Chemistry of Cleaning In Food Processing Plants
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Chemistry of Cleaning In Food Processing Plants Plant Sanitation Training Dallas, TX October 9th and 10th 2013 Public 1 Agenda • Four Fundamental Principals • Water • Additives & Surfactants • pH – Acid/Alkali Strengths • Soils & Detergents • Alkalinity/Alkaline Detergents • Acidity/Acid Detergents • Chlorine Detergents Public Four Fundamental Principals Public Components for Effective Cleaning Water – Universal Solvent Detergents • Alkaline • Acids • Lo Foam • Hi Foam Additives • Surfactants • Chelators • De-Foamers Public Soils • Milkstone • Fats • Oils • Protein Removes Agenda •Water Public Water • Water is the single most important ingredient in an effective wash program. Water acts as: • Solvent and carrier: • Solvent for soil removal and carrier of detergents • Approximately 90% of the soil is removed during the first rinse step • Key Cleaning Point • Concept of “Superior” Rinse Public Water (cont.) • Turbulant Flow of Water on surfaces acts as a cleaning solutions are driven through the system (hydraulic action). • Heat Transfer Agent allows heat energy to accelerate chemical reactions throughout the system. Public Water Quality Issues • Dissolved minerals (calcium and magnesium salts) can interfere with chemicals used to remove soils – “water hardness effect.” • Other mineral salts that may leave deposits on surfaces – barium sulfate, silica. Public Water Quality Issues (cont.) • Iron – Leaves rust colored deposits. • Buffering capacity – impact on alkaline detergents, acids, and sanitizers. • High levels of silica in water can result in difficult to remove hard water films. • Dissolved organic material that may interfere with cleaning compounds. • So what can be done? Public Agenda •Additives & Surfactants Public Additives Built in Detergents or Added Separately Additives: • Chelating Agents: • Surfactants • De-foamers • Additives work best when added to the water prior to the detergent • Cost Effective application Public Additives in the Detergent Additives: • Chelating Agents: • Tie up hardness (calcium and magnesium) on a one-to-one basis. The harder the water, the more that is needed. • They soften in water • Prevent soap film from forming • Improved rinsibility • Reduce necessary acid washes Public Surfactants – Surface Active Agents Additives: • Surfactants • Surface tension prevents proper contact with the cleaning solution. • A surfactant will help the solution to reach all surfaces of the soil and lower surface tension. Public Surfactants • Surfactant additives to aid in the cleaning process. • Lower surface tension. • Help detach fats from surface. • Help suspend soils. • Must be low foam for CIP. Public De-Foaming Additives Additives: • DeFoamers: • Defoaming surfactants aid in the cleaning process by reducing foam and eliminating pump cavitation • You can’t pump foam • Help detach fats and oils from the surface. • Suspend and hold the soil in suspension Public Agenda •pH – Acid/Alkali Strengths Public pH • pH is a logarithmic scale – its determined by the number of H+ and OH - ions present H+ NO3 – Nitric Acid or HNO3 Na + OH - Caustic or NaOH • Each unit of increase represents an increase of 10 fold. • In terms of concentration, a pH change from 9 to 10 represents an increase of 10 times. • pH is not a measure of concentration but a condition of alkalinity or acidity and cannot be used to control concentration. Public pH • The pH scale is used to quantify the chemical characteristic of a solution which is either acidic, alkaline, or neutral but not the concentration of the solution (ounces/gallon) – test kit. • Similar to a Hot or Cold condition • We can determine that a solution is hot or cold by how it feels but we don’t know how hot or how cold until we measure it thermometer. Public The pH Scale Public pH versus Strength of Acids or Alkalis • What determines strength of an acid or alkali • Acids and alkali’s dissociate (dissolve) into solution differently. This is why some acids and alkali’s are stronger than others • Nitric Acid is stronger than phosphoric acid • Caustic is stronger than sodium carbonate Public pH • Dissociation or dissolving rates into solution determine the strengths of Acids and Alkali’s • The greater the dissociation rate the stronger the chemical • Nitric acid is stronger than phosphoric acid • Nitric acid is a better H+ donor Public Acid Dissociation Rate versus pH & Concentration Delaval Cleaning Solutions’ Acid Examples • Citric Acid – Tame NFNC • Phosphoric Acid – Maxid NF/Maxid Plus • Sulfamic Acid - Sulfam Weak to Stong • Nitric – Membrane Acid 100 • Sulfuric Acid – Hi Temp Acid 2000 (Blend of Phos, Nitric, Sulfuric) • (Note: Both Citric & Nitric can be used for Passivation Purposes) Public Alkaline Dissociation Rate versus pH & Concentration • pH is not a measure of detergent concentration, or cleaning ability • Knowing the pH does not tell us the concentration • Caustic is stronger than soda ash Public Agenda •Soils & Detergents Public Detergent Selection – What to Consider? When selecting a detergent the first thing we need to consider is the soil we are attempting to clean: Fats, Proteins, Oils, Mineral etc.. Type of surface or equipment requiring cleaning Membrane System Stainless Steel Soft Metal What is the application CIP? Foam Manual Public Soil Characteristics need to be considered when selecting a detergent • Fats: • Melt at elevated temperatures • Solidify at cooler temperatures and will stick to surfaces • Mineral: • Acids are most effective • Proteins: • At high temperatures, denature and adhere tenaciously to surfaces • May build up in layers making it more difficult to remove Public Chemical Detergents Why do we clean with detergents? Because water cannot remove oils, fats or mineral soils by itself There are primarily five groups of detergents that will break down fats, oils, proteins & inorganic (mineral) films • Alkaline cleaners: • Acid cleaners: • Solvent/degreaser cleaners: • Chlorinated alkaline cleaners: • Enzyme cleaners: Public Alkaline Detergents • Purpose: • Remove organic soils • Breakdown fats and proteins • Fats and oils: • Water insoluble • Low melting point • Hydrolyzed – make soluble with Alkali – caustic • Proteins: • Insoluble hot • Less soluble in hard water • Effectively attacked & removed by chlorine and high pH solutions Public Saponification – Solubilizing Fat (Making “Soap”) Public Soils - Fat • Saponification = Fat Breakdown • Butterfat is insoluble and will not dissolve in pure water ADD CAUSTIC & WA LA!! • High alkalinity coupled with heat increases the solubility of the fat helping to dissolve it • Surfactants in the detergent would even improve soil removal Public Soap in Hard Water = Film (Milkstone/Soap Scum) Public Soils - Protein • Denaturing – Losing Strength • High Alkalinity will also denature protein Public Soils – Protein (cont.) • Thin protein residues can be recognized by their rainbow-like color • Chlorinated products work well at removing protein soil Public Agenda •Alkalinity/Alkaline Detergents Public Alkalinity • Is the measure of the quantity or actual amount of alkali present in the solution • A solution with a ph > 7 is considered alkaline • Is determined by the amount of hydroxide OH ions present (NaOH) • Not to be confused with pH. Two different alkali’s at equal concentration can have vastly different pH values Public Alkalinity (cont.) • Alkalinity is measured in several ways • The alkalinity of a solution is typically composed three components • Total Alkalinity • Inactive Alkalinity • Active Alkalinity Public Alkalinity (cont.) • Inactive alkalinity - the alkaline component found natural in the water sample • Typically low alkalinity value – 1 to 3 drops • Test the alkalinity to determine this part and for establishing a blank • Contributes nothing towards cleaning but can affect results if not considered Public Alkalinity (cont.) • Active Alkalinity – the active chemical portion of the cleaner • That portion represented by the chemical contribution • Active alkalinity is the portion that exists above a pH of 8.4 or that portion above the inactive alkalinity • 8.4 is the pH level at which phenothalien alkalinity indicator turns pink • It is the portion that is largely responsible for cleaning effectiveness Public Alkalinity (cont.) • Total alkalinity – the sum of active and inactive alkalinity • Includes the total alkaline constituents in the solutions including the inactive alkalinity in the water • This is why we choose to run a blank on the water being mixed with the cleaner, then adjust the target concentration accordingly Public Cleaning With Detergent – Alkaline’s Alkaline Cleaners: • Many sources of alkalinity may be used in a single cleaner: • Sodium hydroxide – caustic • Potassium hydroxide – caustic potash • Sodium carbonate • Sodium metasilicate Public Alkaline Detergents • Types of common alkaline detergents: • Caustics – NaOH 50%, KOH 45% • “Built” caustics may contain: • Chelates, surfactants, De Foamers, rinse aids • Silicates/Carbonates – sodium • Above products may or may not contain chlorine – chlorinated alkaline CIP