MAHANAND DAIRY A BRIEF INTRODUCTION

The Mahanand dairy spread over an area of more than 27 acres, it was established on 18 August
1983, and it is a venture of Maharashtra Rajya Sahakari Dudh Mahasangh Maryadit (MRSDMM).
The main unit is located at Goregaon (East), near western express highway an entry inside the
premises of the dairy welcomes you with lush green lawns, tickling the nostrils with the lovely
fragrance of freshly mowed grass. The layout of entire plant is quite impressive as if it is done in an
organized manner, considering every aspect of comfort easy handling waste management and
energy conservation.

HYGENIC CONDITIONS

Milk is processed, packed and stored under hygienic condition thereby avoiding bacterial
contamination and multiplication. Milk products are manufactured by dairy under hygienic
condition with strict quality control. The dairy plant has ISO9002 and HACCP certification.

ENERGY CONSERVATION

At dairy plant due to continuous joint efforts met to save energy. Significant results are achieved in
the field of energy conservation. There is an improvement of milk handling 27 liters to 42 liters per
KWH. Similarly the furnace oil consumption has reduced from 8.9ml to 2.07ml per liter of milk
resulting into improvement in milk handling from 112litre to 476liter per liters of furnace oil.

WATER CONSUMPTION

Water consumption has been reduced from 4.44 liters to 0.97 liters per liter of milk processed. The
reduction in water consumption has not only helped in reducing cost of milk handling but also
helped in reducing hydrological load of effluent treatment plant thereby reducing the waste water
treatment plant,

1
NON-CONVENTIONAL ENERGY

1) SOLAR WATER HEATING SYSTEM

Since 1990, Mahanand dairy is using Solar Water Heating System. This was commissioned with the
assistance of Department of Non conventional energy source and Maharashtra Energy Development
Agency. The water is heated from 30o to 85oC with the help of solar water heating system, which is
used for boiler as feed water and crate washing & general cleaning purpose. It uses around solar
heating panels. This has resulted into saving of 200 – 250 liters of furnace oil per day, with
monetary savings of approx. rs.8/- Lakhs per annum.

2) ELECTRICITY GENERATION FROM BIOGAS.

At Mahanand dairy, Biogas generated form Effluent treatment Plant is being used to generate
electricity and approx. 500 units of electricity is generated per day, which is being used for running
the electrical motors/equipment at ETP. The biogas generator helps not only in monetary savings
but also in reducing the pollution and maintaining a healthy environment. The system is put under
operation w.e.f. 10/06/99 after completing satisfactory trails.

2
 QUALITY IMPROVEMENT AND CONSUMER SATISFACTION

By adopting proper plant sanitation and quality control measures, the shelf life of Mahanand
milk at ambient temperature could be improved up to 16 – 17 hours. The excellent quality of has
increased the consumer’s acceptability and satisfaction, thereby making Mahanand most popular in
the market. To prevent market complaints and to have effective control over milk adulteration in
market, Mahanand dairy has introduced a very effective coding system on milk pouch. This gives
the details of date of packing, machine number, filler number, place of packing etc. on each and
every pouch packed and distributed in the market.

This has helped us in controlling market complaints and to implement effective corrective
measures at dairy plant to achieve desirable parameters. The system is very useful in solving
marketing and distribution complaints. It also helps improving interpersonal relations with
consumers.

3
 WHAT IS MILK ?

Milk is an emulsion, white in color i.e. the mammary secretion of the mammals.
Milk can be described as oil-in-water emulsion with fat globules dispersed in the continuous serum
phase, a colloid substance of casein micelles, globular proteins and lipoprotein particles, a solution
of lactose, soluble proteins, minerals, vitamins and other components.
The role of milk in nature is to nourish and provide immunological protection for the mammalian
young. The yellowishness of cow milk is due to presence of colostrums, secreted at the time of
parturition.
Milk and its products being highly perishable commodity, due its high water activity, has to be
consumed immediately or must have to be stored at low temperature.

➢ COMPOSITION OF MILK

❖ 87.3% Water
❖ 3.9% Milk fat
❖ 8.5% Solid not fat
❖ 3.25% Protein
❖ 5.5% Lactose
❖ 0.65% Minerals
❖ 0.13% Acids
❖ Enzymes
❖ Vitamins

1. Milk Fat:
Fat exists in milk in the form of minute globules dispersed. Flavor of milk and its product is
due milk fat. Fat globules vary in size from 2 – 10 micrometer. When milk stands
undisturbed fat globules rise to surface because their specific gravity is less than aqueous
portion. Milk fat is composed of a number of glycerides, esters of fatty acids.

2. Milk Proteins:
Proteins are made up of long chain of amino acids. The major protein present in milk is
casein also known as whey proteins.

3) Milk Sugar or Lactose:

Lactose is made up of glucose and galactose. It is responsible for sweetness of milk. It is a
disaccharide; it comprises 4.8 to 5.2% of milk, 52% of SNF and 72% of whey solids.

4) Vitamin:
Milk contains fat soluble vitamins A, D, E, K and water soluble B complex group of
vitamins.

4
 5) Enzymes:
A number of enzymes are present in the milk. They are analyses, lipase, protease, peroxides,
phosphates.

6) Water:
Water forms the major part of milk i.e. 87%, it forms the medium in which the other
constituents are either dissolved or suspended.

➢ PROPERTIES OF MILK

Aspects Cow Milk Buffalo milk

Acidity 0.13% - 0.14% 0.14% - 0.15%
pH 6.4 - 6.6 6.6 - 6.8
Fat 3.6% - 4.0% 6.5% - 7.2%
Specific gravity 1.028 - 1.030 1.030 - 1.032
Color Creamy yellow Creamy white

➢ FACTORS AFFECTING COMPOSITION OF MILK:

➢ Species of animal
➢ Age of animal
➢ Breed of animal
➢ Interval of milking
➢ Disease or abnormal condition
➢ Stage of lactation
➢ Season
➢ Condition of cow at calving
➢ Administration of drugs or hormones

5
➢ FLOW DIAGRAM FOR MILK PROCESSING

ARRIVAL OF TANKERS
↓
WEIGHING AT WEIGH BRIDGE
↓
SAMPLING, TESTING IN Q.C. LAB
↓
IF OK, THEN ACCEPT IT, ELSE REJECTED
↓
IF ACEPTED, THEN UNLOADED AT UNLOADING DOCK INTO RAW SILOS
↓
WASHING OFF THE TANKERS, AGAIN WEIGHING TO GET TARE WEIGHT
↓
RAW MILK STORED IN SILO’S AT 4o C
↓
CLARIFICATION AT 40 C & HOMOGENISATION AT 60o C
o

