aavin

Indian Institute of Crop Processing Technology

Ministry of Food Processing Industries, Govt. of India

Training on detailed study on Salem diary processing unit

Under Graduate B Tech – Food Processing Engineering

Report

for

IN PLANT TRAINING

Present by

K. Prakash

Worked from

14.06.2012 to 27.06.2012

Submitted on

27.06.2012

1

ACKNOWLEDGEMENT

First of all I thank “THE ALMIGHTY” for giving me a chance to complete my

training programe at Salem Aavin.

I express my gratitude to our respected General Manager MR. KATHIRAVAN, for

his guidance and caring during the training programe. I also thankful to DGM (Dairying)

M.PERIYASAMY and AGM (dairying) M.SEENAN for their valuable advices and co–

operation given to me.

I also extend my gratitude to towards all JDO’s and JE’s of Salem dairy. Especially

to Thiru. D.TANGARAJAN spl.gr.D.m (D).

THANK YOU

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Content:

Introduction.

Milk definition.

Over all processing of milk and its products.

Types of milk.

Raw milk reception.

Milk processing.

Milk pasteurization.

Homogenization.

Refrigeration.

Butter.

Ghee.

Powder plant.

Aseptic packaging section.

Lab unit.

Sweet section.

Prepacking section.

Effluent treatment.

Boiler.

Microbiology of milk.

Milk analysis,

(i) Bio chemical test.

(ii) Microbiological test.

Conclusion.

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INTRODUCTION

The Salem district co-operative milk producers union Ltd., (SDCMPUL) was

registered on 10.07.1978 under Tamilnadu Co-operative societies Act and started functioning

from 07.10.1978. The commercial productions products are butter, ghee and skim milk

powder started on 16.08.1983 with the help of NDDB. Its main aim is to procure the milk

with good payment and to cater the needs of the metro dairy’s local demand and to convert

the surplus milk into butter, ghee and SMP.

The dairy complex is situated in about 46 acres of land bounded by sithanur and

dhalavaipatty villages.

In the earlier stages the union has procured only a quantity of 33,000 litres of milk per

day with its 227 primary milk producers Co-operative societies. Then the union gradually

developed its activities and reached a daily average of 4, 51,371 litres per day (LPD). At

initial state, the dairy was started functioning with a handling capacity of 10,000 LPD, which

was subsequently increased, to approximately 4, 00,000 LPD. Under SDCMPUL 3 chilling

centers located at Attur, Namakkal, and paramathivelur.

The SDCMPUL is a pure Co-operative sector. It is worked grade name Aavin. Entire

dairy follows 3-tire system.

1. Primary milk producers Co-operative societies.

2. District union level.

3. Milk producer’s federation ltd.

OBJECTIVE

1. Assure a remunerative price for the milk produced by the member of the milk

producer’s Co-operative societies through a stable, steady and well organized

market support.

2. Distribution of quality milk and milk products to the consumers at reasonable

price.

3. Reducing private sector’s monopoly activities.

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VISION

Reducing the artificial demands of the milk and milk products.

Provide milk and milk products at lower cost.

Following quality policy.

Stand by the international markets.

MISSION

Established the producing sectors.

Developing the employee’s skill.

Increasing the profit of the company.

Using advanced technologies for manufacturing.

Tie up with international sectors.

Create employment opportunities to rural areas.

QUALITY POLICY

Significant investment has to be made in milk procurement, equipments, chilling and

refrigeration facilities. Also, training has to be imparted to improve the quality to bring it up

to international standards.

Salem Aavin is committed “to supply milk and milk products and satisfaction of

customers by adopting best standards in a hygienic and safe environment with continual

improvement of quality with motivation, commitment and training of employees”.

Salem Aavin milk production Ltd was awarded from ISO 9001:2008.

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AWARDS AND REWARDS

ISO 9002 awarded for production, supply of milk, skimmed milk powder, butter, ghee

and UHT milk in tetra pack.

Aavin Salem is an ISO 9001:2000 certified organization since 24.10.2002.

Tamilnadu state government supported to the company. They reduce the taxes for the

milk and milk made products.

Government gives loans at very lower interest and sometimes government discounting

the loan also.

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ORGANIZATION CHART

7

MANAGING DIRECTOR

(MD)

ASSISTANT MANAGING DIRECTOR

(AM)

GENERAL MANAGER (GM)

DEPARTMENTAL GENERAL MANAGER (DGM)

MANAGER (DGM)

EMPLOYEES

1. REGULAR EMPLOYEES IN UNION – 672. 2. DAILY WAGE EMPLOYEES IN UNION

(APPROX) - 300

MILK PRODUCTS

The Aseptic packaging section and skim milk powder plant are the unique features of the

dairy. The products being prepared are:

1. Processed milk (Aavin gold, Standardized milk and Toned milk).

2. Butter.

3. Ghee.

4. SMP (Skim Milk Powder).

5. UHT Milk (Aavin homogenized and standardized, flavored milk, Amul Shakthi &

Amul Gold) and coconut thunder.

6. Tetra packed fruit juice.

7. Peda, Mysore pa, Sona Papdi, Halwa.

8

SALEM DIARY PROFILE

Arrival of the Tamilnadu Dairy;

Development co-operation team October 2nd ,1974

Starting the first set societies November 10th ,1974

Registration of SDCMPU July 10th ,1978

Starting of SDCMPU October 7th ,1978

No. of societies affiliated 1101

No. of societies functioning 1049

Milk payment schedule Once in 10 days

Milk payment schedule LPD

Processing capacity 3 day

Powder plant capacity 10 T/day

Butter 4,144 kg/day

Ghee 961.3kg/day

Refrigeration 280 T/day

Boiler 5 T/hr

Milk marketing 60.30 Lakhs LPD

BMC 73978 LPD

Chilling centre capacity

Attur : 12,31,20LPD

Namkkal : 4,42,00LPD

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Velur : 4,08,03LPD

Total no. of farmer members 3,26,684

Women members 1,10,693

Pouring members 47,587

No. of rural milk collection routes 568

Daily average procurement in litres 3,97,727

Maximum milk procurement 4,47,675

Local milk sales 1.38 Lakhs litres/ day

Processing capacity 3,00,000 litres/ day

MILK

DEFINITION

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Milk is the physiological secretion of normally functioning mammary glands. Milk

may be defined as the whole, fresh, clean, lacteal secretions obtained by the complete milking

of one or more healthy milk animals.

Milk is an emulsion of butter, Fat and water. In milk, the continuous phase is water

and aqueous phase is protein, lactose, minerals and traces of other substances such as

enzymes, vitamins, gases, etc.

PROCESSING OF MILK

Can milk (20-25˚C)

Chiller way (3˚C)

Raw milk (5 - 1, 00,000 L)

Pasteurization (72-75˚C for 5 sec)

Homogenization (Fat separation)

Separator process (78-80˚C)

Cream skim milk

Butter & ghee milk powder

Constituents

Major : water, Fate, protein, lactose, ash or mineral water.

Minor : phosphor lipids, sterols, vitamins, enzymes, pigments etc.

