Techniques used in dairy industry

1. Current Cleaning Techniques in
Dairy Processing Industry
By
N.SELVAPRAKASH
MTM19014
M.Tech –I year
FST-519 Advances in Milk Processing (2+1)

2. Introduction
• Cleaning is the process in which unwanted
matters including food poisoning and spoilage
microorganisms are removed to prevent
contamination of products.
• Sanitization reduces the microbial load of cleaned
surface to a level,which is considered to be safe
for handling and processing of dairy and food
products.
• Cleaning without sanitization is meaningless.
• Both terms are complementary and
supplementary to each other.

3. • Milk stone: It is the deposition of milk solids,
water hardness compounds and washing
solutions on the surface due to heating.
• It normally consists of precipitated ,
coagulated and heat dried milk proteins and
insoluble calcium salts from water and
detergent solutions.

4. Importance of Cleaning
• Should be properly cleaned because of milk as
excellence source of microbes.
• Chemicals, detergents should not affect the
equipments.
• Cleaning and Sanitizing is complementary
processes
• Clean milk production.

5. Objectives of Cleaning
• Physical cleanliness – removal of all visible dirt
from the surface
• Chemical cleanliness – removal not only of all
visible dirt but also of microscopic residues that
can be detected by taste or smell but are not
visible to the naked eye
• Bacteriological cleanliness – attained by
disinfection
• Sterile cleanliness – destruction of all
microorganisms

6. Cleaning Procedures
• Cleaning of dairy equipment was formerly
done (and still is in some places) by people
armed with brushes and detergent solutions,
who had to dismantle equipment and enter
tanks to get to the surfaces.
• This was not only laborious but also
ineffective;
• products were often re-infected from
imperfectly cleaned equipment.

7. CIP
• Circulatory cleaning-in-place (CIP) systems
adapted to the various parts of a processing plant
have been developed to achieve good cleaning
and sanitation results.
• Cleaning operations must be performed strictly
according to a carefully worked out procedure in
order to attain the required degree of cleanliness.
• This means that the sequence must be exactly the
same every time.

8. Cleaning cycle
• Recovery of product residues by scraping,
drainage and expulsion with water or
compressed air
• Pre-rinsing with water to remove loose dirt
• Cleaning with detergent
• Rinsing with clean water
• Disinfection by heating or with chemical agents
(optional); if this step is included, the cycle ends
with a final rinse, if the water quality is good.

9. Component on
surface Solubility
Ease of removal
Low/medium
pasteurization
High
pasteurization/UHT
Sugar Water soluble Easy
Caramelization, more
difficult to clean
Fat
Water insoluble,
Alkali soluble Easy to difficult
Polymerization, more
difficult to clean
Proteins
Water insoluble,
Alkali soluble,
Slightly in acid Difficult
Denaturation Very
difficult
Mineral salts
Water solubility varies
Most salts are acid
soluble Varies Varies

10. PRE-RINSING WITH WATER
• Should be carried out immediately after the
production run.
• Otherwise, the milk residues will dry and stick to
the surfaces.
• Milk fat residues are more easily flushed out if the
pre-rinsing water is warm, but the temperature
should not exceed 55 °C, to avoid coagulation of
proteins.
• Must continue until the water leaving the system
is clear, as any loose dirt left will increase
detergent consumption.

11. Cleaning with Chemicals
• Usually washed off with alkaline and acid
detergents.
• The detergent must also be capable
of dispersing dirt and encapsulating the
suspended particles to prevent flocculation.
• Polyphosphates are effective emulsifying and
dispersing agents that also soften water.
• The most commonly used are sodium
triphosphate and complex phosphate compounds.

12. • Chemicals are used in sanitation procedures
for two principal reason
1. To change soil so as chemically to soften,
disperse, or dissolve it.
2. To destroy the viability of microorganisms.
These chemicals are either detergents or sterilants

13. Alkaline detergents
• These are generally available and economical.
• The more common of these are sodium
hydroxide or caustic soda (NaOH); sodium
bicarbonate, (NaHCO3); sodium carbonate or
soda ash (Na2CO3); sodium sesquicarbonate
(Na2CO3 ·NaHCO3 ·2H2O), and trisodium
phosphate (Na3PO4 ·12H2O).

14. Acids
• Acids have come into increasing use as dairy
detergents.
• They are generally used in weak solutions of
about 0.1 % or slightly more.
• Those more commonly used are phosphoric
and nitric acids

15. CIP CIRCUITS
• CIP programmes for circuits with pasteurizers
and other equipment with heated surfaces
(UHT, etc.)
• CIP programmes for circuits with pipe
systems, tanks and other process equipment
with no heated surfaces

16. CIP programme for a pasteurizer,
hot components
• Rinsing with warm water -10 minutes
• Circulation of an alkaline detergent solution – (0.5 – 1.5
%) 30 minutes at 75 °C
• Rinsing out alkaline detergent -warm water for five minutes
• Circulation of (nitric) acid solution - (0.5 – 1.0 %) for 20
minutes at 70 °C
• Post-rinsing with cold water
• Gradual cooling with cold water for about eight minutes
• Pasteurizer is disinfected in the morning, before production
starts. This is typically done by circulating hot water at 90 – 95
°C for 10 – 15 minutes after the returning temperature is at
least 85 °C.