↓
PASTERISATION AT 78o C
↓
IMMEDIATE COOLING AND SENT TO STORAGE TANK
↓
FILLER MACHINES AND PACKING
↓
o
STORAGE AT 4 C TILL DISPATCH

6
➢ DIFFERENT STEPS IN THE PROCESSING OF MILK IN THE DAIRY

❖ RECEIVING OF RAW MILK

This is the first step in processing of milk. The milk arrives in the tanker where it is maintained
at a temperature of approx. 4oC. Each of these tankers carries raw milk to the capacity of about 10,
000litre. After checking the gross weight of the tanker, samples of milk are collected to determine
their quality and tanker is accepted only when milk is found to be satisfactory.
Once the milk quality is found to be satisfactory, it is unloaded at the unloading dock. There are 3
such unloading docks. The seal at the mouth of the tanker is opened, the pipeline hose attached and
milk is unloaded. Milk after preliminary filtration, it is stored in silos at 4oC.

❖ SAMPLNG

Sampling of milk from the tankers is done with an instrument known as plunger. Plunger is a
long handle, with a disc attached to one end, with holes in it. Plungers are used for thorough mixing
of the milk inside the tankers by moving the plunger inside it about 20 – 25 times, to ensure through
mixing of milk constituents, else Fat and SNF reading will be incorrect and misleading. Then the
samples are collected from sample points, in three sample bottles- one for adulteration testing,
second for Fat and SNF testing and third for confirmation of improper quality if demanded by
sangh.

❖ SAMPLING PLAN

1. Sampling is done at various stages from raw milk to in-process to packed milk.
2. These samples analyzed for their organoleptic properties, chemical properties and
microbial properties.
3. Sampling of these milk samples has to be done accurately so that the testing carried out
in lab are not misleading and give their accurate results.

❖ CHLLING

There are about 8 storage tanks & 24 filer machines. Cleaning of storage tank is done manually,
from inside with caustic, detergents & water. Crate washing is done on a conveyor belt, on which,
crates are placed inverted, and pass through a chamber, inside which cleaning takes place with plain
water under pressure from both sides and crates are thoroughly washed from inside and outside.
This conveyor then moves ahead. Where crates are again inverted and packed milk pouches are
placed inside these and it moves towards cold storage. Here crates are lined up, and stored at less
than 4oC until dispatch late in the evening. About 20 pouches of 500ml each and 10 pouches of
1litre each can be contained in the crates.

❖ CLARIFICATION

Milk contains many unwanted constituents such as dust, dirt, hay, insects, etc which enter into
milk due to improper handling. These not only hamper the quality and shelf life of the product but
also make the sight of product very unacceptable.

7
The objective of is to improve the aesthetic quality of milk by removing visible foreign particles by
principle of centrifugal sedimentation. Clarification is accomplished using clarifiers working on the
principle of centrifugation; it is best achieved when milk is at 40oC.

❖ HOMOGENIZATION

In this process, milk under pressure is suddenly released, resulted in fat globules of smaller size
which are distributed at equidistance distance within the mass of the milk. This is attained in two
stages: in first stage fat globule membrane into 1000s of small particles, and in second stage it is
increased in whitening power, mouth feel, and viscosity. Milk is rich in fat, these fat globules forms
clumps together and rise to the top due to their lighter density forming a layer on surface. The
purpose of homogenization is to break these fat globules to such an extent that they can no longer
form clumps and rise to the surface. It ensures uniform mixing of fats in milk thereby giving it a
creamy consistency throughout. Homogenization consists of high pressure pump which forces milk
at high pressure through a narrow opening between the homogenization valve and its seats.
Homogenization is done at 60 o C.

❖ PASTEURIZATION

The term Pasteurization was coined by Louis Pasteur of France who demonstrated that heating
wine to a temperature of 50 to 60 o C killed organism and led to increased preservation.
Pasteurization of milk is defined as a process of heating each and every particle of milk to any
temperature time combination so as to ensure elimination of most pathogenic microorganism.
It is generally accomplished using plate heat exchangers. These works on the principle of heat
exchange between two bodies, where in one liquid gets heated by absorbing heat from the hot body
in turn the hot body cooling down due to the loss of heat. This results in the conservation of energy.
Here, milk s pasteurized by heating it into temperature of 78 o C and holding it at that temperature
for 20 sec. however the most important point is to remember pasteurization is not sterilization, as it
does not ensure the removal of all the microorganisms present in the milk. Immediately after
pasteurization milk is chilled to a temperature below 5 o C.
These results in temperature shock to any surviving microorganisms and further ensure it’s
killing or retarded growth. After chilling milk is stored in silos at 4 o C. specific silos are used for
specific variety of milk.
After pasteurization milk is taken to storage tank, these tanks are also used for particular
type of milk. This storage is connected to filler machines, these are Form Fill Seal machines which
form milk pouches, fill the desired quantity of milk and seal the pouches. These filled pouches are
stored in cold storage at a temperature of about 0 to 4 o C.

8
➢ PREPARATION OF CHEMICAL REQUIRED IN THE ADULTERATION TESTS:

1. Phenolphthalein solution:
1gm of phenolphthalein powder +100ml Alcohol +100ml Water

2. Salt solution:
I. 0.1341gm AgNO3 in 100ml distilled water.
II. 10gm K2CrO4 in 100ml distilled water.

3. Urea reagent:
16 gm p-dimethylamino benzaldehyde + 900ml Absolute alcohol+ 100ml conc.HCl.

4. Starch reagent:
1gm Iodine +1gm potassium iodide,dissolved in 100ml absolute alcohol.

5. Glucose reagent:
1ml Acetic acid + 100ml distilled water +6.5gm cupric acetate.
Phosphate molybdate solution.

6. MBRT solution:
Stock solution:
19mg methylene blue (dye) +200ml distilled water.
95mg methylene blue (dye) +1000ml distilled water.

Working solution:
1stock solution: 3 distilled water.

7. n/4 HCl solution:

10ml Conc.HCl +480ml distilled water.

