Ultrasonic milk analyser__________________________________________________________________
Milkotronic Ltd
LACTOSCAN SLC
MILK ANALYZER
4 characters LED display
Operation manual
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Switching Adapter
• Input:
• Output:
• Output power:
100 - 240 V ~1.6 A max.
50-60 Hz
4.17А min.
+12 V
50 - 65 W
Measurement modes
•
•
•
•
•
•
•
•
•
•
•
cow milk
sheep milk
UHT milk
goat milk
buffalo milk
camel milk
cream
whey
ice-cream mixtures
recovered milk
other
CAUTION!
Keep the switching adapter dry!
Please, read and follow strictly all the instructions in the manual.
Due to continuous improvement in the device, information contained in this manual is
subject to change without notice. Contact the producing company for revisions and
corrections
4, Narodni Buditeli Str.,8900 Nova Zagora, BULGARIA
Phone/Fax: + 359 457 67082
E-mail: office@lactoscan.com
www.lactoscan.com
www.milkotronic.com
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SAFETY INSTRUCTIONS
1. Read this manual carefully and make sure that you understand all the
instructions.
2. For safety purposes the device is equipped with grounded power cable.
If there is no grounded electrical outlet where the device will be used,
please, install such before using the device.
3. Place the device on leveled and stable plate. In case it falls or is
severely shocked it may be damaged.
4. Connect to the electrical network in such a way that the power cable to
stay away from the side for accessing the device and not to be stepped
on.
5. Every time before cleaning the device switch it off and unplug it from
the electrical outlet. The device has to remain unplugged till the
cleaning completion.
6. Do not disassemble the unit in order to avoid possible electrical shock.
In case of malfunction contact your local dealer.
7. Handle the liquids the device works with carefully, following all the
instructions for their preparation.
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PARTS AND ACCESSORIES
In the table below the standard delivery configuration of the milk analyzer is
listed:
№
1.
2.
3.
4.
5.
6.
7.
Description
Item №
Ultrasonic portable milk analyzer
Operation manual
Sample holder
Spare Pipes
12 V DC Power Supply Milk Analyser Cable
Alkaline cleaning product Lactodaily 100 g
Acidic cleaning product Lactoweekly 100 g
pcs
90-1801-0009
1
1
2
2
1
1
1
In the table below the milk analyzer spares and accessories, which are
delivered on customers’ request are listed:
№
8.
9.
10.
11.
12.
13.
14.
Description
a) included in the set:
b) not included in the set (may be
additionally bought):
Item №
Handle
ECS POS Serial Printer
90-1801-0007
12 V Serial Printer Power Supply Cable
RS232 Interface Cable - Milk Analyser –
90-1801-0008
Serial Printer
RS232 Interface Cable-Milk Analyser-IBM
90-1801-0010
PC
Carrying case – plastic
Plug type
pcs
/
1
1
1
1
1
1
1
1. FUNCTION
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The function of the milk analyzer is to make quick analyses of milk on
fat (FAT), non-fat solids (SNF), proteins, lactose and water content
percentages, temperature (oС), freezing point, solids, as well as density
of one and the same sample directly after milking, at collecting and
during processing.
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2. TECHNICAL CHARACTERISTICS
2.1. Working modes characteristics:
The program of the milk analyzer has four working modes.
2.1.1. r1.1 Measurement mode milk / dairy product – first type
2.1.2. r1.2 Measurement mode milk / dairy product – second type
2.1.3. r1.3 Measurement mode UHT milk / dairy product – third type
These modes have been calibrated on customers’ request for 3 milk types
from the following: cow, sheep, UHT, buffalo, goat, camel milk, cream, ice
cream mixtures, whey, recovered milk, etc. before leaving the production
facilities and the text on the display will be for the corresponding types, as is
indicated on page 2 Measurement modes.
2.1.4. r2. Cleaning
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2.2. Measuring range:
Fat .....................................………....
SNF .................................................
Density *........................................…
Proteins.....................................……
Lactose ............................................
Water content ..................................
Temperature of milk…………………
Freezing point**………………………
Solids**……………………………….
……............….from 0.01 % to 20 %
……............……..from 3 % to 15 %
...…….......from 1015 to10 40 kg/m3
.............…………….from 2 % to 7 %
...........................from 0.01 % to 6 %
...........................from 0.0 % to 70 %
…………………..from 1 oC to 40 oC
………….from –0,400 to –0,700 o C
………………...…..from 0,4 to 1,5%
* Density data are shown in an abbreviated form. For example 27.3 have to
be understood as 1027.3 kg/m3. To determine the milk density, write down the
result from the display and add 1000.
Example: result 31,20; density = 1000 + 31,20 = 1031,2 kg/m3
** Measured values for freezing point and solids are printed out.
2.3. Maximum permissible absolute error:
Fat.......................................………...
SNF .............................................….
Density *.......................................….
Proteins ........................................…
Lactose ............................................
Water content................................…
temperature of milk…………………..
Freezing point………………………..
Solids………………………………….
................................………. ± 0.10%
........................................... ± 0.15%
.........….......................... ± 0.3 kg/m3
...............................….. …...± 0.15%
.......…..................................± 0.20%
.......….............................……± 3.0%
………….………………………± 1 oC
…..…………...……........... ± 0.001oC
…………………………....... ± 0.05%
The difference between two consequent measurements of one and the same
milk may not exceed the maximum permissible absolute error. This difference
is ensured when working under correct ambient conditions.
2.3.1 Correct ambient conditions for optimal results of analysis.
air temperature....................……….. ……....................from 10 oC to 35 oC
relative humidity......................…… …..…..................…from 30% to 80%
power supply...................………….. …….............................. 220V (110V)
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Maximum permissible absolute error values in point.2.3 are in dependence
on the correctness of the corresponding chemical method, used for
component content determination. In point 2.3. are used the following
methods: Gerber – for fat, gravimetric – for SNF, Keldhal – for protein. The
boundary for maximum variation of repeatability when the power supply
voltage is from +10 to – 15% from the nominal voltage values (220V) have to
be no more than 0.8 accuracy according point 2.3. The analyzer is used in
conditions free of outer electrical and magnetic fields (except the magnetic
field of the Earth) and vibrations.
2.4. Dimensions:......…….....……………………240/220/100 mm, mass 3,0 kg
2.5. Continuous working time:.........................….....………………..nonstop
2.6. Milk sample volume per one measure:..………………25 cm3 (= 25 ml.)
2.7. Connecting to 12 V DC power supply.
If there is a need the analyzer to work on place without electrical supply
available, then it could be powered by car battery or other 12 V DC external
power supply. Use the 12 V power supply cable (art. number 90-1801-0009,
Parts and Accessories, point 13).