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True : milk Fat, casein, lactose.

Chemical composition of milk

Water : 87.0%

Fat : 4.0%

SNF : 8.0%

Casein : 2.8%

Albumin + globulin : 0.6%

Lactose : 4.7%

Milk ash : 0.7%

Citric acid etc : 0.2

Types of milk:

F (%) SNF (%)

Skimmed milk : 0.08 8.5

Standardized milk : 4.5 8.5

Toned milk : 3.5 8.5

Aavin gold milk : 5.0 9.0

OVER ALL PROCESSING OF MILK AND ITS PRODUCTS

Receiving of milk

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Filtration and Clarification

Dehydration Chilling Boiling

Khoa Standardization Cooling

Standardization milk Added milk

Double toned milk Curd

Sterilized milk

Pasteurization

Skim milk Cream separation Flavored milk Addition of water

Spray drier Butter churner Storage tank Addition of flavor to the milk Butter milk

Skim milk powder Butter Packaging Bottling

Packaging Butter melting Sterilization

Storage Ghee boiler Cooling

Ghee packing

RAW MILK RECEPTION DOCK (RMRD)

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CAN RECEPTION

Milk is received at the processing dairy in cans direct from societies and in tankers

from chilling centers. The milk is received in the plant twice daily-morning and evening. The

morning collection start at 8.00 am and ends at 11.30 am, on an average of 95,000ltr. The

evening collection starts at 7.00 pm and ends 10.00 pm, on an average of 73,270ltr. The dairy

covers 24 routes and 3 chilling centers.

AVERAGE MILK PROCUREMENT PER DAY

Total procurement : 4,51,371 L

Can reception : 1,73,730 L

Tanker reception : 2,28,305 L

Attur : 1,23,120 L

Namakkal : 44,200 L

Paramathivelur : 40,803 L

BMC : 73,978 L

RECEPTION

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Can Reception

Milk cans (received from societies)

Cans are unloaded directly from the trucks upto load by power driven conveyor

Automatic lid open machine

Organoleptic test (doubtful milk cans segregated for COB test)

Storage

Separate Fat

Spoilage milk

Dumped into weighing bowl tank and weighing through electronic weighing balance and

sample is collected (weighing machine capacity 1.1500L, 2.1000L)

From the collected sample Fat and SNF is recorded by using milko-tester and lactometer

(accordingly payment will be made to societies)

Milk is left to dump tank and empty cans are cleaned by passing through can washer

The raw milk is pumped to the processing section

Cans type : SS and Aluminum

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Can capacity : 40L

TANKER RECEPTION

Weighing empty tanker

Tanker loading-collection

Weighing in loading tanker and milk (5˚C)

Plunger help in the agitation

Organa leptic test (temporizing Fat & SNF)

Transport silo tank (5˚C)

Tanker weight formula

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Total weight - (kg) empty wt + milk weight

Cross weight - kg (empty weight)

Net weight - kg (milk weight)

Total weight - cross weight

Net weight

(Kg) convert to litre - weight

Specific gravity

LAB

◌ Modified rich mond’s formula;

SNF = CLR (84˚F) + 0.2 × FAT + 0.36

4

◌ Methylene Blue Reduction Test (MBRT)

10 ml milk with 1 ml of MBR at 37˚C.

◌ Ethylene Dyammine Tetra Acidic Acid (EDTA)

In this method, protein and lactose dissolving. 0.5 ml In and Out + 6.5 ml EDTA. Based on

Homogenization operation.

◌ Clot On Bottling (COB test)

Just heating in furnace and analyze the changes in milk.

◌ Organaleptic Test

◌ GERBER Test

10 ml acid and 90 % H2SO4 Conc. + 10.75 ml milk + 1 ml oH. Rotate at 1400 RPM speed.

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◌ Infra Red Moisture Meter

In this, SMP is analyzed and the readings can be compared and calculated using the scale.

◌ Centrifuge

Based on homogenization operation.

CAN WASHER

Drip saver

Soft water rinse

Washing soda (1%60˚C)

Hot water rinse (90˚C)

Hot air sterilization (120˚C)

Can tilting device

Capacity (11 cans/ min)

The route vehicles arrive at the dairy at the prescribed time. Milk is received in cans

at two points in reception dock, each consisting power driven conveyor, ripping bar, weight

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bowl, dump tank, electronic milk recorder, straight through can washer and one can scrubber.

Reception operation is carried out by 15 workers including milk recorders.

The cans from vehicles are unloaded society wise into can conveyor. Before the cans

are unloaded into the weight bowl, organoleptic tests are conducted for each can and doubtful

cans are separated and are tested for COB. The sour milk is collected separately and it is

accumulated for sufficient time in barrels and then it is taken for sour ghee preparation.

The good quality milk is dumped into the weight bowl. Here, the composite sample

for the society separately for cow and buffalo milk is collected (80ml as sample). The sample

thus collected are tested in a separate reception lab for Fat and SNF to make payment to the

society accordingly. The milko tester, lactometer and butyrometer (Gerber method) are used

to do the above tests.

In the bowl the weight of the milk is recorded through the electronic balance. The

electronically controlled weighing balance can be directly connected to the computer to

record the weight of milk. After collecting the sample and recording the weight the milk is

left to the dump tank. The cans that are unloaded are fed to the straight through can washer.

The drip saver is in use to collect the draining milk from cans.

There are two electronically controlled weighing balances, two incoming and

outgoing conveyors and two straight through can washers. Two milk recording persons are

employed to receive the milk. The movement of cans through conveyors is controlled by milk

recorders with the help of electronic control panel. In the can washer the cans are cleaned and

sterilized and are loaded back to the route vehicle through another conveyor. Washing soda

(0.8-1%) solution is used as the detergent in the can washer and steam is to used as the

sterilizing media.

In the case of tanker milk received from the chilling centers, after the arrival of

tankers, the tanker is taken to the electronic weigh bridge to record the gross weight. After

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recording the weight, the seals are checked and are opened to draw samples. After thorough

mixing of milk in the compartments, the temperature of milk is noted and sample are taken

for analysis of Fat, SNF, acidity, COB and MBRT. If the milk passes all the quality tests, the

milk will be taken to the storage tanks through the plate chillers. After unloading the milk

from the tankers the empty tanker is again weighing to record the actual weight of the milk.

CIP

Cleaning in place.

There are 4 sections in CIP;

1. Raw water (5 mts)

2. Hot water at 80 – 90˚C (10 mts)

3. Lye at 80˚C (10 mts)

4. Cl2 (5 mts, 100-150 ppm soft water)

Cleaning will takes place maximum 7 hrs then Caustic soda solution will be circulated for 30

mts.

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SILO CIP CLEANING

Raw water (5 min)

Hot water (90˚C, 10 min)

Caustic soda (1%, 90˚C, 10 min)

Raw water (10 min)

Chlorine water (100 ppm, 5 min)

Total time for CIP cleaning is about 45 min.