17. CIP programme for a circuit with
pipes, tanks
• Rinsing with warm water for three minutes
• Circulation of a 0.5 – 1.5 % alkaline detergent
at 75 °C for about 10 minutes
• Rinsing with warm water for about three
minutes
• Disinfection with hot water 90 – 95 °C for five
minutes
• Gradual cooling with cold tap water for about
10 minutes (normally no cooling for tanks)

18. CIP programme for 'cold
components'
• Rinsing with water
• Circulation of alkaline detergent
• Rinsing with water
• Disinfection with hot water
• Cooling with tap water

19. Types of CIP
• Centralized cleaning
• Decentralized cleaning

20. Centralized CIP
A Milk treatment B Silo tanks C Tank gardens D Filling machines

21. Principle of the centralized CIP system
• A station of this type is usually highly automated. The tanks
have electrodes for high and low level monitoring.
• Returning of the cleaning solutions is controlled by
conductivity transmitters.
• The conductivity is proportional to the concentrations
normally used at dairy cleaning.
• At the phase of flushing with water, the concentration of
detergent solution becomes lower and lower.
• At a pre-set value, a change-over valve routes the liquid into
the drain, instead of the relevant detergent tank.
• CIP programmes are controlled from a computerized
sequence controller.
• Large CIP stations can be equipped with multiple tanks to
provide the necessary capacity.

22. Decentralized CIP
• Decentralized CIP is an attractive alternative
for large dairies, where the distance between a
centrally located CIP station and peripheral
CIP circuits would be extremely long.
• The large CIP station is replaced by a number
of smaller units located close to the various
groups of process equipment in the dairy.
• Also called Satellite CIP System.

23. DECENTRALIZED CIP
1.Storage tank for alkaline detergent 2.Storage tank for acid detergent
3.Ring lines for detergents 4.Objects to be cleaned 5.Decentralized CIP units
6.Decentralized CIP system with its own detergent tanks

24. Important Instructions for Use of
Chemicals used for cleaning
• Use of “Material Safety Data Sheet (MSDS)”:
Every detergent and sanitizer has its specific
handling requirement, depending upon their
reactive nature to users,handling equipment
and surrounding atmosphere.
• In order to prevent harmful effect and
inconveniences, one should read carefully and
go with safety instructions about the chemicals
and its necessary application techniques.

25. Selection and Handling of effective
chemicals
• Proper labelling of containers of detergents and
sanitizers
• Specifically earmarked space at safe distance from
processing areas to prevent cross-contamination of milk
and milk products.
• Availability of proper chemical handling means like
hand gloves, safety shoes etc. in the storage vicinity.
• Adequate training to personnel handling these
chemicals.
• The containers of these chemicals should be placed
over pallets of suitable materials like plastic.
• Enough lights should be provided in the storage area.
• Proper display of precautions in handling

26. Cleaning and sanitization of Milk Cans
and Tankers
• Types of Washers
• Manual washing: Small plants are not
equipped with mechanical can washers and
employ manual washing methods.
• Manual washing can be aided by installation
of can washing trough, can scrubber, and can
rinsing and steaming block.

27. Mechanical washer
• In mechanical washing, the can is usually
passed over a succession of jets emitting water,
cleaning solution, hot water, steam and air.
• Where the operation is big and manual
washing is considered difficult and
uneconomical, washing is done mechanically.
• 2 types are there
• Straight through or tunnel type
• Rotary type

28. Rotary type
• One man is required to place the cans and lids in
inverted position in the machine and remove them
after washing and drying.
• The can and lid are moved through a rotating
platform divided into sections.
• A series of tanks of solutions are located under the
platform.
• Cans get continuous spray of various solutions
both inside and outside through circulating pumps
and solutions return to respective tanks.
• The rotary washer rotates at intervals.

30. Straight through or tunnel type
• The washer has rinsing, detergent spraying, hot
water rinsing, steaming and air-drying sections
(Fig.).
• The cans are moving from entry door over the
steel or plastic chains of special design to hold
the can and carry towards the exit door.

31. Assessment of Effectiveness of
Cleaning and Sanitization
Visual inspection:
• In large tanks/silo proper light arrangement is made to inspect
cleanliness status.
• Remote places could be inspected by focusing powerful light over the
surface.
Touching
• Touching the cleaned surface with clean & sanitized fingers shall help
in knowing the presence of physical/chemical matters.
• Detergent residue gives whitish appearance over the fingers, whereas
presence of milk fat gives oily impression.
Drop test
• When clean water is dropped over the inclined/vertical surface, it gives
specific flow pattern depending upon the extent of cleanliness.
• Excessive water-liner breaks could be observed on improperly cleaned
surface.

32. pH test: more than 7 indicates alkalinity
Indicator test: phenolphthalein indicator
test
Rinse method: The sterilized surfaces are
rinsed with distilled water. The result is
presented to know the microbial load as colony
per litre of rinse.

33. • Swab method: The sanitized surface is wiped with a
clean and sanitized cotton and rinsed with the distilled
water of known volume.
•
• Adinosine-triphosphate (ATP) tests provide an
indication of viable micro-organism within few seconds
and assess the effectiveness of sanitization. This test is
useful in correcting the cleaning/sanitizing process well
before the commencement of production.

34. • These tests can be made on the surfaces of the
equipment after completion of the CIP
programme.
• It applies to tanks and pipe systems, especially
when excessively high bacteria counts have
been detected in the products.
• Samples are often taken from the final rinse
water or from the first product that passes
through the line after cleaning.

35. Conclusion
• Cleaning is the important factor in dairy
processing industry.
• Efficiency of cleaning improves the dairy
product quality.
• Without proper cleaning, the milk will spoil
easily.

36. Reference
• https://dairytechnology.blogspot.com/2014/12/
dairy-technology.html
• https://www.slideshare.net/Geeta12344/dairy-
and-meat-processing-plants-cleaning-by-geeta-
chauhan
• https://www.cleanindiajournal.com/cleaning_i
n_dairy_industry/
• Text Book of Dairy Chemistry by for ICAR
M.P.Mathur, D.D.Roy & P.Dinakar
• Outlines of Dairy Technology by Sukumar De.