6. Cleaning and Cleaning Agents Flashcards
Definition of cleaning
Removal of soil, dust, organic matter, microorganisms from facilities w/ detergents or abrasive cleaners
Characteristics of cleaning
- Mechanical/physical pre-cleaning is important for sanitation program
- Cleaning prior to disinfection increases disinfectant efficacy and log reduction
- Cleaning agents intended for SPECIFIC AREAS
- may REMOVE significant no of microbes, BUT NOT DESIGNED TO KILL/ELIMINATE
Factors that affect cleaning performance (TACT WINS)
TIME contact time
ACTION physical force exerted/mechanical energy applied
CONCENTRATION amount of cleaner used
TEMPERATURE amt of energy (heat) in the cleaning sol
WATER prepare cleaning sol
INDIVIDUAL worker performing clean up operation
NATURE composition of soil
SURFACE what material is being handled
Function of cleaning compounds
To lower surface tension of water, so soils are loosened and flushed away
- sequestering
- wetting
- emulsification & suspension
- dissolving
- saponification
- dispersion
- peptizing
- rinsing activity
Characteristic of ideal cleaning compounds
- economical
- non toxic
- non corrosive
- non caking
- non dusting
- easy to measure/meter
- stable during storage
- easily and completely dissolve
Classification of cleaning compounds
- alkaline
- acid
- synthetic detergents
Alkaline cleaning compounds
STRONG
NaOH, silicate
HEAVY DUTY
Na-metasilicate, Na-hexametaphosphate, Na-pyrophosphate, Na-carbonate, Trisodium phosphate
MILD
Na-carbonate, Na-sesquicarbonate, Tetrasodium pyrophosphate, phosphate water conditioners (sequesters), alkyl aryl sulfonate (surfactant)
CHLORINATED
HYPOCHLORITE added to peptize proteins for easier removal; well adapted for CIP of pipes, tanks, vats; remove effectively fat, oil, grease, proteins
Acid cleaning compounds
STRONG
hydrochlroric, hydrofluoric, sulfamic, sulfuric, phosphoric acids
MILD
levulinic, hydroxyacetic, acetic and gluconic acids
Synthetic detergents
Most effective to lower surface tension of solution, promoting wetting of particles, deflocculating and suspending soil particles
General structure of detergents
Q- X(-)M(+)
Q: hydrophobic portion, hydrocarbon chain CnH(2n-1)
X-: anionic/hydrophilic portion
M+: countrer ion in solution
Detergent classification
- Anionic (negative)
- Cationic (positive)
- Nonionic (neutral)
- Amphoteric (pH dependent)
Principles of detergents/surfactants action
- Detergent enables water to wet object thoroughly
- Hydrophobic tails of detergent anions dissolve in grease
- Water molecules attract hydrophilic heads of detergent anions, lifting up grease
- By stirring, grease forms tiny droplets. forming emulsion
Anionic surfactants
When reacted with hard water, forms deposit
Low solubility in cold water
e.g. alkyl sulphate, alkyl benzene sulfonate, Na lauryl sulphate
Cationic surfactants
Also possess antimicrobial characteristics
e.g. Dimethyl-dodecyl-benzalkoniumchloride
Acid anionic detergent
- Anionic surfactant + acid
- Organic acids (acetic, peroxyacetic, lactic, propionic, formic)
- Stable, long shelf life
- Non corrosive, non staining, low odor
- Not affected by hard water
- Removes and controls mineral films
- High foaming but nonfoaming ones are available
- Skin irritant
Carboxylic acid anionic detergent
- FA + organic acids + mineral acid
- Low foaming CIP application
- Broad spectrum
- Stable, good shelf life
- not affected by hard water
- Removes and controls mineral films
- Non staining
Non ionic surfactants
- Undissociated in sol
- Strong emulsifier
- Not affected by hard water
- Highly soluble in water (liquid detergent)
- turns turbid when exposed to heat
e.g. alcohol soluble etoxylate;
nonil phenol etoxylate; polyglycol ether, polyglycol amide
Amphoteric surfactants
- Positive (cationic) or negative (anionic) charge depending on pH of sol
- basic structure R-NH-CH2-COOH
e.g. dodecyl diamino ethyl glycine
What are sequestrants/chelating agents
Additives used in cleaning compounds to prevent hardness constituents and salts of Ca and Mg from depositing on equipment surfaces by binding of these salts to their molecular structure or binding of other ions
Examples of sequestrants/chelating agents
- Na polyphosphates
- EDTA : may be used in conveyor lubricant formulations
- TSPP : Tetra sodium pyrophosphate
- TPP : Tetra potasium pyrophosphate
- NTA : Nitrile triacetic acid
- Na tripolyphosphate and Na tetraphosphate (Quadrofos)
- Na hexametaphosphate (CALGON)
- Sodium salts: gluconic and heptonic acid
Five steps in cleaning and sanitation methods
- Dry/physical cleaning
- Pre rinsing
- Detergent application
- Post rinsing
- Sanitation
Foam cleaning
- Foam detergent, large SA
- 25m2/min, 10-20min
- Rinse w water and bactericidal compounds
- Easy, wide coverage SA
Applicatons: transport equipments, ceiling. walls, pipelines, belts, storage containers
Gel cleaning
- Gel tightly attached on moving parts, no splashing
- Req high pressure portable unit
Applications: food packaging equipment
Clean out of Place (COP)
Manual cleaning: 3 tank system
- Equipment rinsed under tapwater
- Placed in tank I (with DETERGENT) and soaked
- Trf to tank II (with DETERGENT) and brushed(?)