MILK PROCESSING

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FLOW CHART FOR MILK PROCESSING

Receiving milk (grading, sampling, weighing, testing)

Cooled to below 10˚C & stored at raw milk storage tank 35-40˚C)

Pasteurization (82˚C, 2 min)

Filtration/clarification (duplex filter)

Cream separator (40-45˚C)

Cream Skim milk preheating in regeneration II

Heating (90˚C) heating (75-78˚C) Homogenization (70˚C)

Holding (15 sec) holding (15 sec) Homogenization I stage

Chilling (10˚C) Chilling (5˚C) Homogenization II stage

Storage at (10˚C) Stored in silos heating (75-78˚C)

Butter churner Powder plant holding (15 sec)

Butter Skim milk powder Chilling (5˚C)

Melting (105-110˚C) Packing

Stored in silos

Ghee Storage 25 kg/pack

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The cream which is separated taken to the storage tanks (Chilled water circulated

vertical SS tanks). After pasteurization in the cream pasteurizer this cream is used for butter

making and also for standardization. A part of the skim milk is transported to Chennai.

CIP cleaning is done after each processing. Manual cleaning is also done periodically.

The floor cleaning is done using teepol and washing soda.

The milk from the dump tank is pumped to the plate chiller. Here the chilled water

temperature is around 1˚C and is used as cooling medium and it chills raw milk to below 5˚C.

The chilled milk is stored in raw milk storage tanks. The milk kept in raw milk storage tanks

is tested for temperature, acidity, Fat, SNF, MBRT.

Floor of reception dock is made of concrete trowel with cast iron. Floor and

equipments are cleaned thoroughly using teepol after each reception operation.

The milk which is chilled and kept in the raw milk storage tanks is taken for

pasteurization later. In the pasteurizer, milk is heated upto 75-78˚C for 15 sec with hot water

and again chilled to 5˚C. The pasteurized milk is stored in the silos (SS storage tanks). A part

of the milk is used for cram separation. The milk from regeneration section of the pasteurizer

enters the centrifugal cream separator which separates Fat from milk. The cream goes to the

cream pasteurizer. The skim milk goes back to the milk pasteurizer where it is pasteurized

and stored in the silos. The skim milk is used for standardization and for the preparation of

SMP.

For milk bulk vending supply and also for local supply (Toned milk, STD milk, high

Fat milk) milk in the draw milk tanks is standardized by using cream and SMP and then it is

taken for pasteurization and homogenization and kept in the silos.

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The milk which is processed and stored in the silos is tested for temperature, Fat,

SNF, acidity and MBRT, if it is found sub standard the milk is standardized to the required

quality. Then it is issued to the sachet filling and to the tankers through the plate chillers.

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MILK PASTEURIZATION

Milk pasteurization consists of 4 sections. They are given below;

1. Regeneration section.

2. Heating section.

3. Holding section.

4. Cooling section.

1. Regeneration section:

The chilled milk first enters the regeneration section and the temperature of the milk

raised to 40 ˚C. In this section the raw milk is being heated by the outgoing pasteurized milk.

2. Heating section:

Immediately after regeneration section the milk is sent to heating section where the

temperature is 72.4˚C. Then the milk is passed to holding section.

3. Holding section:

Milk enters into the holding section where the holding time is exactly 15 sec, which is

found to be optimum. In modern practice, the milk is passed through a pipe and the flow

is arranged in such a way to achieve the correct temperature at 72˚C. Milk is then sent to

the regeneration section where the temperature is reduced to 40˚C. Hence, milk is cooled

prior to cooling section.

4. Cooling section:

The milk is sent to cooling section where the temperature is gradually reduced from

24˚C and then finally the temperature is reduced to 5˚C.

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HOMOGENIZATION

The process of making a stable emulsion of Fat and milk serum by mechanical

treatment termed as homogenization. The diameter of Fat globule size in raw milk ranges

from one to fifteen microns. The specific gravity of the Fat is 0.87. It is considerably low than

fluid skim milk (1.032)

By homogenization, the Fat globules are broken upto smaller ones, the size less than

two microns in diameter. Satisfactory homogenization can be achieved by maintaining the

temperature approximately at 70˚C.

Construction

The high-pressure homogenizer consists of single acting triplex with each cylinder

having a section and discharge valve. The discharge valve of each pump empties into a

common discharge pipe which is provided with special valve.

These machines function by forcing the milk Fat under pressure through a very small

orifice with the result that the Fat globules are broken apart and remain dispersed in stable

emulsion in the milk serum.

High pressure homogenization may be operated at pressure ranging from 500 to 5000

pounds per square inch (PSI).

COOLING

After homogenization milk is cooled below 5˚C, with the help of plate heat

exchanger.

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REFRIGERATION

Alternative processing of condensation and evaporation called refrigeration.

Ammonia refrigeration is used for cooling the water. The low temperature and low

pressure ammonia vapor from the evaporator is passed to compressor. Inside the compressor,

the ammonia vapor is compressed to high pressure and temperature. In order to have a free

movement of piston, serve lubrication oil is used. Ammonia vapor reaches a high temperature

of 100˚C to 140˚C and high pressure of 180 pounds.

The ammonia vapor is then passed to condenser. In the condenser, the water is used to

cool the ammonia. During the cooling, ammonia vapor is cooled and changed to ammonia

liquid, which comes out from condenser.

Low temperature liquid ammonia is stored in receiver which is then pumped to

evaporator. In between tube, pressure is dropped with the help of flow diversion valve. So,

180 PSI is reduced to 30 PSI. During this time ammonia is cooled immediately to below 0˚C

and cooled ammonia is passed to evaporator. Hence, heat exchange takes place and water is

cooled to below 5˚C. In this dairy, there are three varieties of refrigeration unit namely 9×9,

7×7 and 5×5. Chilling the water upto 1˚C and for cooling the room upto -21˚C this unit is

used.

The low temperature and low pressure ammonia vapor is passed to compressor and

process is continued.

Compressor

- Reciprocating type (9×9)

- 18˚C & 30 PSI pressure

- Discharge gas at 180PSI at 100˚C

- Oil separator (removal of oil from compressor)

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- Boost compressor is used only for cooling room at -˚C

Condenser

- Evaporative type

- Water spraying and air blow system

- Converting ammonia gas into liquid at pressure 180-175 PSI at normal temperature.

Expansion valve

- Main work is to reduce the high pressure suddenly

- Temp to -˚C

- Converting ammonia liquid to vapor

Over view

Compressor capacity (6) : 70 ton

Condenser (7) : 75 ton

IBT (Ice Bank Tanks) : 50, 000 ltr (each)

Other 4 tanks : 45, 000 ltr

Ammonia liquid compressor condenser

30 PSI at normal room (180 PSI at 100˚C)

Temperature liquid receiver

Expansion valve

Evaporator

Refrigeration cycle in Aavin

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BUTTER SECTION

Butter serves as the balance wheel of Salem dairy. The surplus milk is converted into

butter and a portion of it to ghee. Pasteurized cream at 8-12% from cream storage tanks are

taken for butter preparation, with the help of butter churn or continuous butter making

machine. The butter obtained is either used for conversion into ghee or for sales in 500gm

packs or 20 kg bulk packs.

