cleaning & disinfection 2
TRANSCRIPT
8/8/2019 Cleaning & Disinfection 2
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Cleaning & Disinfection 2
FOOD TECHNOLOGY, HYGIENE & SAFETY (DEMT 2333)
DIPLOMA IN ENVIRONMENTAL HEALTH VICTORIA INTERNATIONAL COLLEGE
BY: MR KHAIRUL NIZAM MOHD ISA DEPARTMENT OF ENVIRONMENTAL HEALTH
8/8/2019 Cleaning & Disinfection 2
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OBJECTIVES
Study the important principles apply to the process of cleaning
and disinfection
Study variety methods of disinfection
Study the procedure of cleaning and disinfection
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DISINFECTION
Cleaning remove large number of micro-organism but not kill
them. Therefore vehicle of contamination in food premises.
Using:
heat
chemicals
irradiation (UV) ± for atmospheres, clear water but not for
surfaces
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Heat disinfection
Effective but may be not practicable for surfaces
Use in machines e.g. dishwashing, 88°C, contact times 1-15
seconds
Sterilizing unit, 82°C for 30 seconds
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Steam disinfection
Steam jets to disinfect machinery or surfaces (difficult to
reach)
Self drying but disadvantages :
effect on some materials, wall, ceiling, paint,
remove grease and lubricants from machinery,
safety hazard (for untrained workers),
form condensate on other equipment (overhead pipes &
metal girders)
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Chemical disinfection
Care taken to avoid effect on food, equipment or personnel
1. Chlorine-release agent
hypochlorus acid (HOCL) - disinfect by oxidation of protein
2,000 ppm., 3 mins.
use below 40°C to corrosion. Maximum 200 ppm,
contact time 20 min.
Upon completion of disinfection rinsed off with clean,
cold water.
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2. Quaternary ammonium compounds (QAC)
Safe, odour-free, non-corrosive, stable and taint-free
bactericides.
Not effective against Gram-negative bacteria, viruses, fungi
Cationic ± in brewing, fermentation
3. Iodophors
Expensive, consisting of I2 + non-ionic surfactant in an acid
medium.
Suitable for dairy, breweries, soft drink industry Advantages: ability to kill a wide range of organisms,
effective at low temp, tolerance of soiling and hard water
and brief contact time.
Not use on Al or copper, plastic (stain)
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4. Biguanides
Bactericidal in acid; expensive
Similar to QACs, but better all round performance.
Use in glass washing.
Not suitable in highly alkaline condition and use after
caustics.
5. Amphoteric surfactants
Bactericidal properties in acid solution.
Low toxicity, relatively non-corrosive, tasteless andodorless.
Good detergent but expensive and limited antibacterial
activity.
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6. Peroxy compounds
Terminal disinfection in large dairies
Paretic, replace hydrogen peroxide - detergent blend
7. Paretic acid
Acid, oxidative action, suitable only on glass or stainless
steel
8. Alcohols
³dry´ area e.g. point of sale, packing belts spray/wipe.
Blend with QAC, mild detergent e.g. Ethanol, iso- propanol
9. Aldehydes
Formaldehyde and glutaraldehyde have a wide spectrum but
high toxicity and irritancy characteristics.
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Choice of disinfectant
Amount of soiling
Water hardness
Contact-time
Type of micro-organism
Type of surface to be disinfected
Possibility of taint
Temperature
Toxicity of disinfectant and effect on personnel
Ionic nature of detergent before disinfection
Ways its used/method of application
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Where to disinfect
Direct food ± contact surface
Hand-contact surface
Food worker¶s hands
Cleaning materials of equipment ± cloth towels at 65°c
washing machine
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Control procedures
1. Visual indicator e.g. iodophor
2. Bacteria-swabbing of surfaces
3. Examination of food product
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PR OCEDUR ES AND METHODS OF CLEANING
1. Pre-clean: sweeping, wiping, scrapping off, pre-rinsing/pre-
soaking
2. Main clean: apply detergent and loosen dirt
3. Immediate rinse: remove loosened dirt, chemical
neutralization of cleaning agent
4. Disinfection: destruction of residual micro-organism
5. Final rinse: remove disinfectant residues
6. Drying: remove final rinse water
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Cleaning methods
Soaking
Manual cleaning
Pressure washing
Use foams, gels or mist
CIP
Machine dish washing
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Clean-in-place (CIP) equipment
CIP replace hand cleaning in dairies, breweries and potable
liquid installations
Circulating non-foaming detergents and disinfectants through
equipment
Combined effect off
Without dismantling and manual cleaning
Turbulence
Chemicals
Heat
High turbulence Low turbulence
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5 steps of basic CIP
Pre-rinse with cold water to remove grass soil
Detergent circulation to remove residual debris and scale
Immediate rinse with cold water to remove traces of
detergent
Disinfectant circulation to destroy micro-organisms
Final rinse with cold water to remove traces of disinfectant