- RINSED w hot water, trf to tank III for sanitation (77C 1.5min + disinfectant)
- Rinsed to get rid of disinfectant, draining
APPLICABLE FOR: small equipments, auxiliary materials
Clean in Place (CIP)
- For large/difficult to assemble equipments or pipes in situ
- Close circuit system
- Liquid food industries
- Common equipment: pipes, tank, heat exchanger, centrifuge machines, homogenizer
- TURBULENT flow
CIP mechanism
- Preliminary rinse (hot/cold water) to remove gross soil
- Detergent wash
- Rinse to remove residual soil and cleaning compounds
- Sanitize to destroy residual microbes
- Final rinse to remove CIP solutions and sanitizers
CIP systems
- single use
- reuse
- multiuse
Single use CIP
- use cleaning sol once
- minimize cross contam
- optimize cleaning sol
- portable
Reuse CIP
- recover and reuse cleaning compounds and cleaning sol
- Contam of cleaning minimal (soil removed during prerinse cycle)
- PARTS: acid tank. alkaline tank, freshwater tank, return water tank, heating system. CIP feed, return pumps
Multiuse CIP
- Combination of single use and reuse system
- for pipelines, tanks, and other storage equipments
- AUTOMATICALLY CONTROLLED PROGRAMS entail various combinations of cleaning sequences w circulation of water, alkaline cleaners, acid cleaners and acidified rinses
New mechanical cleaning methods
- Ultrasound
- Ice pigging
- Pulsing flow
- Two phase
Ultrasound cleaning
- sound waves w freq > 20kHz
- for glass tubing, membranes and metal, glass, ceramic and plastic surfaces
- more effective when combined w heat, pressure, nonfoaming enzymes
Adv and disadv of ultrasound
ADV
- effective in cleaning surfaces, dismantled and/or small items
- clean conveyor belts better
DISADV
- may disperse organisms outside treatment area
What is ice pigging
- Ice pig slug formed by stable ice slurry combined w/ freezing point depressant
- pumped through range of pipes with good degree of sweeping
- capable of cleaning in ductwork and/or separating product in different phases, pipe fittings, with good degree of sweeping
- removes “soft” fouling (in jam, ketchup or fat production)
Adv and disadv of ice pigging
ADV
- better than conventional solid pigs
- low environmental impact
- never gets stuck in for pipework for a long time (melts)
DISADV
- needs CIP to ensure proper cleaning
What is pulsing flow
- Imposing velocity pulse over steady flow to increase local shear rate and pressure at the deposit
- Cosed systems where liquid is too viscous to achieve turbulent flow
- Frequency and amplitude are important parameters
Adv and disadv of pusling flow
ADV
- attractive for systems where liquid is too viscous
- shorten cleaning time
DISADV
- difficult to remove soil in areas difficult to clean
- additional research is needed
What is two phase cleaning
Increasing effectiveness of cleaning by permitting air to leak into vacuum of systems
Adv and disadv of two phase cleaning
ADV
- Reduce water req for circulation
DISADV
- More research required
Criteria for eco-friendly cleaning agents
- 60-70% BIODEGRADABLE within 28 days for organic components above 1% in the ready to use product
- NON HAZARDOUS WASTE
- LOW ORAL LETHAL DOSE
- Environmental hazard: no phenolic compounds, petroleum solvents or heavy metals
6 Green Attributes
- Do not cause skin irritation
- Air pollution potential: no VOCs
- No fragrances
- No dyes
- Packaging: reduced and recyclable
- Include features to minimize exposure to concentrate