OPERATION OF BUTTER SECTION

The capacity of the chuen is around 5000 L. After proper cleaning with chlorine

water, the cream is pumped to 1/3 of the churn and closed. The chilled water, spray and the

motor is started. The churning occurs at 28 rpm, peaking at 8 rpm, and final stage at 15 rpm.

The whole operation of a batch takes around 1-2 hrs for completion. Table butter is prepared

in the butter churn only. Salt is added at the final working by sprinkling. If any color is added

(not done now) it is added to cream.

OPERATION OF CONTINUOUS BUTTER MAKING MACHINE (CBM)

The CBM comprises of 3 units that are arranged on top of each other. These are the

beater, the draining unit and the kneader. The cream is fed to the CBM through a screw pump

(for continuous air free flow). The cream enters the beater, where cream gets separated into

fine butter granules and butter milk.

The butter rotates at 900-2200 rpm. Butter milk is drained off and the granules are

washed and worked in the separator with chilled water supply. The butter then passes through

a kneader (a twin screw conveyor) for the air-free flow of the butter. The Fat % of the butter

obtained from CBM is around 82-84% milk Fat. The quantity of butter depends on the inlet

temperatures and Fat content of the cream. For sweet cream, the optimum range of cram Fat

content is between 45 and 50 %. For sour it is between 38 and 42 %. The butter milk drained

from the butter churn and CBM is checked for Fat, SNF and acidity. If the acidity is normal,

it is mixed with the raw milk.

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BUTTER PACKING MACHINE

The packing machine is of complicated mechanism working on a motor and a vacuum

pump. The butter to be packed is fed manually into the hopper, which has twin screw

conveyors into a mould on a rotating head, which helps in the continuous supply of butter.

The vacuum pump helps in parchment paper movement 500 g blocks are wrapping in

parchment paper. This is packed manually in cartons.

Major portion of butter manufactured by CBM is used for build packing ie. 20 kg

cooking butter in CFB cartons. This is used for melting purpose and also dispatched to other

dairies like mother dairy, Calcutta.

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BUTTER

Butter may be defined as Fat concentrate obtained by churning cream gathering the

Fat as a compact mass and then working it without the addition of common salt. It should be

free from other animal Fat and mineral oils.

Cream

Storage tanks (3 hrs at 10˚C)

Usage of butter churner

Butter milk Butter

Storage in tanks Storage at 16˚C for ripening

Packaging Packaging and storage in -21˚C

Store in room temperature Grading

Marketing Marketing

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ICE CREAM PREPARATION

- Ice cream powder (4 kg)

- Heat the raw pasteurized milk at 80˚C (18 ltr)

- Add 6.5 kg of sugar

- For thickness add stabilizing powder (200 g)

- Cream (10 ltr)

- 4 hrs heating at 100-140˚C

- Chilling at 4˚C

SEVERE BUTTER

EDPL (not good for health)

Official use.

SOUR GHEE

Official use.

15 kg/ 16 kg yielding process.

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CLEANING

The cleaning done in butter churn is CIP, which is done after each batch. The cleaning

process is,

Cream removal

Hot water

Teepol

Raw water

Hot water

Steam sterilization

Chlorine water

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GHEE SECTION (PRE-STRATIFICATION) METHOD

The butter is dumped into melting vat of 1000 L capacity (81-83% Fat)

Melting is done by circulating Hot water through the will inside the vat

Here butter is melted to a temp of 80-90˚C & gets converted into butter oil

The method butter forms 3 layers with operative and particle at the top, Fat at the middle &

butter milk at the bottom

Drain the serum & pumped melted & Fat into the ghee kettle. This process is known as

‘Pre-stratification method’

Heating upto 105-110˚C by steam the sides of the kittle & allowed to stand for 1 hr so, that it

attains golden brown color.

From the Ghee kettle pump the ghee to the setting tank through the clarifier

Cooled at 40˚C

Fill in the container through filter according to the requirements 15 kg tin, 1 kg, ½ kg,

1000ml, 500 ml and 200ml.

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POWDER PLANT

Salem dairy gas got a well equipped powder plant for the production of SMP. The

designed capacity of the plant is 10 T/day. But, the actual production capacity is 8 T/day.

This is due to less TS (8.4-8.6%). According to designed capacity if the SM has 9.4% TS,

then the output will be 10 T/day. Powder plant consists of 2 sections, an evaporating unit for

concentrating SM to TS level around 40-45% and a spray drying unit for converting the

concentrated milk into powder. Out of 4.5 Lakhs liters of milk procured, about 60,000 L of

pasteurized skim milk is used for the manufacture of SMP. Powder plant has got 2 skim milk

silos each having storage capacity of 60,000 L.

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FLOW CHART FOR EVAPORATOR PLANT

Skim milk (6˚C)

Barometric condenser (40-45˚C)

Regeneration at calendria III (48˚C)

Regeneration at calendria II (56˚C)

Regeneration at calendria I (68˚C)

Pasteurization (90˚C)

Holding section (15 sec)

Calendria I (68˚C, 17.52% cone)

Calendria II (56˚C, 44% cone)

Calendria III (48˚C, 32.94% cone)

Condensed milk (40-45 % TS)

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The evaporating unit is equipped with a falling triple effect evaporator to minimize

steam consumption. The SM from the silo is fed to the evaporation plant at a rate of 4800

kg/hr (due to less total solid content in skim milk), but the designed capacity is 5100 kg/hr.

After receiving the lab report, SM is pumped into the feed balance tank. From the FBT, the

SM is pumped to the condenser through coiled tubes where the SM at 6˚C is preheated to

around 40-45˚C by the vapor collected from the evaporator. Then, the SM at 45˚C is passed

through the calendria III, II, I respectively where in all these calendria, the incoming SM is

heated by the outgoing heated milk. Then the milk enters the pasteurizer and held at

pasteurization temperature (90˚C) for 15 sec.

After pasteurization, milk enters calendria I where vacuum is maintained at the level

of 580 mm of Hg, hence boiling of milk occurs at 68˚C. The vapor and the milk enter vapor

separator, from their milk is pumped to calendria III, boiling occurs at 48˚C and a vacuum

level around 680 mm of Hg is maintained. Then that milk is pumped into calendria II where

final boiling occurs at 56˚C and vacuum level is 620 mm of Hg. Then, the concentrated milk

is pumped to the feed balance tank of the spray dryer. On the way to feed tank the

concentration of milk is analyzed by using Baume refractometer. The condensed milk should

have a Baume reading of 19-22, which is correct concentration for spray drying process.

In the case of lower Baume reading, the milk is again sent to the evaporator through

the balance tank. The vapor condensate from condenser is mixed with water and it is pumped

to spray pond for cooling. The cooled water is again re circulated to the condenser.