Cleaners Public Alkaline Detergents (cont.) • Typical High Alkaline Uses: • Caustics: NaOH, KOH • Aggressive cleaning situations • Fryers, Evaporators, Chad Cabinets, HTST Systems, Separators • More dangerous to handle • High temperature cleaning situations • All stainless steel systems Public Chlorinated Alkaline CIP Detergents • Application Uses • Lower levels of NaOH or KOH<20% • Chlorine added • Less aggressive cleaning situations • Lower temperature cleaning situations • Requires all stainless steel equipment systems Public Chlorinated Alkaline Foaming Detergents • Application Uses • Silicates/carbonates compounds • Less aggressive cleaning situations • USFD manual for foam cleaning purposes • Lower temperature cleaning situations • Still requires all stainless steel equipment systems if chlorinated Public Agenda •Acidity/Acid Detergents Public Cleaning With Detergent - Acids Acid Cleaners: • Acid cleaners today are typically a blend of Nitric and Phosphoric acid • They are designed to remove mineral soils & milkstone films • Surfactants are not compatible in high Nitric acids Public Acidity • When you measure acidity, you are measuring the amount of acid present • A solution with a pH<7 is considered acidic • Acidity refers to the amount of hydrogen H+ ions present in the solution • Not to be confused with pH, two different acids at equal concentration can have vastly different pH values Public Acid Detergents • Purpose: • Primarily to remove mineral soils (milkstone – inorganic) • Organics (proteins and fats) • Brighten stainless steel • Bacteriostatic condition (pH<3) Public Soils - Minerals • High levels of acidity will dissolve mineral salts Public Milkstone Public Acid Detergents • Categories of Acid Cleaners • Hydrofluric– specialized • Sulfuric – very strong • Nitric – Strong • Phosphoric – moderate strength • Citric/Sulfamic – Mild Public Acid Detergents (cont.) • Characteristics: • Hydrofluric – (strong) • Special applications and concerns • Main purpose for removal of silicate films • Most desirable temperature of use is cold to 140 degrees F • Is corrosive and can burn stainless steel • Dangerous to use and must be used with proper PPE • Restriction of use Public Acid Detergents (cont.) • Characteristics: (H2SO4) • Sulfuric acid – (very strong): • Use for aggressive CIP cleaning situations only • Use below 160 degrees F and only on stainless steel • Don’t use if barium is present in water supply • Is highly corrosive and can burn stainless steel • Will attack surfactants and most gasket materials • Use today primarily for pit control of effluents Public Acid Detergents (cont.) • Characteristics: (HNO3) • Nitric acid – (strong) • Most commonly used acid today • Economical in cost • Use for aggressive CIP cleaning situations only • Use below 160 degrees F and only on stainless steel • Non-corrosive to stainless steel as a liquid • Used to passivate stainless steel • Does not shine surfaces as well as phosphoric • Will attack gaskets and green scrub pads Public Acid Detergents (cont.) • Characteristics: • Phosphoric acid – (moderate): (H3PO4) • Circulation, foam, and manual cleaning systems • Good choice in blends & reclaim systems • Most desirable temperature of use is 140 to 155 degrees F • More expensive to use • Non-corrosive to stainless steel • Does not attack surfactants and can be used with scrub pads • Provides bright shine on stainless steel surface Public Acid Detergents (cont.) • Characteristics: • Sulfamics – (weak) • Circulation and manual cleaning systems • Most desirable temperature of use is 140 to 155 degrees F • Non-corrosive to stainless steel and non stainless metals • Does not attack surfactants and can be used with scrub pads • Has little to no effect on most gasket materials • Special Applications • Sulfamic/Oxaylic – de-staining, descaling Public Agenda •Chlorinated Detergents Public Chlorine Detergents • Most effective on protein soils • Very inexpensive to use • Strong oxidizer • Becoming an increasing environmental concern • Highly corrosive to stainless steel (increases with exposure time and concentration) • Used in circulation and manual cleaning systems • Not compatible with some surfactants Public Chlorine Detergents • Blended with alkali’s to provide dual purpose cleaning: • Alkaline wash and sanitizer • Effective cleaning and time saving • But not a sanitizer or disinfectant • Common applications: • Pre-built circulation cleaner • Pre-built manual and foam cleaning application Public Chlorine Detergents • Note – Never combine with Acid Detergents!!! Public Questions o Preguntas? Public
