1. MADISON CHEMICAL FOOD DIVISION CHEMISTRY of CLEANING
Bonnie Hare – Director-Food Division

2. Why do we clean a Food Plant?
To meet governmental standards
To remove and prevent bacterial buildup
To prevent insect and rodent harborage
To remove old soils that will contaminate the next food process
To remove odor causing bacteria
To reduce the chance of off flavors
To improve the shelf life of the food
To prevent the staining and filming of the equipment
To increase the thermal efficiency of the equipment
To lengthen the life of the equipment
To increase the pride in the operation of the plant

3. Soils 2 Basic Categories of soil: Typical -
Soils from the raw materials, water and environment
Atypical -
Food additives, factory soils, unusual water components

4. Typical Soils Found in Food Plants
Soil Type
Description
Cause
Removal
Protein
Blue-rainbow hue to a yellowish-brown rainbow hue.
Using non-chlorinated cleaner. Inadequate pre-rinse. Improper detergent concentrations, water temperature too low.
Appropriate Chlorinated Alkaline cleaning.
Mineral (Calcium, Magnesium)
White to yellow.
Mineral from products or from water.
Acid cleaning.
Insoluble Organics (Fats, Flavors, Pigments)
Hanging water droplets. Greasy (white) appearance.
Low temperature or weak detergent concentration.
Hot, chlorinated alkaline cleaning.
Carbohydrates
Clear to brown film, sticky
Sugars and starches precipitated or burned on.
Hot alkaline wash.

5. Atypical Soils Found in Food Plants
Soil Type
Description
Cause
Removal
Iron
Reddish to brown.
Water supply. Iron from system components.
Acid cleaning.
Silica
White to gray glazed appearance.
Process water, Allowing soft metal safe (silicate) detergents to dry.
Special acid containing fluorides.
Factory Soil
Grease, factory dirt, black deposit, rusting.
Improper initial cleanup of new equipment; leaks or over-greasing.
Emulsifying, alkaline cleaning.
Titanium Dioxide, Esters, Gums
White, chalky, sticky.
Re-deposition.
Special procedures.

6. BASIC CLEANING CHEMISTRY
Define:
Cleaning:
The removal of soil from a surface in preparation for sanitizing.
Sanitizing:
Reducing the number of microorganisms that are on a properly cleaned surface to a safe level. (99.999% microorganism free)
Disinfection:
Also reducing the number of microorganisms that are on a properly cleaned surface but reducing the number by one more log to % microorganism free.

7. CHEMISTRY OF CLEANING
Removing soil in the most economical manner possible using chemicals (detergents) is the chemistry of cleaning.
The following terms describe and explain the properties or functions of chemical detergent application to remove soils:
Emulsification – the breaking up into small particles of non-water soluble substances such as fats and oils. Certain chemicals will break up fats and oils into extremely small particles or droplets so they can mix or “emulsify” with water. In this state oily soils can be easily flushed away with water.
Dispersion – the breaking up of solid soils into small particles. When these soils are finely divided or “dispersed” in water, they too can be flushed away.
Saponification – the actual chemical reaction between a chemical called an “alkali” and a fat, resulting in a soluble soap. Since the fat has been made soluble by this reaction, not only is it easy to remove but, in some instances, can actually aid in cleaning. This is the historical method of making soap.

8. CHEMISTRY OF CLEANING Continued
Wetting/Penetrating/Surface Tension – the cleaning solution must wet all surfaces and penetrate through the soils to remove them from the surface. The use of proper wetting agents (surfactants) actually makes the water “wetter” to allow the cleaning solution to better penetrate the soil. Lowering the surface tension allows the cleaning solution and oils/soils to mix.