8. Flush concentrate:
10ml Flush conc. +1000ml distilled water.

9. Buffer solution substrate:

Buffer solution:
3.5gm of anhydrous A.R. Na-carbonate &1.5gm of A.R. Na-bicarbonate dissolved in water
&made up to 1liter.
Substrate: p-Nitro-phenyl disodium orthophosphate.

Buffer substrate solution:

Transfer 0.15gm of substrate in to 100ml measuring flask. Add buffer solution up to the
mark, mix it. Solution kept in refrigerator.

9
➢ QUALITY CONTROL SECTION

❖ ADULTERATION TESTS:
Adulterants like neutralizers, urea, salt is added to increase keeping quality of milk
whereas, starch and sugar is added to increase consistency or SNF of milk, if diluted with
water. We can also detect what quality of water has been used for adulterating or diluting
the milk.

❖ DETECTION OF SODA TEST /NEUTRALIZERS:

Soda is added to maintain the acidity. Addition of soda neutralizes the developed
acidity due to staleness or improper handling. Soda is added to milk to increase its keeping
quality and preserved it for longer period if it is of sub standard quality.

Aim - To detect presence of caustic soda in milk and hence check it for adulteration.

Procedure-
5ml milk +5ml alcohol +4 drop rosalic acid shake well. Observe the color and see if there
are any flakes in it. If necessary, invert the test tube and observe the flakes.

Observation and conclusion:

If orange coloration and curdling, or flakes observed, then test is –ve if pinkish color and no
curdling then test is +ve.

❖ DETECTION OF UREA:

Aim: To detect presence of urea in milk.

Procedure:
2ml milk + 2ml urea reagent, shake well observe the colour.

Observation and conclusion:

If faint yellow coloration then test is –ve.
If dark yellow color, then test is +ve.

10
❖ DETECTION OF STARCH:

Aim: To detect presence of urea in milk.

Procedure:
3 ml milk, boil it on flame, cool +3 drop starch reagent shakes well and observe the colour.

Observation:
If coffee color then –ve.
If blue color then +ve.
If dark brown colour, then maltodextrin present.

❖ DETECTION OF SALT:

Aim: To detect presence of salt in milk.

Procedure:
5ml salt reagent 1 +1ml milk +3 drops salt reagent 2.

Observation:
If red color, then test is –ve.
If yellow color then test is +ve.

❖ DETECTION OF SUGAR:

Aim: To detect presence of sugar in milk.

Procedure:
15ml milk +1ml conc. HCl +pinch of resorcinol powder + keep in boiling water bath for 5
minutes. Remove from water bath, and observe the color.

Observation:
If white color then test is –ve.
If red color then test is +ve.

11
➢ OTHER TESTS FOR DETECTION OF QUALITY OF MILK

❖ ACIDITY:
Aim: to estimate the acidity of milk, as %of lactic acid.

Procedure:
Take 10ml milk +10ml water in beaker, add 1ml phenolphthalein as indicator in beaker and
titrate it against N/9 NaOH till end point faint pink colour.
STD reading: 1.3

Calculation: B.R./Volume of sample.

e.g. B.R.=1.3
%acidity= 1.3/10=0.13%

❖ ESTIMATION OF FAT %IN MILK BY GURBER METHOD

Aim: to estimate the fat % in milk.
Apparatus: 10.75ml pipette, beaker, butyrometer, sulphuric acid , amyl alcohol,centrifuge
machine.

Principle:
When a definite quantity of sulphuric acid and amyl alcohol are added to a definite quantity
of milk, the protein will be dissolved and fat globules will be set free which remain in liquid
state due to the heat produced by the acid. On centrifugation, fat being lighter will be
separated and remain on top as a separate layer.

Procedure:
Pre heat the milk at 420C in hot water bath. Remove from the bath, and mix the milk sample
properly, in a beaker. Pipette out 10 ml conc. Sulphuric acid into a butyrometer + 10.75 ml
milk carefully form side of the tube + 1 ml amyl alcohol put rubber stopper & shake well &
centrifuge at 3000 rpm for 3 minutes. Read off the fat %age.

Reason for using 10.75 ml milk:

Between 2 successive gradations on a butyrometre, volume occupied by milk fat is 0.125

ml.
Hence,wt. of milk fat between 2 gradution = vol.of milk fat*density of the milk fat.
= 0.125×0.93
= 0.11625 gms
Now,
1 graduation = 1%fat
i.e. 1 graduation = 1 gm/100 gm milk
0.11625 gm = 11.625 gm milk
But milk is calculated on volume basis
Equivalent volume = mass of milk/density of milk
12
 =11.625/1.03
=11.28 ml of milk
For Indian milk , 10.75 is the most suitable value.

❖ ESTIMATE OF SOLIDS-NON-FAT (SNF) OF MILK

Adjust the CLR of the densitometer to 1.0000 @ 210 C using D/W.

After removing water from injection points, feed milk sample into the densitometer
carefully avoiding air bubbles to get correct lactometer reading at 210 C.

Take CLR and calculate % SNF using the formula:

%SNF = CLR/4 + (0.2* FAT%) + 0.36

❖ BUTYROREFRACTOMETER READING (B R Reading):

Aim: To estimate the butyrorefractometer reading of milk

Principle:
Procedure: This estimation is usually done after fat estimation. The butyrometers are made
to stand in inverted position in the stand, so that the separated fat layer is carefully taken
into a 1 ml pipette by capillary action, and is placed by lightly blowing it on to the prism of
the butyrorefractometer. It is then shut, and reading is taken as %age.

❖ METHYLENE BLUE REDUCTION TIME (MBRT TEST)

This test is performed to keep check on the load of live microorganisms present in the
milk. This is a dye reduction test. In this test the rate at which the dye gets decolorized gives
the quality of milk. The colored dye showed a change in its redox potention resulting in a
change from colored state (blue) to colouredless state (white). Dye reduction tests are
relatively simple and give results within 2 to 3 hours. These results are reliable and
reproducible. Hence, they are used as a rapid method to determine milk quality.
MBRT is done for milk samples from silos and storage tanks nearly 2 times in each shift.
This is one to ensure that processing conditions have been properly followed and that there
is on dexcessive microbial load in milk resulting in its faster spoilage.

Aim- To check the microbial load of pasteurized milk.