2.8. Connecting to IBM PC.
The milk analyser can be connected to IBM PC using the RS232 interface
cable (art. number 90-1801-0010, p.6 Parts and Accessories, point 10). In
order to make the connection: switch off both the analyser and PC. Connect
the RS 232 cable towards Serial interface (fig. 2, point 9) and towards the
computer. Turn on both analyser and PC. Now the milk analyzser is ready to
communicate with IBM PC.
2.9.Connecting a printer (option).
In order to print out the measurement results, a serial printer could be
connected to the device – for example ESC/POS Serial printer, production of
Datecs or Seiko. The interface connector for the printer is on the rear panel of
the device (see fig.2) – “Serial printer connector”. The printer should be
connected to the “12 V printer output” on the device rear panel, fig.2. Connect
it via cables, delivered by the company-producer. If the printer is connected
directly to the network, then the analyzer and the printer should be connected
to one and the same electrical phase.
Communication parameters: 9600 bps, No parity, 8 bits, 1 stop bit. It’s oneway communication (uses one line) – the analyzer only sends and the printer
only accepts data.
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2. THE ANALYZER AND ITS COMPONENTS
Fig. 1 Front panel
1
2
5
min 15-20mm
from level
3
4
A SCALE 1 : 1
6
5
7
8
1. Handle
2. Program Button
3. Display
4. LEDs
Operation Manual
5. Output pipe
6. Input pipe
7. Start button
8.Hanger
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Fig. 2 Back panel
1 Handle (option)
2. Serial printer interface
3. Serial interface RS232
4. 12 V printer output
Operation Manual
5. 12 V input
6. Power switch
7. Switching adapter
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Fig. 3 Principle working scheme
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Fig.4. Cable Description
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90-1801-0007
12 V Serial Printer Power Supply Cable (Thermal printers type EP-50 see
http://www.datecs.bg)
90-1801-0008
RS232 Interface Cable - Milk Analyser – Serial Printer standard for EP-50 (for
other Printer, see printer’s manual)
Milk
2. TxD
Analyser
3. RxD
DB 9-pin
5.GND
male
Serial
2. Receive Data (RxD)
Printer
3. Transmit Data (TxD)
DB
9-pin
5. Signal Ground (GND)
male
90-1801-0010
RS232 Interface Cable - Milk Analyser – IBM PC
2. TxD
3. RxD
5.GND
Milk
Analyser
DB 9-pin
male
2. Receive Data (RxD)
PC
DB
9-pin 3. Transmit Data (TxD)
5. Signal Ground (GND)
female
90-1801-0009
12V DC Power Supply Milk Analyser Cable
1. GND
2. No connection
3. No connection
4. 12V DC
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4. ANALYZER INSTALLATION
4.1. Put the analyzer on the working place, providing good ventilation and
not in the vicinity of heat providing devices or sources.
4.2. Check if the switch “Power” (fig.2, 15) is in "0" position and that the
outlet voltage complies with the voltage indicated on the rating plate of the
analyzer. Connect the power supply cable (fig.2, 18) to the electrical outlet.
4.3. Set the switch “Power” to "I" position. For a short time the version of the
analyzer’s software is shown on the display (fig.1, 2), then the modes r1.1,
etc. and at the end after about 5 minutes, the serial number of the analyzer
appears. When the device is ready for work a beep can be heard and the
indicator r1.1 lights up. The information, indicated during this procedure
identifies the device.
If in the process of exploitation there is a need to ask a question the
company-producer, you have to send the data from the analyzer, written on
the display during the above described initialization procedure.
4.4. If you wish to work in the other working mode press and hold the button
PROGRAM (fig.1, 1) on the front panel of the device. Then, without releasing
the button PROGRAM, put the sample-holder (fig. 1, 7) on its place. The
possible operation modes will be displayed “r1.1"- mode 1; "r1.2"- mode 2;
“г1.3”-mode 3; ”г2”-cleaning mode. Release the button PROGRAM when the
indicator shows the desired mode of operation. The device starts the chosen
mode.
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5. MAKING ANALYSES
5.1 The milk sampling.
When taking samples follow the below mentioned standard procedures to
avoid any air enclosure in the milk.
5.1.1. Before taking the sample from a quantity of milk that has to be
qualified, the milk has to be stirred with special mixing tool.
5.1.2 Taking a sample from vessels, which do not allow good stirring of milk
is not acceptable. First the milk has to be poured in standard milk measuring
vessel and stirred several times with the floating level indicator. If there is no
floating level indicator, then the milk has to be poured 4-5 times from vessel
to vessel before taking the sample.
5.1.3. Taking a sample has to be done with special tube made from
aluminum, stainless steel or glass with inner diameter of 8-10 mm. The
sample must be at least 100-150 ml.
5.1.4. If transportation of the sample to a laboratory is necessary then it has
to be preserved with potassium bichromat or transported in a cooling bag.
5.1.5. Prepare the milk samples at least two hours after milking in order to
avoid any air in the samples.
5.1.6. Just before making measurement with the milk analyzer, pour the
sampling milk from vessel to vessel 4-5 times. Pour it in the plastic sampleholder (fig.1, 7) included in the set of the analyzer and start measurement.
5.1.7. Before analyzing the milk sample check whether the acidity of the milk
is lower than 22o T.
5.1.8. If the sample has been cooled leading to butter on the surface, it has to
be heated to 40 oC and then cooled to 20-25 oC, in order to distribute the fat
in an evenly way before the measurement takes place.
5.2. Making measurement
5.2.1. For working with the modes r1.1, r1.2 and r1.3 the sample has to
be well stirred before pouring it in the sample-holder.
Put the sample-holder with the required quantity of milk in the recess (fig.1, 6)
of the analyzer in such a way that the starting button (fig.1, 5) is activated.
The analyzer sucks the milk, makes the measurement and returns the milk in
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the sample-holder. The values of the first milk sample achieved after the
required start up procedure with distilled water have to be ignored. Make a
second measurement with a fresh sample of the same milk, so not using
again the first milk sample that already passed the analyzer. From now on
one measurement per sample is sufficient during the whole series of analysis.
5.3. Displaying the results
5.3.1. When the measurement is finished, the sample returns in the sampleholder and the display (fig. 1, 2) shows consequently the results for fat
(FAT%), nonfat milk solids (SNF %) and density (DENSITY).
- When fat is displayed the diode “FAT%” lights (fig.1, 2)
- When nonfat milk solids are displayed the diode “ SNF %” lights (fig.1, 3)
- Both diodes “ DENSITY” light (fig.1, 3) when the density results are
displayed
When there is a content of water in the milk both diodes across ADD.
WATER light permanently.
If you need the results of proteins, lactose and water to be displayed, press
the button PROGRAM (fig. 1, 1) for 1-2 seconds and release without
removing the sample-holder.