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EVAPORATOR DETAILS

No. of tubes in calendria I, II & III - 187,110,110 respectively

Steam pressure - 14kg/cm

Calendria I

Jacket temperature - 78˚C

Vapor separator temperature - 68˚C

Calendria II


Calendria III


Condenser water inlet temperature - 30˚C

Condenser water outlet temperature - 38˚C

Pasteurization temperature - 90˚C/cm2

Steam pressure for t9hermo compressor - 14kg/cm

Milk feed rate - 5100 kg/hr

Initial total solid content - 8.5%

Final total solid concentrate - 40-43%

Water evaporation - 4040 kg/hr

Concentrate output - 1000 kg/hr

Steam consumption in tubular & pasteurizer - 1200kg/hr

Condensate temperature

Calendria I - 78˚C

Calendria II and III - 55˚C

38

PERFORMANCE DATA

Ambient temperature : 30˚C

Concentrated feed at 45˚C : 1060 kg/ hr

Water evaporation : 560 kg/ hr

Solid concentration in the feed : 40-45 %

Feed temperature : 53-55˚C

Inlet hot air temperature : 185-190˚C

Outlet hot air temperature : 88-90˚C

Powder moisture : 3.4 %

Supply air quality : 17,000 kg/ hr

Conveying air quality : 4000 kg/ hr

Pressure drop under main cyclone : 130-150 mm WC

Pressure drop under product cyclone : 150-175 mm WC

Chamber vaccum : 10 mm WC

Steam consumption at 14 kg/ cm2 : 1260 kg/ hr

Energy consumption : 112 KWH

Powder production : 500 kg/ hr

Powder temperature at packing : 40˚C

Powder storage silos : 4*1000 kg

39

POWDER FILLING SECTION

The powder from the spray drier is filled into 25 kg bags. Then they are stitched in a

stichwell machine. Stitching is done by pressing the pedal manually at the bottom of the

machine. Capacity of the filling section is 15 bags/ hr. After filling the powder in the 25 bags

they are stored in godown having capacity of 400T at the room temperature. Insecticides used

in godown are malathene, Hit Beccan Spray for controlling Rats and insects.

Arranging, 5

8

8 × 5 = 40 × 15 = 600 Bags.

CLEANING PROCEDURE

The CIP cleaning employed in the powder plant is as follows:

Raw water : 15 mts

Lye (1.5 % Na2CO3 : 30 mts

Hot water : 10 mts

Acid (HNO3, 1%) : 15 mts

Lye : 5 mts

Hot water : 15 mts

Total : 90 mts

For evaporator plant, either after 18-20 hrs of plant operation or 45000-90000 L of

skim milk is taken for evaporation, the plant is cleaned by CIP.

40

For spray drying plant, clean the entire feed system at the end of each run with caustic

solution (1.5%). Concentrate tank is also cleaned manually. The powder deposits on the walls

can be collected by hammering. This procedure is followed after every run (20 hrs). Manual

cleaning of the drying chamber is carried out weekly once. The chamber door is opened and

suction fan is put on. Then the entire sticking particles are swept off using a brush.

ASEPTIC PACKAGING SECTION

The unique feature of an Aavin Salem-“The aseptic packaging station” started

functioning on 1987. Among Tamilnadu milk production federation Ltd only Aavin Salem

owns this facility.

This unit is well equipped with one TBA-9 (Tetra Brick Aseptic) for 200 ml and one

TBA-3 machines for 1000 ml packing, one Tetra Fino Aseptic (TFA) for 500 ml packing, one

shrink wrapper machine, and one straw application, UHT pasteurizer and a pasteurizer for

fruit juice. An ink jet machine for printing labels on packets in also available.

Good quality raw milk (negative in 70% alcohol test) is selected pasteurized and

sends to the UHT plant. The milk is then homogenized and heated at 140˚C for 2 sec and

send for aseptic packaging; indirect heated concentric tube coils are used to manufacture

UHT milk. Back pressure about 0.5 bar and milk pressure about 5 bar is maintained. Two

stage homogenizer is used (1st stage 200 bar, 2nd stage 50 bar).

41

Before production, plant is sterilized by circulation of hot water at 142˚C with back

pressure. The inlet temperature of milk is 5˚C. First regeneration outlet is 65˚C, 2nd

regeneration outlet is 115˚C, heating section is 140˚C and outlet temperature of milk is 30˚C.

Milk after UHT process should be negative in 85 % alcohol test.

The concentric coil is made of high grade chrome nickel steel. Two pipe concentric

coils are used for heating the milk with steam and three pipe concentric coils is used for

regeneration section.

Three aseptic packaging machines are used for packing the milk. The machines are

sterilized by hot air and spraying H2O2 in the system. Any milk contact part dismantled for

cleaning is kept in H2S2 (5% solution) until it is reassembled into the machine.

Seven layer packing material is used for aseptic packaging. The seven layer package

is made of three materials namely PE, paper and aluminum foil.

First, water is used to check the sealing strength and machine conditions. The milk is

pumped. The packing material is sterilized by smearing by smearing of H2O2 and PSM (poly

sorbito monolaurate) mixture by machines when it is drawn from the rolls. The tetra packs

are taken by the conveyor for packaging in tetra pack trays which is again sealed with PE

film by using shrink wrapper machine. This trays are then stored at room temperature. The

packed samples are kept for 7 days (37˚C) and tested for any abnormality. Strict quality

measures are followed right from the selection of raw milk till the product is released in the

market.

42

FLOW CHART FOR UHT PROCESSING

Chilled milk (5˚C)

Pre heating by regeneration I (65˚C)

Homogenization Ist stage (200 kg/cm)

Regeneration II (115˚C)

Main heater (140˚C, 2 sec)

Regeneration II (115˚C)

Homogenization II (50 kg/cm2)

Regeneration I (65˚C)

Product cooler (25˚C)

Aseptic packaging

43

CARDAMOM/ PISTA/ STRAWBERRY FLAVOURED MILKS

Ingredients

Sugar - 8.5%

Flavor - 55 ml/ 1000 L

Vitamin A - 2.2 ml/ 1000 L

Vanilla flavor - 3 ml/ 1000 L

PREPARATION

Sugar is dissolved and made into syrup

Filtered and pumped into silo

Flavor addition

Test for Fat, TS, acidity and pH

Homogenization at 200 bars in first stage

Sterilization at 140˚C/ 2 sec in THE

Homogenization at 50 bars in 2nd stage

Packaging in 200 ml tetra pack at ambient temperature

44

MAAVIN FRUIT JUICE

Mango drink is prepared and marketed under the brand name MAAVIN for which a

separate pasteurization unit is maintained in the APS because of its fibrous nature. The

various ingredients used are;

Mango syrup - 16 %

Sugar - 15.5 %

Mango flavor - 0.01 %

Citric acid - 0.25 %

Ascorbic acid - 0.0025 %

Water - 68.5 %

PREPARATION

Sugar syrup is prepared with hot water at 70˚C

Filtered and pumped into silo

Mango pulp dissolves in water

Filtration

Mango pulp pumped and mixed with syrup in silo

45

Citric acid at rate of 0.25 % is added

Flavor and ascorbic acid addition

Water addition to make up till 4000 L

Test for acidity and Brix conducted

Homogenization at 100 bars at 1st stage

Pasteurization to 98˚C

Packing in 200 ml packets

Custom packing for the other product companies like Amul, sip – on etc., are under

taken here. Amul manufactures toned milk (3.0 Fat, 8.5% SNF) and standardized milk (4.5 %

Fat, 8.5 % SNF) under the brand names Amul Taaza and Amul Gold respectively. Aavin (TM

and STD milks) are available in 1000 ml packs and 200 ml packs (STD).