Principle- methylene blue in color when in the oxidized state. as microorganisms start
growing in it they utilize this oxygen for their growth and metabolism. Due to this
methylene blue gets reduced. Under reduced conditions, the dye become colorless. Faster
the rate of decolourization, greater the microbial load and lower the quality of milk.

13
 Procedure:

1. Take 1ml of MBRT working solution in a clean and dry sterilized test tube.
2. Add 10ml of milk in it.
3. Mix the contents thoroughly by putting rubber stopper.
4. Incubate at 370C IN serological water bath.
5. Observe the tube for decolourization every 30 minutes.
Observations and conclusion:
Ideally, the time taken for decolourization should be more than 4 hours.

❖ PHOSPHATASE TEST
Aim: To ascertain the efficiency of pasteurization.
Principle: Raw milk contains phosphatase enzyme. It is destroyed at temperature necessary
for efficient pasteurization. But when milk containing phosphtase is incubated with p-nitro
phenyl disodium orthophosphate, the liberated p-nitro phenol gives yellow coloration under
alkaline conditions. The color is measure of the phosphtase content of milk sample. Hence if
phosphates is present, if the test is positive, it follow that either milk is contaminated with
raw milk after heating, or that heating has not been done properly.
Procedure:
1. Transfer 5 ml of the buffer substrate solution to a tube & bring to 370 C.
2. Add 1ml of the milk sample put the stopper and mix the contents of the test tube by
inverting it.
3. Incubate the tube for 2 hours at 370 C.
4. Prepare one blank from boiling milk of the same type as those undergoing the test &
incubate with each series of the sample.
5. Incubate the sample for 30 minutes & read the color.
6. Place the blank on the left hand ramp of the comparator stand, so that it comes under the
color standards and test sample on the right hand ramp so that it is viewed through the
central aperture of the disc.
Revolve the disc until the sample is matched.
7. Reading falling between 2 standards is estimated recorded by affixing a plus or minus
sign to the nearest standard.
8. After a further 90 minutes of incubation, remove the test tubes from the water bath &
mix them well by graded inversion and read the color as before.

Observation and conclusion:

If the color of the solution becomes white, it indicates a positive test

If the color remains unchanged, it indicates a negative test

14
➢ Preparation of buffer substrate solution:

❖ Buffer solution:
3.5 gm anhydrous A.R. (analytical reagent) sodium carbonate & 1.5 gm of sodium
bicarbonate dissolved in water and made upto 1 liter .
Substrate: p-nitrophenyl disodium orthophosphate.

❖ Buffer substrate solution:

Transfer 0.15 gm of the substrate into a 100 ml measuring cylinder add buffer solution upto
the mark, and mix it.
Keep the solution in fridge for 1 week.

➢ KEEPING QUALITY TEST( CLOT ON BOILING TEST):

Aim: To assess the keeping quality of milk at various stages by clot-on boiling test

Principle:
The organoleptic tests for determining the quality of the milk is not very reliable. Milk
which has developed high acidity clots on boiling.

Procedure:
1. Take about 1 ml of the milk in a clean test tube.
2. Heat it directly on the flame, by continuous shaking for about 2 minutes.
2. Immediately observe for curdling. For confirmation, empty the contents and lightly rinse
the tube, and observe the bottom of the tube for any flakes.

➢ DETERMINATION OF PROTEIN IN MILK BY FORMAL TITRATION

Aim: to determine the % of protein in the sample of milk by formal titration.

Apparatus: pipette – 10 ml,2 ml,1 ml,graduates burette – 10 ml, Erlenmeyer flask – 100 ml.
Reagents: neutral formalin, sat.potassium oxalate solution, N/10 NaoH, phenolphthalein
indicator.

Principle: When formaldehyde is added to milk which was previously titrated against
standard alkali to the end point of an indicator like phenolphthalein it binds the amino group
of the milk and release an equivalent amount of protein which would be titrated against the
same end point. The amount of alkali used in the second titration is a measure of the amino
gp. Originally present in the proteins.

15
 Procedure:

1. Pipette 10 ml of well mixed sample of milk into a 100 ml flask.

2. Add 5 drops phenolphthalein indicator.
3. Add 0.4 ml sat.pot.oxalate and keep it aside for 2-4 mins without disturbing aside
for 2-4 min.
4. Titrate the milk against standard alkali N/10 NaoH solution.record the volume(V1)
5. Add 2 ml formaldehyde in the same solution, than titrate against alkali & calculate.

Calculation:

Volume of N/10 NaOH reading by 10ml of milk treated with formaldehyde=’V’ ml.
% of protein =V *1.7(1.7 in dymes constant)

➢ TEST FOR HOMOGENISATION

Solution preparation: 1ml milk sample + 10 ml EQA solution +250 ml distilled water mix
well

Procedure:
1. Take 10 ml distilled water in cuvette & adjust absorbance – 0.000
2. take above prepare solution in cuvette & observe absorbance.
3. Note down absorbance.
4. Calculate the fat % of milk sample sample in beutrometer.
5. With the help of chart calculate the homogenization of milk.

16
➢ CURD

Curd or dahi ,as it is popularly known in India, is a product by action by action of

microorganism on milk, which has been pasteurized, and standardized it is made by adding a
mother culture lactobacilli to milk and letting it stand undisturbed at room temperature (370C) for 5
hours. Lactic acid bacteria have a fermentative action on carbohydrate. Component of milk, and
causes gas formation, whey separation. The brand name for Mahanand curd is “Mast Dahi”. The
specialty of this product is its firm , unbroken and uniform, solid like consistency, with no visible
whey separation, and glossy appearance, clean mouth feel, and no distinct after taste. The acidity of
product is highly crucial aspect and is carefully controlled, by checking it into the lab, and efforts
are made to maintain it at the rate not more than 0.65% while dispatching it in the market. So that,
by the time it reaches the consumer, it doesn’t become sour another important aspect that need to be
consider here, is that, t, the standard of dahi should not be very different from that of the milk used
for the preparation. For eg.fat% and other constituent of dahi should not alter significantly, only
lactose gets converted in to lactic acid by lactic acid fermenting bacteria.
For this reason, quality check is done at every stage in the entire process, not only for curd, but
for every product, including milk. For eg. Milk after standardization and addition of culture, is
check for fat% and SNF%. Fruit pulp is added to dahi to make it more palatable.