9. CHEMISTRY OF CLEANING Continued
Water Conditioning – is often referred to as softening, sequestration or chelation. Water contains dissolved minerals picked up on its passage through the ground. These minerals interfere with the action of cleaners. Minerals appear as scale when they dry on surfaces. To improve the cleaning ability of a product, chemicals are added to tie up or hold these minerals so they cannot interfere. Depending on how these minerals are held, the words sequestration or chelation can be used.
Corrosion Inhibition – occurs when cleaners are designed to remove soils without damaging the surface being cleaned. Certain chemicals are used to prevent unwanted attack or corrosion, allowing the cleaner to effectively work on the soils without attacking the surface being cleaned.

10. CHEMISTRY OF CLEANING Continued
Rinsing is not as straightforward as it may seem. For cleaners to effectively remove soil, they along with the soils they have cleaned must be rinsed completely from the surface. Cleaners must be free rinsing or the soils removed from the surface will be redeposited in the final rinse operation resulting in a dull, filmed surface.
Solubilizing or Dissolving is the reaction of a soil with a cleaner that produces water soluble products. When these normally insoluble soils are dissolved or solubilized, they are readily rinsed from the surface
Peptizing – the process of forming a stable dispersion of proteins

11. A Good Detergent does the following:
1. Dissolves rapidly and completely in water. 2. Softens the water to prevent the precipitation of minerals from the water. 3. Emulsifies soils, especially oils. 4. Disperses solid soils evenly throughout the cleaning solution. 5. Is non-corrosive to the surface being cleaned. 6. Rinses easily and completely. 7. Remains stable in storage. 8. Is appropriate for use with the protective clothing and equipment available. 9. Is economical a use concentrations. 10. Is compatible with waste treatment.

12. Cleaning Detergents
2 Primary Categories
Alkaline
Acid

13. Cleaning Detergents
What does the pH scale mean? The pH scale is a measure of the acidity or alkalinity of soluble substances in a water-based solution. pH stands for ‘potential of Hydrogen’. The scale ranges from 0 to 14. A pH lower than 7 indicates the solution is an acid. If the pH is above 7 this indicates it is a base or alkaline. A pH of 7 is neutral.

14. Cleaning Detergents
What does the pH scale actually measure? pH is the measure of the Hydrogen ions (H+) in the solution. In water (H2O), a small number of molecules dissociate (split up). Some of the water molecules lose a hydrogen and become hydroxide ions (OH-). The “lost” hydrogen ions join up with water molecules to form hydronium ions (H3O+). For simplicity, hydronium ions are referred to as hydrogen ions (H+). In pure water there are an equal number of hydrogen ions and hydroxide ions. The solution is neutral.

15. Cleaning Detergents
An acid donates hydrogen ions. Because of this, the balance between hydrogen ions and hydroxide ions is shifted. Now there are more hydrogen ions (H+) in the solution. An alkaline solution accepts hydrogen ions. Because of this, the balance between hydrogen ions and hydroxide ions shifts the opposite way. Since the alkaline solution “soaks up” hydrogen ions, the solution has more hydroxide ions (OH-).

16. Cleaning Detergents
What does all this mean in ‘real life’? Sulfuric acid (Battery acid) has a hydrogen ion concentration 10 million times higher than water. Sodium hydroxide (lye) has a hydroxide ion (OH-) concentration 10 million times higher than water. The higher the ion concentration, the more reactive the solution and the greater ability to clean surfaces (and the greater the ability to cause skin burns).

17. Alkaline Detergent Components
Compound
Function
Alkalis
Peptizes proteins (makes a stable dispersion), saponifies fats, and emulsifies fats
Surfactants
Penetrate, lift and disperse soils, prevent soil redeposition
Phosphates
Peptizes proteins, emulsifies, aids in soil dispersion, softens water, prevents soil redeposition
Chelating Agents
Softens water, aids in mineral deposit control, prevents soil redeposition
Chlorine
Reacts with proteins and aids in removal
Solvents
Dissolves grease and aids in removal

18. Acid Detergent Components
Acids – dissolve inorganic soils such as mineral deposits.
Surfactants – penetrate and lift soils

