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



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



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



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



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)



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.



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)



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.



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.



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



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



Control procedures

1. Visual indicator e.g. iodophor

2. Bacteria-swabbing of surfaces

3. Examination of food product



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



Cleaning methods

Soaking

Manual cleaning

Pressure washing

Use foams, gels or mist

CIP

Machine dish washing



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



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



Thank You

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