- When proteins are displayed the diode “ PROT%” lights (fig.1, 3)
- When lactose is displayed the diode “ LACT %” lights (fig.1, 3)
- When water is displayed both diodes “ADD.WATER %” light. If the content
of water is below 3%, both diodes light permanently, but the indicator shows
the value 0,00%.
By pressing the PROGRAM button you may again show the Fat results.
Measured freezing point value is printed out.
5.3.2. Write down the results in the form. The results follow one after the
other till the sample-holder with a new sample of milk has been positioned in
the recess. If the analyzer was connected to a computer or a printer, it sends
the data to the computer or prints them.
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6. CLEANING THE ANALYZER
This procedure prevents gathering milk fat residues and milk stone on the
sensor. The milk stone consists of milk solids, calcium, iron, sulphates,
magnesium, etc. All these substances form layer on the pipe and sensor’s
walls, which leads to deviations in the measurement results and blocking up
the piping.
The company-producer recommends usage of the chemicals, supplied with
the analyser – alkaline and acidic (Lactodaily and Lactoweekly). You may
order them separately or together with the analyser. Try to use only these
chemicals for cleaning the analyser.
In case you missed to order these chemicals the alternative is to use alkaline
and acidic cleaning solutions for dairy, produced by one the companies,
supplying such chemicals:
http://www.johnsondiversey.com/Cultures/en-GB/OpCo/Your+Business/Dairies.htm
http://www.ecolab.com/SolutionGuide3.asp?name=1345&PS_GRP_CD=FDBV&BUS_NM
http://www.calvatis.com/documents/products/produkte_farm_melkhygiene.pdf
Do not use chemicals not intended for usage in the milking systems or
vessels in the dairy sector. Pay special attention to the concentration of the
acidic chemical. Increased concentration may damage the measuring
sensor.
6.1. Periodically cleaning (rinsing) the analyzer
It is done in the process of routine work of the analyzer. Its aim is to prevent
drying up and adhesion of different milk components in the milk analyzer’s
measuring system.
6.1.1. Periodical cleaning frequency.
It is easy to understand what is the period on which the rinsing could be done
as the analyzer reminds you when it is necessary. This is done by a sound
signal in 1-second cycle after the set time intervals elapse:
• 55 min. after switching on the power supply of the analyser, but idle
work;
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• 15 min. after the last measurement of real milk sample.
After cleaning completion, new measurement takes place in above described
time intervals.
The following message appears on the display:
Time to start
cleaning
6.1.2. Making the rinsing
After above message is received put in the recess of the analyzer a sample
holder with alkaline cleaning solution or water.
Press Enter to start the rinsing mode.
In this mode the analyzer makes 8 cycles and stops.
Already used solution is poured out of the analyser. Now the device is ready for
the next measurement. In case of doubt that the analyzer is still not well
cleaned, the procedure Cleaning may be executed repeatedly.
6.2. Complete cleaning
6.2.1. Complete cleaning frequency
This cleaning is done after finishing the work with the analyzer at the end of
the working day or if it is obvious that the measuring system of the analyzer is
contaminated in case of intensive work with it. It is done with alkaline cleaning
solution.
Preparation of 1 % alkaline solution of Lactodaily for circulation cleaning in
the milk analyzer:
1. Take the package 100 g concentrated powder chemical Lactodaily
2. Carefully cut the upper end, paying attention not to spill it.
3. In appropriate vessel (for example bucket) pour 1 l water.
4. Add the powder and then again water up to 10 l.
Then follow the instruction for milk analyzer cleaning.
6.2.2. Cleaning
6.2.2.1.Rinsing milk residues
Fill in the glass with water. Put it in the recess of the analyser and start
command Cleaning from the main menu. After finishing it pour out the
contaminated water.
6.2.2.2.Cleaning with alkaline cleaning solution
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Fill in the glass with warm (50-60 С) alkaline cleaning solution. Put it in the
recess of the analyser and start the command Cleaning from the main menu.
After finishing it, pour out the contaminated liquid.
6.2.2.3.Rinsing with water
Fill in the glass with water. Put it in the recess of the analyser and start
command Cleaning from the main menu. After finishing it pour out the
contaminated water. Now the device is ready for work.
6.2.2.4. Cleaning with acidic solution
It is recommended to be done at least 3 times weekly. The following procedure
is executed:
Rinsing the milk residues
Fill in the glass with water. Put it in the recess of the analyser and start
command Cleaning from the main menu. After finishing it pour out the
contaminated water.
Preparation of 1 % acidic solution of Lactoweekly for circulation cleaning in
the milk analyzer:
1. Take the package 100 g concentrated powder chemical Lactodaily
2. Carefully cut the upper end, paying attention not to spill it.
3. In appropriate vessel (for example bucket) pour 1 l water.
4. Add the powder and then again water up to 10 l.
Then follow the instruction for milk analyzer cleaning.
Fig. 5 Labels for the cleaning chemicals
6.2.2.5.Cleaning with acidic solution
Fill in the glass with warm (50-60 С) acidic cleaning solution. Put it in the recess
of the analyser and start the command Cleaning from the main menu. After
finishing it, pour out the contaminated liquid.
6.2.2.6. Rinsing with water
Fill in the glass with water. Put it in the recess of the analyser and start
command Cleaning from the main menu. After finishing it pour out the
contaminated water. Now the device is ready for work.
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IMPORTANT
THE MAIN REASON FOR MALFUNCTIONING OF THE
DEVICE IS THE BAD CLEANING OF THE SYSTEM AFTER
MAKING ANALYSIS.
In case of malfunction due to the bad cleaning of the
analyser your guarantee is not valid anymore and any
repair has to be paid.
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7.
POSSIBLE
MALFUNCTIONS
TROUBLESHOOTING
AND
ERROR
MESSAGES,
In the table below are described the possible malfunctions during the milk
analyzer’s exploitation. Also are described the ways of their repair / remedy. If
the problem persists after all recommended measures are taken, please,
connect the nearest service center.
Error
message
"Er.01"
or
"Er.03"
Accompanied
by
a
continuous
sound signal
"Er.02"
Operation Manual
Possible
problem /cause
Overheated milk
analyzer
Insufficient
quantity of the
milk
sample
sucked in the
system or air in
the sample
Repair/remedy
Immediately switch off the analyzer.
Pay attention the analyzer to be
situated away from direct sunlight or
heating devices.
Wait 5-10 minutes till the device to
cool down or to be normalized the
ambient temperature and switch it on
again.
The analyzer is ready to measure the
next sample. In order to avoid the
future appearance of the same error
message, please, check that:
- The sample is prepared according
the instructions and there aren’t
any air bubbles in it.