19. Application of Cleaners
Soil
Cleaner type
Heavy, burnt-on soils
High Alkaline / Caustic cleaner
Normal soils
Alkaline foaming cleaner or low foam CIP cleaner
General cleaning of soft metals (aluminum)
Neutral or Inhibited cleaner
Floors
Alkaline / Solvent cleaner
Mineral deposits
Acid cleaners
Silica film
Acid cleaners containing fluorides

20. Sanitizers Quickly destroy disease and spoilage causing organisms.
Do not adversely affect equipment, product or consumer health
Must be EPA registered and meet the government Code of Federal Regulations

21. Types of Sanitizers Non-Residual (Oxidizing): Residual
Chlorine Containing
Peracetic Acid
Residual
Iodine
Acid Anionic
Quaternary Ammonium Compounds

22. Chlorine Sanitizers – work by oxidizing the chemical bonds of the bacterial or viral cell causing the molecule to fall apart.
Advantages
Disadvantages
Effective against a wide variety of bacteria including spores and bacteriophages
Relatively inexpensive
Not affected by hard water salts
Concentration easily measured
Corrosive to many metals
Irritating to skin and mucous membranes
Dissipates rapidly from solution
Effectiveness decreases with increases in pH
Activity decreases rapidly in presence of organic matter
Odor can be offensive

23. Iodine based Sanitizers – work by reacting with amino acids in the cell membrane disrupting the respiratory process.
Advantages
Disadvantages
Strength indicated by color change
Noncorrosive
Nonirritating to skin
Effect against a wide variety of microorganisms
Easily titrated
Prevents film formation due to its acid nature
Stable shelf life
Higher in cost
Can stain many surfaces
Temperature should not exceed 120°F
Less effective against bacterial spores than chlorine.

24. Quaternary Sanitizers – Quat binds irreversibly to phospholipids and proteins of the bacterial or viral cell membrane. This increases permeability of the cell wall and allow the quat to enter and destroy the cell.
Advantages
Disadvantages
Relatively nontoxic, odorless and colorless, noncorrosive
Stable to heat
Stable in presence of organic matter
Eliminates odors
Forms bacteriostatic film
Active in a wide pH range and against many microorganisms
Not compatible with anionic cleaners
Foaming problems in mechanical systems
Film forming
Not effective against TB and certain viruses
Not effective against spores

25. Acid Anionic Surfactants – Hydrogen ions destroy the amino-acid bond in the cell’s DNA modifying the pH and precipitating the cell’s proteins.
Advantages
Disadvatages
Nonstaining
Minimal odor
Removes and prevents scale and milkstone
Effective against a wide variety of microorganisms
Stable in concentrates and in use dilution
Not affected by water hardness
Effective at acidic pH, less effective above a pH of 2.2
Generates foam
Slow activity against spore formers
Low effectiveness agains Lactobacillus, yeast and mold

26. Peroxyacetic acid (PAA) – oxidizes and denatures proteins and lipids of bacterial and viral cells leading to disorganization of the cell membrane.
Advantages
Disadvantages
Effective against a wide variety of bacteria including bacteriophages
Kills rapidly
Not affected by hard water
Very effective in cold water
Relatively stable use solution
Corrosive to some metals
Irritating to skin and mucous membranes
Unstable in hot water (140°F)

27. CHEMICAL STORAGE Which is proper storage?
All chemicals should be stored in a secure (lockable), cool, dry area with proper ventilation. There must be unobstructed access to an eyewash and safety shower within 10 seconds of the storage area. There should be spill containment for all chemicals and acid and alkaline products should be separated. Everything should be labeled – all chemical application equipment and containers and the storage area for each chemical. Flammables must be stored in a proper storage cabinet.
Which is proper storage?