46

CLEANING PROCEDURE FOR UHT PLANT

Rinsing with soft water (3 mts)

Circulation of lye (caustic soda, 1.5 % at 85˚C, 15 mts)

Raw water circulation (15 mts)

Nitric acid (1.5 % 20 mts, 81˚C)

Raw water circulation (15 mts)

Caustic soda (1.5 %, 20 mts)

Soft water circulation (3 mts)

Total time taken for CIP cleaning is about 2 hr 15 mts.

47

During the 7 days of incubation at 37˚C, three repallestisation are done every two

days for the packages, and are transfer to godown. During repallestisation any damage for

blown packets are checked. Based on the results after both incubation and repallestisation,

trays are cleared. The incubated samples are subjected for sensory evaluation. For this cartons

are cut opened and product is tested for spoilage, flavor and color, Fat separation and

sedimentation. If ant sample is found defective the whole batch is rejected.

CHECKING FOR LEAKAGE IN TETRA PACKS

Mechanical package check

Electrolytic package check

Satisfactory

Unsatisfactory

Leakage type Records

48

1. MECHANICAAAL PACKAGE CHECK

This is performed by pressing manually,

Checking of sealing:

Both longitudinal sealing (LS) and transverse sealing (TS)

TS: By tearing of sealing area and analyze

LS: Check the stip sealing by injecting dye solution

2. ELECTROLYTIC PACKAGE CHECK

This method is based on the electrolytic cell. If there is a leakage in the package or

damage to the inner plastic layer a current will flow through the circuit and ammeter

gives the readings.

3. LEAKAGE TYPE INK TEST

The reagents used in this case are propanol which acts as a solvent and erythrosine

dye. Instead of erythrosine, Rhodamine 6 G solution can also be used. Mix about 2 gm of

dye solution with 1000 ml propanol. After shaking it is left over night and filtrate is used

for the testing (after evaporation). For testing carton is filled with water and it is wiped

inside. Test ink is filled to a level and sure that critical points are being covered. Remove

the dye solution, dry completely by using a dryer then it can be split and check for any

damage in the packet by ink penetration. In order to check proper filling of packages

every half an hour packages are weighed during processing.

49

FLAVORED MILKS

The various flavoured milks prepared are;

Chocolate flavoured milk

Cardamom flavoured milk

Pista flavoured milk

Strawberry flavoured milk

Mango milk shake, Maavin mango juice

These are packed in 200 ml tetra bricks packs.

ABS LAB

A separate quality control lab is functioning in APS. Raw milk is tested for Fat %,

SNF %, TS %, acidity, alcohol, heat resistant, spore count and SPC. Standardization is done

on the basis of Fat and SNF% and alcohol % is found out to assess the heat stability of raw

milk.

PLANT CLEANING

The CIP system is controlled by PLC (Programmable Logic Controller). The whole

process of cleaning is affected by a program card. The plant cleaning is affected through a

plant cleaning unit, which comprises of a double jacket is divided into 2 section-one for

concentrated acid storage and other for concentrated alkali storage. During the cleaning

procedure walls will admit compressed air to ensure correct proportioning of appropriate

detergent and discharge surplus solution to the drain. The cleaning procedure is as follows

(CIP).

50

PRODUCT PROFILE OF AAVIN

In Salem Aavin dairy limited produced milk and milk made products

The product profile was given below.

MILK

Kind of milk Fat % SNF % Liters’ : 500

ML (Approx)

Rate Rs.

Standardized

milk

4.5 % 8.5 % 500 ml 15.50

Pasteurized milk 3.0 % 8.5 % 500 ml 12.50

GHEE

Liters’ Rate Rs.

100 ml 20.00

200 ml 40.00

500 ml 130.00

1 ltr 260.00

5 ltr 1000.00

MILK POWDER

Kilograms Rate Rs.

500 g 150.00

1 kg 300.00

5 kg 1500.00

SWEET ITEMS

Flavor Grams (Approx) Rate (Rs.)

Milk kova 250 gm 65.00

Sone pappadi 250 gm 65.00

51

JUICE ITEMS

Mango juice 100 ml 15.00

Apple juice 100 ml 40.00

Orange juice 100 ml 35.00

CLEANING PROCEDURE FOR UHT PLANT

Rinsing with raw water (5 mts)

Rinsing with hot water (80-90˚C, 10 mts)

Circulation of lye (Caustic soda, (1.5-2%) at 80-90˚C, 20 mts)

Hot water circulation (15 mts)

Nitric acid (2%, 20 mts, 81˚C)


Caustic soda (2%, 20 mts)


Cold water circulation (5 mts)

Total time taken for CIP cleaning is about 2 hr 15 mts.

52

SWEET SECTION

PEDA

In Salem dairy, for milk peda production, 150L capacity double jacketed vat is used.

About 100 litre of milk foe batch is fed to the double jacketed vat. Here heating is done by

steam in which 1.5-2.5 kg steam is applied for the peda production. Continuous stirring cum

scrapping is done till it reaches doubly consistency. At this stage, sugar about 10 % of the

total quantity of the milk taken is added stirring is continued till the characteristics color and

flavor are developed. The milk peda is transferred into crates and is kept for 3 hrs. Generally

it is packed in 250 g boxes and 50 g packs according to the market demand.

MYSORE PA

Aavin, Salem is producing Mysore pa by using pure ghee and sugar as its main

ingredients.

INGREDIENTS

For 10 kg Mysore pa:

Bengal gram flour - 1.2 kg

Ghee - 3.9 kg

Sugar - 5 kg

Cardamom - small quantity

Water - 1000 ml

Initially ghee is boiled in the Mysore pa vat. After boiling the ghee, it is collected in a

separate vessel. Then water and sugar are added into the vat and they are stirred well using

long ladle. After 5 mts of boiling the flour is added into the vat with continuous stirring. Then

ghee is added intermittently with constant stirring. Stirring is continued for 45 min.

53

When the desired consistency reached, the hot mass in the vat is poured into

aluminum trays. The excess ghee in Mysore pa is removed by punching the hot mass on the

tray by using ladle. Then the trays are kept for cooling for 2 hrs. After cooling the Mysore pa

is cut into rectangular shaped blocks by using knife. After weighing, the Mysore pa pieces are

packed in boxes and sent for marketing.

SONE PAPDI

For 12 kg production

Maida - 3 kg

Ghee - 2.7 kg

Sugar - 6.12 kg

Nuts - 0.3 kg

HALWA

For 10 kg production

Corn flour - 1.25 kg

Ghee - 1.25 kg

Sugar - 7.1 kg

Nuts - 0.5 kg

Flavor - Cardamom

Color - Yellow lemon red

54

MARKETING SECTION & STORES

The Aavin, Salem has got a marketing section of its own. The main function of this

section is to supply various products/ milk to the consumers. Out of the 3.15 Lakhs litres of

milk procured around 1.6 Lakhs L of milk is send for local sales through milk marketing

offices (MMO). About 1.2 producing various milk products.