- There is a real suction of the
sample
after
starting
measurement, i.e. it is obvious
that the level of the milk sample in
the sample holder decreases. In
other case – there is damage in
the suction system.
- Avoid the end of the suction pipe
to be above the surface of the
liquid (not dipped enough).
- Avoid curdling of the milk sample.
Clean immediately if there is a
sample curdled in the system.
- Check the pipe, connecting
cleaning inputs on the analyzer’s
rear panel.
- In mode Measurement, after
starting the measurement, remove
the sample holder and see if there
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is no milk poured back in the
sample holder.
"Er.04"
Operation Manual
Sucked
overheated
sample
The analyzer is ready to measure the
next sample. In order to avoid the
future appearance of the same error
message, please, check that:
- The sample is prepared according
the
instructions
and
its
temperature does not exceed the
maximum permissible sample’s
temperature.
- Complete the procedure for
checking the analyzer in case of
error message Empty Camera.
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8. Test mode
8.1. Special (service) functions
Used for assigning different device parameters or starting the tests. To start
them switch on the power supply while pressing the Program button (fig. 1,
1). On the display the number of the function F.xx is changing in one-second
period. Release the button when the desired function is reached. This starts
its execution.
8.2. Function descriptions on their numbers:
1. Calibration. After choosing this function the indication CAL appears on the
display (fig. 1, 2). The device makes the measurement and sends the data
towards the calibration system via the technological network. It is used in the
production conditions when working with personal computer and program
LSC.EXE. Starting this function automatically directs the analyzer RS232
output towards a personal computer (on the analogy of function F.07 with
computer output).
2. Display test. Periodically are shown the numbers from 0000 to 9999, and
letters AAAA, bbbb, CCCC, dddd, EEEE, FFFF. LEDs (fig. 1, 3) are switched
on consequently one after the other in direction from the top to the bottom.
3. Pump test. Max. number of executed sample suction and release cycles is
9999. When it is reached the program stops.
4. Assigning the network number. The device is indicated in the calibrating
system under this number in case there is a connection with a personal
computer. Valid numbers are from 0 to 15 inclusive. When the function is
already selected (release of the Program button), the program stops, waiting
new pressing of the button. When it is pressed, the valid numbers are
displayed in one-second period, starting from currently stored. When needed
number appears on the display, release the button. This stores the number in
the device.
For correct work of the calibration system it is not allowed two or more
devices to have one and the same network number.
Assigning the network number is necessary in production conditions when
working with personal computer, program LSC.EXE or collecting data
computer network.
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5. Ultrasound test. Used in production conditions.
6. Device training – the sample is taken from the sample holder. Used in
production conditions. The results are sent to the computer via the
technological network.
Starting this function automatically directs the analyzer RS232 output towards
a personal computer (on the analogy of function F.07 with computer output).
7. Choosing the data format towards output RS 232. Two possibilities –
PC (personal computer) – measuring data collection program or Prn (serial
printer) – printing the measurement results.
Serial exchange parameters are: 9600 bps, No parity, 8 bits data, 1 stop
bit.
Starting functions F.01, F.06 automatically directs the analyzer RS232 output
towards a personal computer (on the analogy of function F.07 with computer
output). This means that after device test or calibration, in case of needed
printing out the measuring results, the output RS 232 has to be directed again
towards the serial printer.
8. Reserve.
9. Sample’s temperature correction. Allows increasing/decreasing the
temperature from +9.9 to –9.9 degrees centigrade. Consequence of work is
the same as it was already described in the correction functions for FAT,
COM etc. Used in production conditions.
From 10 to 27. Measured parameters corrections in every separate
calibration. Parameters are corrected independently one from the other for
each calibration. Possibility to display the correction, to set to zero, to
increase or decrease results with the steps pointed in the table below.
Consequence of work:
Release the Prog. button when the number of the needed function is reached
(see table with functions below), which starts the corresponding function.
Press again the button Prog. The display shows the current value correction.
Follows the measured value, which is possible to be increased with the
corresponding step. When the maximum positive correction is reached the
display shows values, with which the measured value can be decreased. This
procedure is cyclically executed. When the needed correction value is
reached, release the button to save the correction. Next pressing the button
passes to the next function.
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Correction functions table:
Function number
Fat
SNF
10
11
16
17
22
23
Den
12
18
24
Lac
13
19
25
Sol
14
20
26
Kas(Pro)
15
21
27
Calibration
N:
1
2
3
Below is the table with possible corrections, limits and changing steps:
Parameter
FAT
SNF
Density
Lactose
Solids
Proteins
Added water
Sample’s temperature
Increasement
0.95 %
4.75 %
4.75 %
0.95 %
0.95 %
0.95 %
9.00 %
9.90 oC
Decreasement
0.95 %
4.75 %
4.75 %
0.95 %
0.95 %
0.95 %
9.00 %
9.90 oC
Step
0.01 %
0.05 %
0.05 %
0.01 %
0.01 %
0.01 %
1.00 %
0.1 oC
Example:
Choose (prepare) two milk samples: the first one near the lowest limit of the
measuring range, the second one – near to the upper limit of the measuring
range.
Measure these samples, using the reference methods (Gerber or Rose Gotlib
for FAT, drying for SNF, Keldhal for Proteins).
And you receive:
First sample data from the reference methods: 2,3 FAT, 8,9 SNF, 3,3 Prot,
4,8 Lact.
Second sample data from the reference methods: 6 FAT, 8,5 SNF, 3,15 Prot,
4,7 Lact.
Make 5 time measurements of the same two samples with The milk analyser.
Leave the results from the first measurement and calculate the average value
of the rest 4 measurements for each parameter.
For example:
for the first sample measured with The milk analyser you’ve received the
following results: 2,45 FAT, 8,9 SNF, 3,4 Prot, 4,8 Lac;
for the second sample, measured with The milk analyser you’ve received the
following results: 6,15 FAT, 8,5 SNF, 3,25 Prot, 4,7 Lac.
It is obvious that the values for FAT and Protein differ from the reference
values with +0,15 FAT; +0,1 Prot.
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This means that you may correct the results by entering –0,15 for FAT using
above described method and -0,1 for Prot.
After the correction the device must show:
First sample: 2,3 FAT, 8,9 SNF, 3,3 Prot, 4,8 Lact
Second sample: 6 FAT, 8,5 SNF, 3,15 Prot, 4,7 Lact.
On the same way you may correct the rest of the parameters.
Second readings:
If you receive the following results from the first sample, measured with The
milk analyser: 2,1 FAT, 8,9 SNF, 3,4 Prot, 4,8 Lac;
second sample, measured with The milk analyser 6,2 FAT, 8,5 SNF, 3,25
Prot, 4,7 Lac.
