be rinsed or A clean surface should be rinsed or flushed to remove all dispersed soil flushed to remove all dispersed soil and cleaning residues. and cleaning residues.

Using soft water helps prevent Using soft water helps prevent deposits formed when hard water deposits formed when hard water reacts with soap in a cleaning reacts with soap in a cleaning compound.compound.