The various dairy products are distributed to various cities through carry forward (CF)

agents. Retailers also market milk products through the dairy own parlors.

Marketing

Milk Products

Type Channels Channels

Varieties

Toned milk Federation Ghee Chennai metro

At Chennai Butter MMO unit

STD milk SMP Dist unions

High Fat milk UHT milk C & F agents

Khoa Whole salers

Mysore pa

Butter milk

55

SALEM

Consumer Salem dairy

Society Marketing

Union at various places

STORES

In the store section, stock is maintained for each and every part of the machines.

Stocks are also maintained for cleaning agents, packing material, fuels, oil etc. the primary

function of this section is to maintain stock for each and every item of the industry and

supplying them during the item of need.

Every section will send the list of needed items to the store section through goods

requisistion note. The store section will send the list of stock items of every section to the

purchase section through purchase request. The purchase section will send quotation

regarding stock items to various firms. The order is sent by the purchase section for the firm

which offers best quality items at subsidiary rates. If the items sent by the firm is not working

properly or any defects are found in the order sent items, the GRN will be returned to the

purchase section and the rejected material is sent to the firm. Scraps will be disposed as

scraped material by calling tenders. The stock verification is done by the auditors annually

(April 1st) and also by the union staff once in 2 months.

56

VARIOUS RECORDS MANINTAINED IS STORE SECTION ARE,

Diary spare parts register I (DSR I)

Dairy spare parts register II (DSR II)

Electronic spares register (ESR)

Stationary book register I (SBR I)

Stationary book register II (SBR II)

Powder plant register (PPR)

APS section register (ASR)

Hard ware’s register (HWR)

Equipment register (ER)

Procurement & input register (P & I)

Consumer dairy register(CDR)

Consumable packing register (CPR)

Service register (SSR)

Old parts register (OPR)

Miscellaneous register

57

DAIRY ACCOUNTS

Some of the major dairy accounts maintained in this dairy are:

Statement of raw milk receipts

Filled and cold storage account statement

Consolidated statement of empties

Milk dispatch particulars

Fat & SNF loss account

Tub account

Statement of poly film usage and wastage

Silo or tank wise milk and cream account

Milk standardization schedule

Processing section – milk & cream statement

Ghee account

Butter account

Statement of consumable and packing materials usage

Spoiled milk and its products account

58

PREPAC SECTION

Prepac section of Aavin, Salem fills the pasteurizer chilled milk into pouches and then

sends it for local marketing through its 24 milk routes. The packing operations are done twice

daily-morning and evening.

Morning: 8.30 am-12.30 pm

Evening: 6.00 pm-2.00 am

In these section 11 double head prepac machines, 3 over head tanks and an outside

silo, crate washer, facility for CIP and cold room are available. For supply of compressed air,

compressors are also located (6 kg/cm) in a compressor room. For easy dispatch, dispatch

section is located at the other side of the packaging sections.

AVERAGE MILK PRODUTION PER DAY

Morning : 33,500 L

Evening : 103,000 L

Total : 1, 36,500 L

AVERAGE PRODUCTION DETAILS PER DAY

STD milk – 74270 L

250 ml – 10555 packets


Toned milk – 8116 L

59


Depending on the marketing interests, type of milk packed and volume can also be

varied. Milk usually packed is;

Standardized milk (4.5,8.5)

Toned milk (3.0,8.5)

STD milk packed in 500 ml and 250 ml pouches. Toned milk only 500 ml packet.

ISI tubes use for carrying the milk sachets are return at one side of the section. After

the manual cleaning of the tubs, these are passed through a straight through crate washer

of capacity 850 tubs/ hr. The cleaned tubs are directly conveyed to the prepac region

where filled packets are arranged in it and send directly for dispatch. The volume of milk

packed depends on the market requirement.

The processed milk from silos is collected in a vertical silo located outside the

section. From the silo, milk is pumped onto an overhead tank from where milk is taken to

the milk is taken to the tank on the top of the packaging machine (40 L capacity). The

filling rolls are fed into the packaging machine simultaneously. After proper sterilization

of the film by UV radiation it passes in such a way that the machine forms, fills and seals

the packages. The sealing temperature and filling quantities are adjusted.

The film used here are co-extruded PE films (50-55µ) which gives a yield of

8600 packets for 500 ml sachets filling per 20 kg roll. On an average, about 25-32 packets

per head per minute are produced. The weight of the milk sachets are tested every half an

hour during packing. The filled sachets are readily sent for dispatch with the help of 25

milk distribution vehicles. CIP cleaning is done after each batch packaging operations.

Manual cleaning is done once in 3 days interval. Acid cleaning is done once in 15 days.

60

PACKING SECTION (MILK)

LDPE Roll – 20 kg in marching (bar side loading)

5˚C Feed inlet in the machine lead tank (40 L)

Operated – setting the volume of milk (250 ml (or) 500 ml)

LDPE – covering the vertical position

Sealing – vertical for temp low Herp (in slid)

Milk volume (Automatic filler)

Scauing – Horizontal and cutting (high temperature)

Manually filled the grade (check the leakage)

Despatch (or) stored

61

EFFLUENT TREATMENT PLANT

For waste water treatment an effluent treatment plant is maintained in the dairy. The

waste will be processing a high BOD which is to be reduced before draining for various

purposes like irrigation.

Waste water

Screen chamber (big particles are sieved and scum being collected)

Equalization tank (BOD is decreased by the supply of air)

Chemical dozer

Clari – floculator with agitator

Aeration tank

Final clarifier

Sludge is drained to sludge bed. The clear solution which overflows is stored and used

for irrigation. The ETP can handle 70000 LPD of waste water. The various standards

mentioned for treated water are;

62

BOD : 30 mg/ L

COD : 100 mg/ L

PH : 8-9

Oil and grease : 8 mg/ L

BOILER (steam generating equipment)

(i) Water tube boiler (used only in power industry)

(ii) Fire tube boiler

Boiler type : IAEC (Indian Agri Engg co.opp)

Model : 1) 1978

2) 1979

Heating capacity : 11200165 / hr or 5 T/ hr

Horizontal packaged fire type : Three phase

Heating surface : 118 m2

Furnace flame : 2.86 m2

Water content fall : 15.7 m3 (Normal)

Steam space : 2.22 m2

Total boiler capacity : 17.92 m3

Water content upto working level : 13.48 m2

Burn flame type & Jeb type : 65˚C

63

Designing pressure : 19.5 kg/ cm2

Working pressure : 16.5 kg/ cm2

Water type : soft water

Furnace oil flame point

Assembling parts in boiler;

- Blow down valve

- Main stop valve

- Feed check valve

- Safety valve

- Air vent valve

- Gauge glass

- Pressure gauge

- Blower

- Feed pump

- Oil pre heater (85-70˚C)

Physio-chemical properties of milk

a. Physical state of milk

b. Acidity

c. pH

d. Density and specific gravity

e. Freezing point of milk

f. Color of milk

g. Flavor

64

Special types of milk

Mixed milk

Homogenized milk

MICROBIOLOGY OF MILK

All the changes that take place in the flavor and appearance of milk are the result of

the activity of microorganisms. Of these microbes the most important in dairy are bacteria

mold yeast and virus – the first once is predominating. Microorganisms are visible only with

the aid of a microscope. Few are a desirable while most cause undesirable changes, a

relatively small portion disease producing types are called pathogen.