It is obvious that the lower range is –0,2 , the upper +0,2. In this situation it is
not possible to use a correction, but the device needs a new calibration
according 8.2.3.4. Recalibrate using the same two milk samples.
When making corrections or calibrations you have to be 100% sure in the
correctness of the results from the reference methods of analyses.
From 28 to 30. Functions for measured water corrections for each
separate calibration. Possibility to display the correction, to set to zero, to
increase with 9% and decrease with –9% the result. The consequence of
work is corresponding to the above-described functions (10 to 27).
Water correction functions table:
Function number
Calibr. 1
Calibr. 2
Calibr. 3
r1.1 - Cow
r1.2 – Sheep r1.3 - UHT
28
29
30
Purpose
Water correction
New storage of the calibration coefficients values (recalibration) sets to zero
the previous values of the corresponding calibration.
31 to 33. Functions for increasing the basic freezing point absolute
value for each separate calibration. Serves for basic value editing. After
the function is chosen (releasing the Program button), the program stops,
waiting new pressing the button. After pressing it, in one-second period, the
increased absolute value is shown on the display, starting at currently saved
one. When the needed value is displayed, the operator has to release the
button, which saves the new value in the device.
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Functions table for increasing the absolute value of the basic freezing
point:
Function number
Calibration. 1 Calibration. 2 Calibration. 3
31
32
33
Purpose
Basic freezing point value
absolute value increasing:
34 to 36. Functions for decreasing the basic freezing point absolute
value for each separate calibration. Serves for basic value editing. After
the function is chosen (releasing the Program button), the program stops,
waiting new pressing the button. After pressing it, in one-second period,
the decreased absolute value is shown on the display, starting at currently
saved one. When the needed value is displayed, the operator has to release
the button, which saves the new value in the device.
Functions table for decreasing the absolute value of the basic freezing
point:
Function number
Calibration. 1 Calibration. 2 Calibration. 3
34
35
36
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Purpose
Basic freezing point value
absolute value decreasing:
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Test table
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
Operation Manual
Function
Calibration/CAL/
Test display
Pump test
Assigning network number
Ultrasound test
Device preparation /CICL/
Choosing the data format towards output RS 232
Reserve
Temperature correction
Fat Correction, calibration N:1
SNF Correction, calibration N:1
Den Correction, calibration N:1
Lac Correction, calibration N:1
Sol Correction, calibration N:1
Kas(Pro)Correction, calibration N:1
Fat Correction, calibration N:2
SNF Correction, calibration N:2
Den Correction, calibration N:2
Lac Correction, calibration N:2
Sol Correction, calibration а N:2
Kas(Pro)Correction, calibration N:2
Fat Correction, calibration N:3
SNF Correction, calibration N:3
Den Correction, calibration N:3
Lac Correction, calibration N:3
Sol Correction, calibration N:3
Kas(Pro)Correction, calibration N:3
Water Correction, calibration N:1
Water Correction, calibration N:2
Water Correction, calibration N:3
Increasing the basic freezing point, calibration N:1
Increasing the basic freezing point, calibration N:2
Increasing the basic freezing point, calibration N:3
Decreasing the basic freezing point, calibration N:1
Decreasing the basic freezing point, calibration N:2
Decreasing the basic freezing point, calibration N:3
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APPENDICES
APPENDIX 1 METHODS
1. Determination of milk's density
1.1. General
Milk density is defined as relation between the mass of definite milk volume at
temperature 20 oС and the mass of equal volume distilled water at
temperature 4 oС.
Density, alone, could not be used as a control parameter at milk quality
control. Using the density the tentative figures for the SNF and solids could
be determined.
1.2. Sampling and preparation for analyses
Sampling milk or other milk derivatives and their preparation for analyses is
done according corresponding Appendices.
Milk density is determined not earlier than 2 h after milking. The milk must be
with temperature from 10 to 25 oС.
Before determination of density the milk must be well stirred. To avoid foam
formation, it has to be carefully poured on the cylinder’s walls. The cylinder
must be slightly tilted.
Before taking the readings the cylinder, with the milk must be placed on an
even surface, facing the light, so the readings could be easily seen.
1.3. Basic principles.
The density of the milk is determined using aerometer, also called lactodensity-meter (milk density meter) and is expressed with a number,
representing milk density meter degrees, decreased 1000 times or only with
milk density meter degrees.
1.4. Necessary devices and reagents
- Aerometer /lacto-density-meter, milk meter/.
- Cylinder – with inner diameter not less than 5 сm, and length, corresponding
to the dimensions of the lacto-density-meter.
- Ammonium with preliminary defined relative density.
1.5. Making the determination:
Dry and clean, the lacto-density-meter is slowly dipped in the milk till division
1,030, and then is left in free-floating state. The lacto-density-meter must not
touch the cylinder’s walls and to be on at least 5 mm from them.
When taking the readings the eyes must be on one and the same level with
the meniscus. The reading is done in the meniscus’ upper end with accuracy
till 0,0005, and the temperature – with accuracy till 0,5 oС.
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The difference between two parallel determinations must be not more than
0,0005.
1.6. Recalculating the values according lacto-density-meter at 20 oС.
If the milk, when determining its density, has temperature, higher or lower
than 20 oС, the readings from lacto-density-meter are recalculated towards 20
o
С.
Density recalculation towards 20 ОС is done on the following way:
for every temperature degree over 20 ОС from the received by the milkmeter
value are added 0,2 o for the cow and goat milk and 0,25 o for sheep and
buffalo milk lacto-density-meter degreed or 0,0002, respectively 0,00025
towards density; and for every temperature degree under 20 oС from the
readings of milkmeter value are deducted 0,2-0,25 lacto-density-meter
degrees or 0,0002, (0,00025) from the density.
2. Determination of fat content in the milk and milk derivatives.
2.1. General
For making analyses are used pure reagents for analyses (pure reagents for
analyses (p.r.a.) and distilled water or water with equivalent purity.
2.2. Sampling
Milk and milk derivatives sampling is done according Appendices Milk
sampling and preparation of samples for analyses ad Sampling and
preparation of samples for verification the accuracy of the milk analyser,
making corrections and recalibration.
2.3. Basic principles.
The method uses dissolving the milk and dairy products proteins with
sulphuric acid with definite concentration in butyrometer and separating the
fat under the influence of amilic alcohol, heating and centrifuging in a form of
dense transparent layer, the volume of which is measured in the graduated
part of the butyrometer.
•
•
•
•
•
2.4. Necessary devices and reagents
Butyrometers for milk, special for skimmed milk and cream;
Rubber stopples for butyrometers;
Stand for butyrometers;
Special pipettes or automatic for milk, sulphuric acid and изоамилов
alcohol from 1, 10 and 11 сm3;
Pipettes from 1 and 20 сm3;
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Glasses from 25 till 50 сm3;
Centrifuge for Gerber;
Water bath;
Mercury thermometers up to 100 oС with value scale 1 oС;
Sulphuric acid with density 1,82 at 20 oС for determination of fat content
of the milk;
• Isoamilic alcohol for Gerber with density 0,811 to 0,812.