Composition of dahi:

Water- 85-88%
Fat- 5-8%
Protein- 3.2-3.4%
Lactose- 4.6-5.2%
Ash- 0.7%
Lactic acid- 0.65-0.73%

Organoleptic properties:

Color: yellowish creamy white (Cow Milk)

Creamy white (Buffalo Milk)
Appearance: smooth glossy surface, creamy layer on top. Free from blemishes

Flavor: mild, pleasant smell, clean acid taste.

Body: soft and firm, free from gas holes and whey pockets.

17
FLOW DIAGRAM FOR MANUFACTURE OF MAST DAHI

Standardization of milk to 4.7% fat, and 9.5% SNF

↓
Homogenization (176 kg/sq.cm.) & Pasteurization @ 900 C for 15 sec.
↓
Cooling to 22-250 C
↓
Addition of mother culture-0.3% (acidity 0.65%) and proper mixing
(streptococcus lactic/lactobacillus bulgaricus)
↓
Filling in 100 gm, 400 gm cups and Sealing
↓
0
Incubation at 37 C for 5 hours (@ pH 5.5)
↓
Transfer Dahi to cold room (40 C for 3 hours)
↓
Bulk packing
↓
Dispatch (acidity maintained at not more than 0.65%)

For sweet dahi For sour dahi

Streptococcus lactis Streptococcus lactis
Streptococcus diacetyl lactis Lactobaccilus bulgaricus
Streptococcus cremoris Streptococcus thrrmophilus
Acidity(maximum) 0.70% Acidity(maximum)1.0%

Application and uses:

Curd is not only manufactured for selling commercially, but also for also for converting in
to many other products like lassi, chaas, shrikhand.

Organoleptic testing:

Taste: slightly sweetish

Appearance: glossy
Color: white
Odor: no particular smell
Mouth feel: sandiness
Aftertastes: clean
Consistency: uniform
Body texture: thick
Whey separation: absent

18
QUALITY CONTROL OF DAHI

Estimation of acidity as % lactic acid in dahi:

Aim: To calculate % acidity in dahi.
Procedure:
Take approximately 1 gm dahi , carefully scooping out from the center of the cup, in a clean, dry
beaker. Note down the weight. Take a clean glass rod, and mix it properly to get a homogenous
sample. Add 10ml distilled water, 1ml phenolphthalein, and titrate against 0.1N NaOH.
After end point is achieved, note the burette reading, and calculate % acidity.

Calculation: B.R./ wt. of the sample.

19
➢ SHRIKHAND

Shrikhand means the product obtained from chakka or skimmed milk. Chakka to which milk,
fat is added. It may contain fruit, nuts, sugar, cardarnom, saffron & other spices. It shall not contain
any added coloring & artificial flavoring substances.

Composition of Shrikhand :
Total solid percent by weight = not less than 58
Fat (on dry basis) weight = 8.5 minimum
Milk protein = not less than 9
Acidity = 1.4 maximum
Sugar = 72.5 maximum
Total Ash = 0.9 maximum

FLOW DIGRAM FOR PRODUCTION OF SHRIKHAND

Dahi
↓
Hang in muslin cloth

↓
Slowly shake it vertically, drain off the whey- 4-5 hours

↓
Chakka + sugar 70-90%

↓
Mixing and blending – planetary blender – 5-6 minutes

↓
Keep aside – 11/2 hours (sugar dissolve)

↓
Addition of flavor

↓
nd
2 blending

↓
Salt addition

↓
3 blending – 5 mins
rd

20
 ↓
Packaging- 100 gm cups

↓
Storage @ -15 to -170 C

TESTING OF SHRIKHAND:

Organoleptic test:

Taste: sweetish sour

Mouthfeel: sandiness

Color: white/yellow

Texture: smooth

Flavor: fruity

Seeds: present

Consistency: thick (semi-solid)

Chemical tests:

1) Moisture estimation:
Weigh the empty aluminium dish, take approximately 2.5 gm of the sample, and spread it
out evenly, again weigh it accurately, and note it down. keep it under the Sartorius moisture
balance, for about 30 minutes or till it dries off completely, and turns brownish, giving a typical
odour. Weigh it again, and subtract this weigh from the dish + sample weight, giving a value as
moisture loss from the sample. This value is then multiplies by 100 and divided by the sample
weight.

2) Fat:
Procedure:
Take exactly 3gm of the sampe in aches butyrometer. Add 10 ml of conc. sulphuric acid, add
1ml amyl alcohol. Put the stopper and mix well. Centrifuge @ 3000 rpm for 3 minutes. Read off
the fat percentage.

3) Titratable acidity:
Procedure:
1. Take app. 1gm of the sample in a clean dry beaker. Mix well with a glass rod.
2. Add 10 ml distilled water, and 1ml phenolphthalein; again mix well with a glass rod.
3. Titrate against 0.1N NaOH till faint pink end point
4. Note the reading as (A) ML OF NaOH spend from the burette.
21
5. Calculate the % acidity as follow:
Acidity%= 9AN/W

Where,
A=Volume of NaOH spent from the burette.
N=Normality of NaOH.
W=Wt. of sample.

22
➢ CHASS

FLOW DIAGRAM FOR PRODUCTION OF MASALA CHASS

Pasteurized milk

↓
Inoculation

↓
Setting of curd

↓
Breaking of curd

↓
Water addition

↓
Homogenization & blending

↓
Addition of salt, spices, mixing

↓
Storage at 400C -12 hours

↓
Filtration, packaging(pouches and cups)

↓
Cold storage &dispatch.

23
TESTING OF CHASS

Organoleptic testing:

Color: off white

Mouthfeel: sandiness

Consistency: thick, non uniform

Chemical testing

1) Titratable acidity
Procedure:
1. Weigh app. 1gm of the sample in a clean dry beaker.
2. Add 10 ml water and mix the contents properly with aglass rod
3. Add 1ml phenolphthalein
4. Titrate against 0.1 N NaOH till faint pink end point.
5. Calculate % acidity.

2) SNF (Solid –non-fat)

Procedure:
1. Adjust the CLR of the densitometer to 1.000 @ 210C with d/w.
2. Remove the water from injection point.
3. Feed milk sample to densitometer to avoid air bubbles and get correct reading
4. Take the reading and calculate the SNF as follow:
SNF=CLR/4+0.21* fat+0.36

3) Fat %
Procedure:
1. Take 10.75ml chaas in butyrometer delivery through neck of tube
2. Add 10ml of Sulphuric acid and 1ml Amyl alcohol
3. Put the rubber stopper and shake it well
4. Centrifuge it at 3000 r.p.m. for 3 min.
5. Read fat %.