28. 6 STEPS TO EFFECTIVE WET SANITATION
1. Preparation – Secure and disassemble equipment, Remove gross soils from equipment and floor. Remove production supplies and trash, Empty Drain Baskets.
2. Pre-Rinse – Remove the remaining visible soils with warm to hot water (110 – 150°F). Parts should be rinsed and ready to place into COP tanks for cleaning. Rinse equipment from top to bottom, rinse floor.
3. Wash – Foam the walls, then the floors followed by the equipment. Allow the appropriate contact time, but do not allow the cleaner to dry. Scrub to remove films, fats and proteins. Clean drains last.
4. Post Rinse – Remove cleaner and soils with a flooding rinse. Rinse with cool water in the order that cleaner was applied (Walls, floor, then equipment).
5. Inspect - Use a flashlight to verify area is clean looking for soil, hazes or water beading on surfaces. Verify by sight, feel and smell.
6. Sanitize – Remove standing water prior to sanitizing. Flood sanitize walls and floors before the equipment, sanitizing the food contact areas last.

29. Pre-Rinse Removes gross soil deposits to allow cleaning solutions to clean the surface of the equipment. Control of the water temperature is essential to avoid problems.
Disassemble equipment
Water below 140°F (60 C) will not dissolve fats or grease.
Water above 160°F (71 C) cooks soils, coagulates proteins, and precipitates water hardness onto equipment.
Rinse from top to bottom
Thoroughly rinse the floor

30. How do you effectively clean?
The Wash step involves four principles:
Application
Concentration
Time
Temperature

31. Cleaning Application Methods
Manual – brushes and scrub pads
Soak – tanks, buckets
Spray – flooding with cleaner
Clean in Place (CIP) – high velocity
Clean out of Place (COP) – adds agitation and heat
Foam – allows extended contact time
Gel – even longer contact time
High Pressure – use impingement to clean

32. Application
The combination of Soak and Agitation determines the success of cleaning. More contact time allows the cleaner to penetrate and loosen soils. Soaking can be in the form of extended spray, foam or gel contact, CIP or COP. Agitation breaks up soils so that the detergency can disperse, dissolve, solubilize or emulsify the soils and allow them to be easily rinsed away.

33. Concentration
Concentrations used are determine by a combination of effectiveness and economy. The longer a cleaner has contact with the soil the lower the concentration that can be effectively used. More is not better, using the correct concentration will give excellent cleaning and value.

34. Typical Concentrations by application
Manual Alkaline: 3 – 5% by volume
CIP Alkaline: – 1.0% by volume
Manual Acid: 1 – 5% by volume
CIP Acid: – 1.0% by volume

35. Temperature
Manual: 110°F – 140°F CIP: 130°F – 170°F Temperature is a very important component in cleaning. Warm to very warm solutions react much more quickly with soils and more effectively dissolve oils. Using solutions which are hot are a danger to the sanitors, can actually burn soils onto the equipment surface and dry too quickly making them difficult to rinse from the surface.

36. Temperature effect
Temperature is another way of adding energy to the cleaning process. If your cleaning temperature is not as high as normal you will need to increase concentration or contact time or both.

37. The one thing we never have enough of!
Time
The one thing we never have enough of!
Manual: 5 – 10 minutes
CIP: Depends on length of circuit and velocity of solution
Any reduction in cleaning time
requires an increase in temperature
or concentration for equal cleaning.

38. Post-Rinse Always clean your drains before the Rinsing process begins!
Remove cleaner and soil with a low pressure, flood rinse.
Use cool to warm water.
Rinse from top to bottom.
Do not use high pressure.
Do not cross-contaminate.

39. Inspection
Look at all surfaces! There should be no soils, hazes or water beading on equipment surfaces.
Verify by sight, feel and smell.
Use a flashlight to verify cleaning.
Look underneath, around, above – any difficult place to see is difficult to clean!
Look for crevices and likely hiding places.

40. Sanitize
Put on clean outerwear and sanitize hands. Remove all standing water and overhead condensation before sanitizing. Sanitize floors first, then equipment, ending with food contact surfaces. Cover surfaces thoroughly. Follow all sanitizer label directions.