•
•
•
•
•
2.5. Making the determination:
Preparation of samples for analyses.
The milk is mixed well in order to become homogenous mixture (if necessary
it is slowly heated up to 35-40 оС ) and is carefully shaken and tempered to
20±2 оС. The samples from whey and buttermilk are preliminary filtered
through double layer gauze and is then tempered to 20±2 оС. Cream samples
are placed in water-bath at temperature 35 till 40 оС, stirred till homogenous
sample is received and cooled down to 20±2 оС.
2.6. Making measurement
With butyrometer for milk
For milk, whey and buttermilk.
With automatic or special for acids pipette are measured 10 сm3 sulphuric
acid with d=1,820 кg/m3 at 20 оС in the milk butyrometer. Carefully on the
butyrometer's walls are piled up 11 сm3 from the prepared sample. The
pipette is held till its full drainage.
For cream
From the prepared sample is measured 10 g with error up to 0,001 g and 50
сm3 water are added. Mixture is well stirred and heated up to 30-35 оС, then
is again stirred and cooled down to 20±2оС, and the following steps are as
with the milk sample using sulphuric acid with d=1,789 till 1,790 кg/m3.
With butyrometer for cream
For cream
5 g from the sample are measured with butyrometer with error up to 0,0001 g
and then 5 сm3 water are added, 10 сm3 sulphuric acid with d=1,780 to 1,790
кg/m3 at 20 оС and 1 сm3 изоамилов alcohol. The butyrometer is closed with
rubber stapple and is shaken till the proteins are fully dissolved.
2.7. Calculating the results
By using milk butyrometer
Milk, whey, buttermilk.
Using the butyrometer's graded scale the grams fat in 100 g product are read
directly. When the milk is curdled, the result is increased with 0,1 g for every
degree.
By using cream butyrometer.
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Cream
Using the butyrometer's graded scale the fat content in the products is
directly read in percentages.
2.8. Measurement accuracy
By using milk butyrometer
The difference between two parallel determinations could not exceed:
For skimmed milk, whey and buttermilk - 0,05 g for 100 g product;
For cream - 0,5 g for 100 g product;
For milk - 0,1 g for 100 g product;
By using cream butyrometer
The difference between two parallel determinations could not exceed 0,5 g
for 100 g cream.
3. Determination of water content and solids in the milk and milk
derivatives.
3.1. General
The solids represent the fat content, proteins, carbohydrates and salts.
Sampling is done according Appendices Milk sampling and preparation of
samples for analyses ad Sampling and preparation of samples for verification
the accuracy of the milk analyser, making corrections and recalibration.
3.2. Basic principles.
Water content is determined by weight when drying at temperature (102±2)
о
С of the weighted product till constant mass, expressed in grams for 100 g
product.
The solids/dry substance is the mass of the dry remainder, received after
dehydration of determined quantity product at temperature (102±2) оС till
constant mass and is expressed in grams for 100 grams of the product.
3.3. Necessary devices and reagents
- Assay balance with loading bounds 200 g and error 0,0002 g.
- Mercury thermometers from 0 to 100 ОС and from 0 to 150 oС with value of
scale division 1 oС;
- Pipettes from 5 to 10 сm3, class II;
- Glass banks with grind stopples with volume 100-200 сm3;
- Drying-oven with thermal regulator for keeping the temperature (102±2) oС;
- Exicator with silicagel or another hygroscope material;
- Weight plates;
- Peg for the weight plates;
- Glass pods with rounded ends;
- Quartz, sea or river sands.
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3.4. Making the determination:
Sample preparation for analyses.
The milk (whey, cream, and buttermilk) is well shaken. If needed, the sample
is heated slowly up to 38-40оС, it is well mixed and cooled down to 20оС.
Mixing and pouring are done at least three times in dry and clean vessel.
3.5. Making the measurement
The weight plate with 20-30 g washed out and tempered sand and glass rod
is dried at 102±2 оС for 1 h, and then is taken out, covered with the cap,
tempered with exicator (up to 30 min) and the mass is weighted with
accuracy up to 0,0005 g. In the weight plate, using pipette, at about 10 сm3
milk are poured, covered and weighted. With the help of the glass rod milk is
well mixed with the sand and without a cap is heated on a water-bath till a
homogenous mass is formed. Then the weight plate is put in a drying-oven at
temperature 102±2оС, it is dried out for 3 h, it is taken out of the oven,
covered with the cap, tempered in exicator (up to 30 min) and the mass is
weighted. Weight-glass is placed in the drying-oven again and is dried 1 h,
then is taken out, tempered and weighted. This procedure is repeated till the
difference between two consequent measurements becomes not more than
0,004g. In case that at the second or following drying procedure mass
increases, then for the calculation is taken the previous measurement.
3.6. Calculating the results
Water content in grams for 100 g product (milk or milk derivatives), is
calculated by the formula:
X =
M2 − M3
∗ 100
M 2 − M1
Where
М1 - the mass of the plate with the sand and the glass rod, g;
М2 - the mass of the plate with the sand, the glass rod, and the sample
before drying, g;
М3 - the mass of the plate with the sand, the glass rod, and the sample after
drying, g;
The dry substance (Y) is calculated using the formula:
Y= 100 - Х,
Where:
Х is the calculated water content.
3.7. Measurement accuracy.
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The difference between tow consecutive measurements of one and the same
sample could not be more than 0,2 g for 100 g product.
4. Determination of casein content in the milk.
4.1. General
The methods are based on the Volker's method.
For making the analyses are used pure reactive for analyses (p.r.а.) and
distilled water or water with equal purity.
4.2. Sampling
According corresponding Appendices.
4.3. Basic principles.
Added to the milk formalin liberates acidic residuum from the protein's end
groups, which are titrated with soda caustic solution. The soda caustic
quantity is proportional to the casein in the milk content.
4.4. Necessary devices and reagents
- Glass 250 сm3.
- Pipettes Foll - 25,5 сm3.
- Pipettes Mor from 1 сm3, with division 0,1 сm3.
- Soda caustic p.r.а. - 0,143 n solution.
- Formalin 40% p.r.a - freshly neutralized.
- Phenolphthalein - 2 % solution in 70 % ethyl alcohol.
- Potassium oxalate p.r.а. 28 % water solution.
- Cobalt sulphate p.r.а. 5 % water solution.
4.5. Making the determination:
For cow milk
Reference sample preparation.