4) Total solids
Procedure:
1. Take lactometer reading through density meter and fat content through Gerber method
2. Then calculate total solid as follows:
%TS = CLR/4 + 1.2 X FAT+ 0.5

24
➢ LASSI

FLOW DIAGRAM FOR PRODUCTION OF LASSI

Pasteurized milk
↓
Inoculation
↓
Setting of curd
↓
Breaking of curd
↓
Water addition
↓
Addition of sugar
↓
Homogenization & blending
↓
Storage at 400c-12 hrs
↓
Filtration and packing (cup or pouches)
↓
Cold storage & dispatch

Organoleptic test

Color: sweet

Flavor/odor: free from objectionable flavor/odour

Taste: sweet /sour

Consistency: uniform

CHEMICAL TESTING OF LASSI

1. Titrable acidity.
Procedure:
1. Weigh approx. 1gm of lassi in clean dry beaker
2. Add 10ml water and mix the content properly with glass rod
3. Add 1ml phenolphthalein
4. Titrate against 0.1N NaOH till faint pink end point.
5. Calculate % acidity

25
2. Fat %
Procedure:
1. Take 10.75ml lassi in butyrometer delivery through neck of the tube
2. Add 10ml of Sulphuric acid and 1ml Amyl alcohol
3. Put the rubber stopper and shake it well
4. Centrifuge it at 3000 r.p.m. for 3 min.
5. Read fat %.

26
 ➢ STERILED FLAVOURED MILK

FLOW DIAGRAM FOR PRODUCTION OF STERILE MILK

Standardize milk
↓
Pasteurization (at 780C)
↓
Homogenization
↓
Mixing of sugar
↓
Addition of colored flavored
↓
Packing in bottle
↓
Sterilization (1200C for 20min)
↓
Labeling
↓
Storage (at room temp.)

Organoleptic test:

Color: as per color added

Flavor: as per added

Odour: no effective flavor

Taste: sweet

Consistency: uniform

Turbidity test:

Aim: to check the efficiency of sterilization in the preparation of sterilized milk.

Principle: albumin in milk is completely denaturated at sterilization.

Albumin in milk is completely precipitated if milk is heated for a short time at 1000C. therefore if
the filtrate obtained from a sample of milk from which other protein have been patted by suitable
agents shows sign of turbidity on heating it follows that the milk is not been sterilizes properly.

27
Why Ammonium sulphate is used?
Because of the acidic nature of ammonium sulphate the soluble proteins as(whey protein) become
insoluble as they completely denature on sterilization, on filteration the insoluble particle cannot
pass through filter paper therefore no turbidity or no ppt is obtained which signifies proper
sterilization.

Procedure:
1. Take 4gm ammonium sulphate in dry beaker.
2. Add 10ml sterile milk, stir with glass rod.
3. Filter this solution through filter paper
4. Take filtrate in test tube & boil it,& observe.
Observation:
If turbidity is observed then milk is not properly sterile.

CHEMICAL TESTING OF STERILED FLAVOURED MILK

Titrable acidity.
Procedure:
1. Weigh approx. 10ml of sterile milk in clean dry beaker
2. Add 10ml water and mix the content properly with glass rod
3. Add 1ml phenolphthalein
4. Titrate against 0.1N NaOH till faint pink end point.
5. Calculate % acidity

Fat %
Procedure:
1. 10.75ml sterile milk in butyrometer delivery through neck of the tube
2. Take Add 10ml of Sulphuric acid and 1ml Amyl alcohol
3. Put the rubber stopper and shake it well
4. Centrifuge it at 3000 r.p.m. for 3 min.
5. Read fat %.

28
➢ PANEER

FLOW CHART FOR MANUFACTURING OF PANEER

RECEIVING MILK
↓
FILTRATION
↓
COOLING (70o)
↓
ADDITION OF COAGULANT AND CONTINUOUS HEATING
↓
DRAINING OF WHEY
↓
PANEER MASS
↓
COOLING
↓
PACKING IN POUCHES
↓
STORAGE (18o)

ORGANOLEPTIC TESTING

Color – White

Texture – Rough

Taste –Slightly sweetish

Mouth feel – Sandy

Odour – Fresh

Appearance – No glossiness

CHEMICAL TESTING

Preparation of sample:
1) MOISTURE
Break 1 cube of the paneer sample, and mesh it with a spatula and macerate it properly so
that no granules remains and a homogenous mixture is obtained.

29
2) TITRABLE ACIDTY

Procedure:

1) Weigh app. 1gm of macerated paneer in a clean beaker

2) Add 10ml of water and mix the contents properly with a glass rod
3) Add 1ml phenolphthalein
4) Titrate it against 0.1N NaOH till faint pink end point
5) Calculate % acidity

3) FAT %

Procedure:

1) Take 3gm, of sample in the butyrometer delivery through neck of the tube
2) Add 10ml of sulphuric acid and 1ml of amyl alcohol
3) Put the rubber stopper and shake it well
4) Centrifuge it at 3000 r.p.m. for 3 minutes
5) Read fat %

4) TOTAL SOLIDS

Procedure:

1) Take a clean dry aluminum dish and weigh it, tare the weight
2) Take about 2.5gm paneer in it and again weigh it accurately
3) Keep the dish with sample under sartorius moisture balance till sample dries completely.
4) Weigh the dish after complete drying.

Cow Milk Paneer Buffalo Milk Paneer

Moisture % 52-54 50-52

Total Solids % 45-47 45-47
Proteins% 16-19 13-15
Lactose% 2.0-2.2 2.2-2.4
Ash% 2.0-2.3 1.9-2.1
Fat % 24.0-26.0 28-30

30
➢ GHEE
FLOW CHART FOR PRODUCTION OF GHEE

Receiving milk
↓
Filtration
↓
Separation of cream
↓
Inoculation & incubation
↓
Heating of ripened cream in ghee vat
↓
Cooling to 50o C
↓
Filtration
↓
Ghee
↓
Packing
↓
Storage at room temperature

Determination of moisture:

1) Weigh accurately about 10gm of homogenized ghee sample in a previously weighed beaker.
2) Keep this beaker in an oven maintained at 1050C for 2 ½ to 3 hrs.
3) Remove from the oven & cool in desiccators &weigh again.

