Cleaning and disinfection

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Cleaning and Disinfection - C&D

BASIC INFORMATION

C&D are used to minimize secondary contamination of raw materials, byproducts or

products

Important aspects of C&D are: the purposes and staff awareness

Staff must be trained

C&D are applied according to instructions and recorded

Effectiveness of C&D have to be confirmed by laboratory tests (swabs from

machines, tools and surfaces) and recorded

Manual tools and small devices used to keep cleanliness have to be stored in dry and

clean place

Applied chemical agents have to be certified to application in food industry

List of C&D agents used has to be recorded

Instructions describing C&D procedures should consider specific chemical agent

C&D tools, machines and chemical agents have to be stored in separate utility room

REMEMBER

: C&D tools and machines have to be kept clean

What is the first step in a cleaning and disinfection program?

The first step in any cleaning and disinfection program is cleaning. Cleaning is the

removal of organic material (i.e., manure, blood, feed, and carcasses). It is important to
remove these organic materials before the disinfection process begins because disease
agents are often protected in these materials and can survive the disinfection process. Hence,
it is important to thoroughly clean a building before the disinfection process. The cleaning
process can include a dry cleaning and a wet cleaning step.

What are the differences between dry cleaning and wet cleaning?

Dry cleaning involves the physical removal of organic material, such as the removal of feed,
litter, and manure. The process of dry cleaning physically removes the organic material
before the actual wet cleaning can occur. Wet cleaning, as its name implies, involves the use
of water.

There are four basic steps in the wet cleaning process:

 soaking
 washing
 rinsing
 drying

Although not necessary, detergents (wetting agents) can be used in the wet cleaning

process. However, it is more important to have pressure washers with the proper pressure
(35-55 atm) to ensure all the organic materials are removed from the facilities. The final
step of ensuring a proper clean-up is having the wet areas of the building dried quickly. If
the building is not dried properly, the excess moisture can result in bacteria multiplying to
higher levels than seen before cleaning. Thus, if you are going to clean, make sure the
cleaning procedure is done properly, as an improper cleaning can actually do more harm
than good! If done properly, a good cleaning can remove 90% of the pathogens.

Cleaning and disinfection

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What are the main types of disinfectants that can be used?

The main types of disinfectants that can be used are:

• aldehydes (i.e., formalin, formaldehyde, and glutaraldehyde)
• chlorine-releasing agents (i.e., sodium hypochlorite, chlorine dioxide, sodium

dichloroisocyanurate, and chloramine-T)

• iodophors (i.e., povidone-iodine and poloxamer-iodine)
• phenols and bis-phenols (i.e., triclosan and hexachlorophene)
• quaternary ammonium compounds
• peroxygens (i.e., hydrogen peroxide and peracetic acid)

PRINCIPLES OF CLEANING AND DISINFECTION

1. BASIC STEPS IN CLEANING AND DISINFECTION

a) Remove gross and loose dirt.
b) Bring detergent into contact with dirt by wetting.
c) Allow time for the agent to disperse, break down and emulsify the different

components of the dirt (fat, protein and mineral deposit).

d) Rinse away dispersed dirt and traces of detergent (whilst preventing cross

contamination of clean surfaces).

e) Apply disinfectant to kill remaining virus particles.
f) Rinse away residues of disinfectant.

2. CLEANING

It is essential to clean surfaces before they are disinfected as disinfectants are inactive

in the presence of organic matter

2.1 WATER

a) Water is important in cleaning because it:

• acts as the solvent for the cleaning and disinfectant compounds
• wets the surface to be cleaned
• removes dirt
• rinses off any residues of the cleaning and disinfectant compounds.

b) The hardness of the water (determined by the amount of calcium salts dissolved in it) is

an important consideration in deciding the most suitable cleaning agent and the
amount to be used.

2.2 DIRT

a) The amount of dirt on the surface and its composition will affect the degree of physical

and mechanical action required to remove it.

b) Its interaction with the material of the equipment, the degree of penetration into the

surface of the equipment and the equipment design (and thus accessibility of the
surfaces for cleaning) are important factors in the effectiveness of cleaning.

c) Material from animal carcasses, which contain high levels of protein and fat, must be

removed using moderately warm (not hot) water to avoid caking or coagulation

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2.3 CLEANING AGENTS

Cleaning agents:

• act as wetting agents, lowering the surface tension of water, thereby improving the

agent’s ability to contact and penetrate the surface to be cleaned

• emulsify oils and fats, facilitating their subsequent removal by physical or

mechanical means

• help disperse dirts causing break down into smaller particles which are more easily

removed

• assist in the breakdown of protein deposits by chemical action into peptides, which are
more soluble and more easily removed than the protein compounds.

2.4 CLEANING PERFORMANCE

The efficiency of cleaning depends on:

• Mechanical action – the greater the better – consistent with not damaging

equipment

• Concentration of the cleaning action – manufacturers recommendations must be

followed

• Temperature – generally the higher the temperature the better (up to 80°C) –

especially with fatty deposits

• Contact time – sufficient time must be allowed for the agent to work.