20 cm3 from the measured milk are poured in a glass vessel together with 1
cm3 3 % water solution of cobalt sulphate. The sample is shaken and a slight
rose color of the solution is received, which serves as a standard in the
research.
4.6. Making the measurement
20 cm3 from the milk are measured in a glass and a titrated with 0,1 N soda
caustic, using phenolphthalein as an indicator, till the color of the standard
sample is reached. The volume of the used soda caustic is not taking into
consideration.
4 cm3 38-40 % formalin are added towards the neutralized sample and the
rose color disappears as a result of the liberated carboxylic groups. It is well
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stirred and titrated with 0,1 N soda caustic, till slight rose color is recovered.
At the second titration the volume of the used soda caustic is measured.
For sheep milk
Casein content in sheep milk is determined on the same way. The only
difference is that instead of 4 cm3 38-40 % formalin in the milk are added 6
cm3, and the standard/reference sample is prepared with 1 cm3 4 % solution
of cobalt sulphate.
4.7. Calculations
The quantity of the 0,1 N soda caustic in cm3, used in the second titration,
multiplied by the coefficient 0,7335 is equal to the casein content in the milk
in percentages.
The following tables could be used for quicker readings of casein's
percentage on the base of used cm3 0,1 N soda caustic:
Table I
Calculation of casein content in the cow milk on the base of used cubic
centimeters 0,1 N soda caustic:
0,1 n NaOH
cm3
3,00
3,05
3,10
3,15
3,20
3,25
3,30
Operation Manual
Casein
%
2,20
2,24
2,27
2,31
2,35
2,38
2,42
0,1 n NaOH
cm3
3,35
3,40
3,45
3,50
3,55
3,60
3,65
Casein %
19.04.08
2,46
2,49
2,53
2,56
2,6
2,64
2,68
0,1 n NaOH
cm3
3,70
3,75
3,80
3,85
3,90
3,95
4,00
Casein
%
2,71
2,75
2,79
2,82
2,86
2,90
2,93
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Table II
Calculation of casein content in the sheep milk on the base of used cubic
centimeters 0,1 N soda caustic:
0,1 n NaOH
cm3
5,40
5,45
5,50
5,55
5,60
5,65
5,70
5,75
5,80
5,85
5,90
5,95
6,00
6,05
Casein
%
3,96
4,00
4,03
4,07
4,10
4,14
4,18
4,22
4,25
4,29
4,33
4,36
4,40
4,44
0,1 n NaOH
cm3
6,10
6,15
6,20
6,25
6,30
6,35
6,40
6,45
6,50
6,55
6,60
6,65
6,70
6,75
Casein %
4,47
4,51
4,55
4,58
4,62
4,66
4,69
4,73
4,77
4,80
4,84
4,88
4,91
4,95
0,1 n NaOH
cm3
6,80
6,85
6,90
6,96
7,00
7,05
7,10
7,15
7,20
7,25
7,30
7,35
7,40
7,45
Casein
%
4,99
5,02
5,06
5,10
5,13
5,17
5,21
5,24
5,28
5,32
5,35
5,39
5,43
5,46
4.8. Measurement accuracy.
Two parallel samples are measured and the difference between them could
not exceed 0,1 %.
The accuracy of the method require the work to be done at place with good
natural illumination, titration to be done evenly, without interruptions, colorless
formalin to be used, preliminarily neutralized with soda caustic and
phenolphthalein indicator.
Formalin titration is easy method, but it is not enough precise. More accurate
results for casein content are obtained using Kjeldhal's method, but it requires
special appliances.
5. Determination of salts in the milk
5.1. General
For the mineral substances in the milk conclusions can me made on the
ashes content.
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5.2. Sampling
According Appendices Milk sampling and preparation of samples for analyses
ad Sampling and preparation of samples for verification the accuracy of the
milk analyser, making corrections and recalibration.
5.3. Basic principles.
Milk is dried, carbonized and turned to ashes till constant mass. The ashes
received are calculated in percentages.
•
•
•
•
•
•
•
•
5.4. Necessary devices and reagents
Assay balance;
Crucibles;
Water-bath or infrared lamp;
Hot plate or burner;
Drying-oven with thermal regulator;
Muffle furnace;
Exicator;
Quantity filter.
5.5. Making the determination:
In preliminary tempered and weighted crucible of the assay balance at about
10 g milk is weighted with accuracy up to 0,0005 g. The crucible with the
sample is placed in a water-bath or infrared lamp till the evaporation of milk to
dry state. Then it is carbonized with the burner or on a hot plate, paying
attention not to be splashed out. The crucible is placed in a muffle oven and
turns to ashes slowly, without the sample to be kindled, at temperature 500550 оС till white or grey-white ashes. It is tempered in an exicator and is
weighted till the appointed accuracy. Heating up in the oven is repeated till a
constant mass is received.
5.6. Calculations
Ashes content is calculated using the formula
ashes =
(C − A)
∗ 100
( B − A)
Where:
А – the mass of empty, tempered crucible, g
В – the mass of the crucible together with the milk, g
С – the mass of the crucible with the received ashes, g
5.7. Measurement accuracy
The difference between tow parallel determinations could not be more than
0,02 %.
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APPENDIX 2 REPRESENTATIVE SAMPLES FROM MILK AND OTHER
MILK DERIVATIVES FOR MILK ANALYSER’S CALIBRATION
1. General
The samples used for analyser’s calibration have to be representative for the
corresponding milk type and have to be with known quality parameters: fat in
percentage, SNF in percentage, density, lactose in percentage, total protein
in percentage and salts in percentage. Changes in the analyzed parameters
in the samples have, if possible, to cover the whole measuring range – i.e.
used samples to be with low, middle and high content of the analyzed
components.
The exact value of the parameters is decisive for correct and accurate
calibration, because if the parameters are not set correctly during calibration
the same parameter will not be measured correctly.
2. Necessary quality parameters values determination
For more precise determination of above listed quality parameters of the milk
and its derivatives is advisable they to be examined in an authorized
laboratories, using the corresponding arbitration methods for this purpose.
2.1. Laboratory methods
2.1.1. Determination of fat content
Determination of fat content in the milk and its derivatives (cream, whey,
buttered milk) is one of the most important analyses in the dairy production
and milk processing. According this parameter the payment schemes are
made and it is observed from the point of view correct production process
and the basic economy balances are made with its help.
А/ Röse-Gottlieb method
The fat content is determined using the gravimetric method, fat extraction
from ammonia-alcohol milk solution using diethyl and petroleum ether,
evaporation of the solvent and weighting the residuum.
B/ Gerber method
The proteins in the milk and dairy products are dissolved with sulphuric acid
with definite concentration in butyrometer and the fat is separated under the
influence of amyl alcohol, heating and centrifuging in a form of dense,
transparent layer. The volume of this layer is measured in the divided part of
the butyrometer.