Calculation:
100×wt.of loss of moisture
% of moisture by mass= wt.of sample taken

Determination of free fatty acids.

1) Weigh accurately about 5 to 10 gm of sample in a previously weighed conical flask.

2) Add 50ml of neutral alcohol, warm till the fat dissolved in alcohol.
3) Cool and add few drop of 1% phenolphthalein indicator & titrate against 0.1N NaOH till
pink color appears.

Calculation:

Titre reading ×2.82

FFA = wt.of sample taken

31
Boudin’s test:

1) Take 5grm of the melted ghee in 20ml measuring cylinder with stopper & add 5ml of
conc.HCl & 0.4ml of furfural solution.
2) insert the glass stopper & shake vigorously for about 2min. Allow the mixture to separate. If
pink colour develops in the acid layer,the test is +ve and indicates the presence of sesame
oil.

Confirmatory test:

Add 5ml of distilled water to the measuring cylinder if pink colour still persists. Presence of
sesame oil is confirmed.

Butyro-refractrometer Reading (B.R.)

1) Clean the prism with cotton, wetted with alcohol &petroleum ether mixture(1:1). Dry the prism.
2) Place a drop of test sample on the lower part of prism & lock it.
3) Adjust the instrument & lens as per the conditions mentioned in the procedure & note down the
reading at room temperature.
4) Convert this reading to refractive index at 400C using reference table.

Calculation:

Refractive index at 400C = R+K(T1-T)

Where, T1=Temp. at which the reading is taken i.e. room temp.
R=Refractive index at ‘T’ degree centigrade
T=Specific temp. 400C
K=0.000365

Determination of soluble & insoluble volatile acids (Reichert-Meissl & Polenske value)
Procedure:

1) Weigh accurately 5.00grms of the ghee sample in a polenske flask.

2) Add accurately 2ml of 50% NaOH & 22 ml of glycerin.
3) Saponify the above mixture on a burner flame.
4) Add 93ml hot boiling distilled water, while the above saponified mixture is still hot & take care
so that mixture inside the flask does not spatters.
5) Add 6 to 7 glass beads to the above flask to avoid bumping of the content in the flask.
6) Assemble the polenske flask with the distilled apparatus.
7) Add 50ml of dil.sulphuric acid in to the flask.
8) Fix one end of the still head to the flask & the other end to the water condenser.

32
9) Heat the flask without boiling the content until the volatile acid is completely melted & a brown
ring appears on the surface of the content of the flask. Then increase the flame & distill 110ml
in between 19 to 22 mins.
10) Keeps the water flow flowing in the condenser at a sufficient speed to maintain the temp. of the
issuing distillate between 18-210C.
11) When the distillate reaches 110ml mark, remove the flame &replace the 110ml flask by a test
tube of 25ml capacity to catch the draining.
12) Stopper the 110ml flask & place it in to water at 150C for 10min. so as to immerse the 110
mark.
13) Remove the flask from the water, dry from outside. Mix the distillate by slightly tilting the flask
avoiding wetting the stopper with insoluble acids.
14) Filter through filter paper no.4 collect 100ml in dry conical flask & retain the solution for
titration.(RM value).
15) Detach the still head wash the condenser with three simultaneous 15ml portion of cold distilled
water. Discard the washings.
16) Dissolve the insoluble acids by 3 similar washings of the condenser 110ml flask & filter with
15ml of neutralized ethanol. Collect the solution in a conical flask & retain the solution in a
conical flask & retain the solution for titration(PV)
17) Rechert-Meissl or soluble volatile acid value titrate 100ml of the filtrate containing insoluble
volatile acids against 0.1N NaOH using phenolphthalein indicator till the appearance of pink
colour. let the reading be T1
18) Polenske value or insoluble volatile acid value:
Titrate the alcoholic solution of the insoluble volatile acids as in no.1. let the reading be T2

Calculation:

RM Value = 1.1 × (T1-T)

Where, T= blank reading
PV Value = T2-T

33
➢ BACTERIOLOGY

Nearly all changes which take place in the flavor and appearance of milk after it is drawn from
the cow are the result of the activities of microorganisms. Of these, the most important in dairying
are bacteria, moulds, yeast and viruses- the first one predominating. In the dairy industry
considerable effort is expended in controlling microbes which causes spoilage. The greater bacterial
count in milk i.e.- the greater the number of bacteria per ml of milk, the lower is its bacteriological
quality.
In milk and its products, the spherical and cylindrical forms are predominant. Most bacteria
vary from 1-5 micron in size. Some bacteria also form spores, which are tough resistant bodies
within the bacterial cells. Spores which are tough resistant bodies within the bacterial cell. Spores
when placed in an environment favorable to growth, form new vegetative cell. Spore forming
bacteria cause trouble in the dairy industry of their resistance to pasteurization and sanitization
procedure. Some microorganism brings about desirable changes thus proving to be beneficial while
others are present which are capable of causing diseases. These disease causing verities are called
as pathogens.
In microbiology, growth refers to increase in numbers. Milk drawn from healthy cow already
contains bacteria their numbers multiply during production and handling, depending on the
cleanliness of these operations. Subsequently their numbers may grow still further depending on
storage conditions. Microorganisms are capable of growing across a wide range of temperature
from 50 to 850C.

There are various factors influencing their growth such as

1. Food supply
2. Moisture
3. Acidity and pH
4. Availability of oxygen
5. Temperature

Mycobacterium tuberculosis: It is the most severe pathogenic organism present in milk. It

enters into milk as a result of infection of cow itself. This organism is also very heat resistant.
Hence, it is consider as the index organism for pasteurization. Pasteurization will also reduce
microbial load of milk by killing other organisms as well. Coli forms are the other group of
microorganisms capable of causing diseases. These however, may enter as a result of direct
contamination of milk by human beings.
Hence, the microbial tests done are mainly aimed at determining the general microbial load of
milk as well as determining the coli form content in milk.

Hence bacteriological department plays vital role in controlling these organisms. Milk being
extremely susceptible to microbial contamination the microbiological analysis become very
important.

34
PREPARATION OF SOLUTION

Saline solution:

Sodium chloride 9ml + 1000ml distilled water. ( Ph adjust= 3.5)

Ringer solution:

1. Sodium chloride- 9 gm
2. Potassium chloride- 0.42gm
3. Calcium chloride – 0.24gm
4. Sodium bicarbonate- 0.20 gm
5. Distilled water- 1000ml

Potato dextrose agar:

39gm PDA + 1000ml of distilled water or 19.5 gm PDA + 500ml of distilled water, dissolved it.
Sterilize it.