Bacteria are microscope, unicellular organism, which occur principally in the form of

spherical, cylindrical, or spiral cells, which reproduce by transverse fission. In milk and milk

products the spherical or cylindrical forms are predominant. They vary from 1-5 mm in size.

Individual bacterial cells are invisible to the naked eye. They form bacterial colonies that are

visible. They are omnipresent. Some bacterial form sporse, which are tough resistant bodies

within the bacterial cells. When they placed in a favorable environment for growth, they form

new vegetative cells. Spore formers cause trouble in the dairy industry of their resistant to

pasteurization and sanitation procedures.

MOULDS

They are multi cellular, they can be observed readily as mycelium. They are found in

soil, feeds, manure and poorly washed vessels, most spores of molds are destroyed by

pasteurization. They are of considerable importance in cheese making and are responsible for

some defects in butter and other milk products.

YEAST

They are unicellular. Their size is larger than bacteria. Most of the spores produced by

yeast are destroyed during pasteurization.

65

SAMPLING OF MILK

The most careful analysis is useless if the sampling if faulty or this sample bottle is

incorrectly labeled. Therefore training in sample is more important.

AIM

To draw representative sample of milk from the bulk.

PRINCIPLE

Milk consists of several constituents of different densities and Fat being lighter tends

to come at the surface. Proper through mixing with proper instrument that is useful for

chemical analysis.

METHODOLOGY

1. Mix the milk thoroughly with the help of plunger.

2. Draw required quality of milk with the dipper and transfer it to the labeled

sampling bottle.

3. Allow the sample to stand for about 4 mins after mixing. Mix the sample by

inverting 3-4 times.

4. Pipette out/ weigh the amount required for analysis it is a fundamental principle of

sampling that the quantities withdrawn must be proportional to the quantities

contained in the respective containers.

MILK ANALYSIS

Biochemical analysis

Organoleptic test

Inference

66

Clot on boiling test

Titrble acidity of milk

Adulterants of milk

1. Urea test

2. Ammonia test

3. Sugar test

4. Glucose test

5. Salt test

6. Neutralizers test

7. Hydrogen peroxide test

8. Formalin test

9. Nitrate test

10. Starch test

SOLID NON FAT TEST

Temperature correction

Modified richmond’s formula

GERBER METHOD

67

MICROBIOLOGICAL ANALYSIS

METHYLENE BLUE REDUCTION TEST

AIM

To determine the amount of bacteria present in milk.

PRINCIPLE

The test depends upon the ability of bacteria in milk. The dye added is a redox dye, in

an oxidized state it remains blue in color and in reduced state it remains colorless. The

bacterium in the milk consumes the dissolved oxygen in milk, thereby reducing the milk.

This brings about the change; the milk gets decolorized to its original white color. The time

taken for changes is noted.

PROCEDURE

1. 1 ml of reagent is added aseptically to 10 ml of milk sample and closes the tube

with rubber cork.

2. Mix and place the tube in the water bath at 37.5˚C.

3. The color of the milk in the tubes is examined after every half an hour and the

time required for complete decolorisation is noted.

GRADING

MBRT time in hrs Quality of milk

5 and above Very good

3-4 Good

1-2 Fair

Below 30 mts Poor

68

PHOSPHATASE TEST

AIM

This test is used to detect inadequate pasteurization.

PRINCIPLE

A phosphate is an enzyme present in milk which will be destroyed at complete

pasteurization. The presence of this enzyme in pasteurized milk is an indication of inadequate

pasteurization.

PROCEDURE

1. Transfer 5 ml of phosphate buffer in a test tube.

2. Add 1 ml of milk sample and close the tube with stopper.

3. Incubate the tubes for exactly 30 mins at 37˚C. Note the color change to yellow

color which indicates inadequate pasteurization.

SWAP TEST

PROCEDURE

The swap is prepared and sterilized. The swap is touched to the side of the silos or any

surfaces and is dipped in 0.8% saline. The swap with saline is mixed well and this saline is

added to macconkey broth medium. After incubation at 37˚C for 24 hrs, the presence of acid

and gas shows the presence of microorganisms which is indication of poor cleaning.

69

STANDARD PLATE COUNT

AIM

To determine the number of colony forming bacteria present in milk.

PRINCIPLE

Milk is added TYDA and incubated at 37˚C for 24 hrs. This is an excellent media for

the growth of lactic acid producing bacteria. When incubated these form colonies which can

be counted. The number of bacteria can be found by multiplying the number of colonies to

the degree of dilution of milk.

PROCEDURE

1. Take 1 ml of milk sample and transfer to the first tube of diluents (9 ml) and shake

well this makes dilution of 1:10.

2. Transfer 1 ml of first dilution into another 9 ml blank to get 1:100 dilution and

serially dilute it till required dilution.

3. Transfer 1 ml from the required dilution to the petriplate and pour the medium and

mix well and incubate it.

STANDARDS

Count greater than 30,000 ml of pasteurization milk. For raw milk upto 10, 00,000 is

good.

70

COLIFORM COUNT

AIM

To determine the coliform bacteria present in milk.

PRINCIPLE

This test is based on the principle that the members of the groups are capable of

producing acid and gas from lactose in the presence of bile salt.

PROCEDURE

1. Prepare serial dilution of the sample and inoculate 1 ml of 1:10 dilution into the

petriplate.

2. Add 10-15 ml of VRB agar, mix well and incubate it for 37˚C for 24 hrs.

KEEPING QUALITY OF MILK

PROCEDURE

1. Collect the sample from the prepack sample once in one hour from production

section. One sample from each route is collected.

2. Samples are kept at ambient temperature with label.

3. Every one hour, after fifth hour of sampling, the COB test is conducted for

samples.

4. The intervals time between initial hour and the hour at which COB become

positive is declared as keeping quality at ambient temperature.

71

Standardization of the milk and milk products

Milk and milk powder Coliform SPC

Raw milk 1:100 1:2 lakes

Pasteurization milk 1:10 1:30,000

Butter 1:10 (yeast & mould) 20 colonies

Powder 1:10 1:15,000

Cream 1:10 1:60,000

72

CONCLUSION

SDCMPU place an inevitable role in tamilnadu milk producers federation Lts,

Chennai. Aavin Salem has got ISO 9001-2000 certification. All the employees and employers

are unitedly working to achieve their goal. Their main aim is to improve the quality of milk

and milk products.

“Aavin” Salem being the first part of my in plant training programme helped me a lot. It was

really a good experience for me. It was guiding to me on the professional side. I hope that this

may help me a lot in my future carrier. I received kind co operation and all the help needed

from the dairy. I thank all for the same, wish them success in all their endeavors.

Thank you

73