Detaching dirt particles is crucial to get expected microbiological cleanliness

level

Bacteria locate on surface through electrostatic forces
on distance – 2 – 20 nm.
Dirt particles locate much higher – 20 - 50 nm through Van der Waals forces.
It means dirt particles protect microbes against disinfection agents

Removing dirt enables access disinfectant agent

to target – superficial microbes layer

REMOVING DIRT CONSISTS OF:

emulsifying proteins and fat particles what enable solving it and removing with
water

fat saponification

destroying huge aggregates of dirt particles and converting them into easy
washable soles

complexation of calcium and magnesium ions, dispersing dirt particles in solution

moving away mineral contaminants by applying acidic agent

FORMS OF CLEANING AGENTS

solution – basic, neutral, acidic

foams - basic, acidic

gels – with detergents and/or basic agent

Big surface, walls, ceilings, floors – foams and gels
Applied on walls last several minutes (foams) or some hours (gels) – higher effectiveness

Foam is produced by aeration of cleaning agent. Consists of huge numbers of small

air-bladders which walls is detergent cleaning agent. After applying on surface air-bladders
successively brake and moisten with cleaning agent

Cleaning and disinfection

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TYPICAL FOAM COMPOSITION

1 liter of cleaning agent
49 liters of water
450 liters of air

make

500 liters of foam

The amount of 500 L of foam is enough to cover 200 m

2

2 mm thick layer

The yield for manual cleaning does not exceed 30 m

2

ADVANTAGES OF FOAM CLEANSING

Hygienic aspects:

lack of aerosols spreading bacteria and contaminants

prolonged touch time with cleansing surface

Convenience of service

decreasing of cleansing time

using simplicity

elimination expose people to concentrated cleaning agent

ECONOMICAL ASPECTS:

decreasing exposure of machines and tools to corrosive agents

economizing on energy and water

THE EFFECTIVENESS OF C&D PROCESSES DEPENDS ON:

proper sanitary and technical condition of work surfaces, walls, floors,

correctly used materials to construct machines, tools, (stainless steel, synthetic
materials)

applying suitable cleaning agents and disinfectants, theirs concentration, pH, time or
reaction, temperature, hardness number of water

choice suitable disinfection method

applied proper cleaning machines

CLEANING METHODS

manual or semiautomatic in system COP (Cleaning Out of Place) used to clean open
surfaces such as tables, walls, machines after disassembling,

automatic in system CIP (Cleaning In Place) in individual machines or closed
installations. Circulation closed cleaning is the most effective as well as the most
expensive

GOOD CLEANING AGENT SHOULD:

 express high coefficient spreading – ability to moisten surface
 express high ability to emulsify and disperse fat (keep fat droplets in dispersed form)
 saponificate fats
 cause expanding and colloidal dispersion of proteins
 dissolve organic and inorganic contaminants
 rinse contaminant form dirty surface
 prevent secondary creation sediment

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 form solving complexes with components increasing hardeness of water
 express ability to penetrate dirt
 be easily removable during rinsing

Properly provided cleaning could reduce number of microorganisms by 5 orders of
magnitude but combined with disinfection even by 8 order

99,999999%

Disinfection could be applied only after cleaning and rinsing detergents

Sometimes in modern agents both at the same time

C&D:

– quite separate processes
– must not be applied at the same time.

GOOD DISINFECTANT FEATURES:

High bactericidal, viricidal and fungicidal effectiveness

Durability

Fast effectiveness

Low concentration of working solutions

Stability of work solutions

Low toxicity for human

Low toxicity for environment

Safe for worker

Effectiveness can not be decreased by

 Presence of organic compounds
 pH
 relative humidity
 presence of soaps and detergents
 high hardness water
 other environmental, chemical or physical agents

Low toxicity for animals

Cheap and easy to use

Easy to rinse from any surface

Biodegradable

Does not cause allergy

Does not cause abrasive and colour changes

Odorless

FREQUENTLY MADE MISTAKES DURING DISINFECTION

• insufficient cleaning before disinfection
• ineffective disinfectant
• low concentration of disinfectant
• too short a time of disinfection
• too cold or too warm disinfectant solution
• gas disinfection at too low relative humidity
• insufficient rinsing detergents before disinfection – disinfectant inhibition by

soap, detergents improper pH

• ignoring disinfectant inhibition by plastics
• using water of too high hardness

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• bacterial surface contamination during rinsing with water of low microbiological

quality

DOCUMENTS –

RECORDS OF CLEANING AND DISINFECTION SHOULD

INCLUDE:

name of worker responsible for treatments,

frequency of treatments

name of detergent – disinfectant, concentration, temperature

methods of treatments

Verification of cleaning and disinfection:

 evaluation of physical cleanliness
 evaluation of chemical cleanliness
 evaluation of microbiological quality of disinfected objects

EVALUATION OF CLEANLINESS PRIOR TO PRODUCTION

physical - visual

microbiology:

- on the base of analyses of cleaning and disinfection parameters records
- microbiological tests, luminometry (ATP estimation)

chemical:

- on the base of analyses of records
- pH analyses of washings after end rinsing