❖ PROTOCOL FOLLOWED FOR MICROBIOLOGICAL ANALYSIS

1) Processed milk samples are collected from each filler, silo and storage tank every day.
2) Water used in the plant for various purposes is also sampled for analysis every day.
3) Swab testing is done once a week. For this purpose samples are taken by rubbing swabs on the
walls of the silos and storage tank.
4) Microbiological analysis is done using pour plate technique.
5) Milk is diluted 100 times by adding 9.9ml saline to 0.1ml milk.
6) 1ml of this dilution is poured along with the media into the Petri plates.
7) The media used are standard plate agar and deoxycholate agar for determination of microbial
load and coli form count respectively.

Standard plate count

This test is done to see the general growth of microorganisms in milk’ it also provides an
index of the general bacterial population and also determines the efficiency of pasteurization. The
media used is plate count agar.

Composition of plate count agar:

Casein enzymic hydrolysate 5.00 grms/lit

Yeast extract 2.50 grms/lit
Dextrose 1.00 grms/lit
Agar 15.00 grms/lit

Final Ph(250C) 7.0 ±0.2

35
Procedure:

1) 0.1ml of milk is diluted with 9.9ml saline.

2) Of this 1ml is taken in sterile Petri dish. About 10-15ml of plate count agar is poured and mixed
well.
3) After allowing to set for 15 minutes, the plate is kept for incubation at 370C for 48 hours.

Preparation:

Add 23.5 gm in 1000ml of distilled water. Boil to dissolve. Sterilize media by autoclaving at 15 lbs
(1210C) for 15 minutes.
Use of agar
It is used for determination of plate counts of microorganisms in foods, water and wastewater.
Critical limit: 32,000 colonies per ml.

Coli form count

It is used to determine the presence of coli forms and their level of presence.
Coli forms come into milk due to human contamination. They are capable of causing severe
gastrointestinal disorders. They may again entry due to fecal contamination of water. The presence
of even a single coli form is an alarming issue and should be controlled with immediate effect. Coli
forms are considered as major hazards in the food industry.

The media used for detection of coli form is deoxycholate agar.

Composition of deoxycholate agar:

Peptic digest of animal tissue 10gm/lit

Lactose 10gm/lit
Sodium deoxycholate 1gm/lit
Sodium chloride 5gm/lit
Dipotassium phosphate 2gm/lit
Ferric citrate 1gm/lit
Sodium citrate 1gm/lit
Neutral red 0.03 gm/lit
Agar 15 gm/lit

Final pH(at 250C) 7.3 ± 0.2

Preparation:

Add 45gm in 1000ml of distilled water. Heat to boil till it dissolves. Do not autoclave.

36
Use of agar:

It is used for direct differential count of coli forms in dairy products and for isolation of enteric
pathogens from rectal swabs, feces and other pathological specimens.

Critical limit : 10 colonies per ml.

❖ MICROBIAL TESTING FOR PRODUCTS

▪ MAST DAHI:

Procedure:
1) Take 4 teaspoon dahi from cup & smash it properly.
2) Take approximately 1gm/1ml from it in 9ml ringer solution(1st dilution)
3) Take 0.1ml for coli form & 0.1 ml for E- coli. In sterile small petry dish. Pour respective
agar and incubate for 24 hrs at 370C.
4) From 1st dilution take 1ml solution and add to 9ml ringer solution &prepare 2nd dilution.
5) Take 1ml from it in sterile big Petri dish for Y/M and pour potato dextrose agar and
incubate it for 48 hours at 370C.
6) Take 1ml from 2nd dilution and add in 9ml ringer solution & prepare 3rd dilution.
Respectively prepare 5th dilution.
7) Take 1ml from it in sterile big Petri dish pour plate count agar and incubate for 48 hrs at
370C.

Limits for microbial count:

Y/M – If Y/M can’t exceed 100 per ml of dahi it indicate poor quality.
Coli form- dahi of good quality should give –ve test.

▪ AMRAKHAND, SHRIKHAND, PANEER, CHAKKA.

Procedure:
1) Take 1gm sample in dry sterile beaker and add 9ml warm ringer solution(1st dilution)
2) Take 0.1ml for coli form & 0.1ml for E-coli in sterile small petri dish. Pour agar and
incubate for 24 hrs at 370C.
3) Take 1ml solution from 1st dilution and add to 9ml ringer solution and prepare 2nd dilution.
4) Take 1ml from 2nd dilution and prepare add to sterile big petri dish add potatodextros agar
and incubate for 48 hrs for Y/M at 370C.
5) Take 1ml from 2nd dilution and add to 9ml ringer solution and prepare 3rd dilution.
6) Take 1ml from 3rd dilution and add to sterile big petri dish pour plate count agar and
incubate for 48hrs SPC count and incubate it for 48hrs at 370C

37
▪ FLAVOURED MILK, LASSI , CHASS

Procedure:

1) Take direct 0.1 ml for coli form and E-coli in sterile small Petri dish and pour agar and
incubate for 24hrs at 370C.
2) Take 1ml sample solution and add in 9 ml ringer solution and prepare 1st dilution.
3) Take 1ml from 1st dilution and add in 9ml ringer solution and prepare 2nd dilution.
4) Take 1ml from 2nd dilution and add in sterile big Petri dish for Y/M, pour potatodextrose
agar and incubate for 48 hrs at 370C.
5) Take 1ml from 2nd dilution and add in 9ml ringer solution and prepare 3rd dilution
6) Take 1ml from 3rd dilution and add in sterile big Petri dish pour plate count agar and
incubate it for 48hrs for SPC at 370C

▪ STERILIZED MILK

Procedure:

1) Take direct 0.1ml sample for coli form & E-coli in sterile small Petri dish. Pour agar and
incubate it for 24hrs at 370C.
2) Take direct 1ml sample in sterile big Petri dish and add potatodextrose agar for Y/M and
incubate it for 48hrs at 370C.
3) Take direct 1ml sample in sterile big Petri dish and add plate count agar for SPC. Incubate it
for 48hrs at 370C

Limits for microbial count:

Less than 6- satisfactory.

More than 6- not satisfactory.

38