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Cleaning and disinfection
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.
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Cleaning and disinfection
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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Cleaning and disinfection
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
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Cleaning and disinfection
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 m2 2 mm thick layer
The yield for manual cleaning does not exceed 30 m2
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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Cleaning and disinfection
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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Cleaning and disinfection
" 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