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This is quick, easy method with sufficient accuracy. We recommend it for
usage. For more detailed description see Appendix Methods.
2.1.2. Milk density determination
А/ With picnometer and Mor-Vestval scales
This is the most exact method for determination of milk and its derivatives’
density.
B/ with aerometer (lacto-density-meter)
Compared with the above method this is quick and easy readable with
satisfactory accuracy. We recommend it. For more detailed description see
Appendix Methods.
During the lactation period and under the influence of different zoo
engineering factors the density of the different milk kinds varies in the
following bounds:
Milk kind
Cow
Buffalo
Goat
Sheep
Minimum
1,027
1,026
1,027
1,031
Maximum
1,033
1,032
1,033
1,040
Average
1,030
1,029
1,030
1,034
2.1.3. Determination of total proteins
А/ Kjeldahl method
Heating with concentrated sulphuric acid in the presence of catalyst
mineralizes a definite volume of the milk sample. The liberated ammonium
combines with the sulphuric acid and forms ammonium sulphate. After adding
surplus soda caustic ammonium is liberated. When distilled it combines with
the boronic acid. The quantity of the combined ammonium is determined by
titration with acid with determined titer. From the combined with the
ammonium acid the initial nitrogen content is determined, and also the
proteins in the milk.
B/ Titration with formalin
Formalin, added to the milk, combines with the amino group in the protein’s
molecule and forms methyl groups, which have no alkaline reaction. Milk
acidity increases by the liberated carboxylic groups, which are titrated with
soda caustic solution. The used volume soda caustic is proportional to the
protein content in the milk.
2.1.4. Determination of casein content in the milk
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А/ Kjeldahl method
The total nitrogen content in the milk is determined. Casein is precipitated
with acetic acid (acetate buffer) and is filtrated. The content of nitrogen in the
filtrate is determined. Casein content is the difference between the two results
for nitrogen using the Kjeldahl’s method.
B/ Titration with formalin
More details for this method – see Appendix Methods.
2.1.5. Determination of salts in milk.
For the salts in milk and its derivatives is judged by its ashes content. Milk
dries, becomes carbonized and turns to ashes till constant mass. The ashes
received are calculated in percentage.
2.1.6. Determination of solids in milk
Solids describe the content of fats, proteins, carbohydrates and salts. Its
value may be used for determination of each of these parameters in case of
known other values.
Salts are determined by drying till constant mass – see Appendix Methods.
Express methods by using another milk analysers
It is possible another device to be used for determination of some of the
quality parameters of milk and its derivatives samples, intended for
calibration, but it has to be noted that it is possible incorrect values to be
received, that’s why it is necessary to be completely sure in the accuracy of
their readings.
Usage of Milkoscan and other milk analysers based on the infrared
measurement principle.
By using it the fat, lactose and protein content may be determined. Problem
may arise with determination of salts and SNF. This is due to the impossibility
of the infrared method to determine the solids and in order to receive the
solids in the sample their meaning is accepted as a constant.
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APPENDIX 3 MILK SAMPLING AND PREPARATION OF SAMPLES FOR
ANALYSES
1. General
Milk sampling and qualification of raw, thermally treated milk and its
derivatives (cream, whey, buttermilk etc.) is accomplished for every separate
homogeneous batch. As homogeneous batch is accepted:
• Milk, delivered by a separate producer (an individual farm, farm etc.),
and received from one kind of animals after their complete milking,
independently from the number of milk-cans and tanks.
• Milk, received from one or several farms or milk collecting centers, but
delivered in a joint vessel.
• In the enterprise – from one and the same kind raw milk poured in one
vessel.
• For cream, whey, buttermilk etc. – produced as a result of milk
processing and its derivatives from one and the same kind and quality,
poured in a separate vessel.
Milk is qualified not earlier than 2 hours after milking.
When the milk is frozen it has to be warmed up to 10-15 oС and stirred
according the below-described procedure.
A sample is taken from every separate vessel proportionally to the quantity of
the milk in it. Samples from the different vessels are mixed well and from the
received medial sample are taken 200 - 250 cm3 for accomplishing the
needed analyses.
2. Stirring the milk and its derivatives before sampling
Milk stirring
It is a very important condition for receiving exact results. Before taking
samples from big vessels the milk (fresh or thermally treated, whole-milk or
whipped) has to be well stirred for no less than 5 min., by vertical and circular
slow movements. Mixing spoon with long handle is used, allowing the lowest
layers of the liquid to be reached.
The milk in the milk-cans is stirred 5 to 8 times from the surface to the bottom
and reverse with slow circular movements.
Cream stirring
Due to the fact that the cream is significantly thicker liquid than the milk and
contains high percentage fat it has to be preliminary very well stirred from the
surface to the bottom with reciprocation movements at about 20-25 times.
Whey and buttermilk stirring
It is analogical to milk stirring.
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3. Sampling
Samples from milk, whey or buttermilk are taken with metal or glass pipe (dry,
clean and stainless-steel) with diameter at about 10 mm, which is slowly
dipped till the bottom of the vessel and its upper end remains open. In this
way it is filled with milk simultaneously with its dipping. When the pipe is
taken out of the vessel its upper end has to be tightly closed with a thumb.
For a bigger reliability of the analyses results it is recommended the quantity
of the taken sample to be no less than 200 ml.
Cream sample is carefully well stirred in order not to form foam. For taking a
medial sample from milk-cans and tanks a sample pipe is used. Stuck to its
outer surface cream has to be removed by using filter paper, napkin or clean
cloth, preventing in this way the proportionality between the samples and the
total amount of the cream to be disturbed.
4. Sample preservation
The vessels where the samples will be put have to be clean, dry, glass, metal
or from other suitable material, to be tightly closed with rubber or other
stopples. The stopples not to absorb water and fat and not to influence the
analyses sample content.
In summer the sample fills up to the top the vessel, but in winter – at least 3/4
from the vessel’s volume. Each sample for analyses has to be labeled and
described in a way not allowing to be mixed up.
The samples are stored in conditions, assuring temperature, corresponding to
the requirements for storing such kind of product (advisable – 1 oС).
If there is a need of longer sample storing they have to be preserved; the
most commonly used preservative is potassium dichromate (K2Cr2O7) - 1 g
for 1 000 ml. The samples have to be stored in a cold and dark place after the
preservation. Have in mind that during the analyses the results for SNF% will
be increased with 0,1 %. After adding the preservative the sample has to be
well stirred.
Do not make analyses if the acidity of the milk is more than 25oT for cow and
28 oT for sheep milk.
5. Preparing the samples for analyses
Milk – raw and thermally treated
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When examining samples taken immediately before analyses and shortly
stored, the milk is poured several times from vessel to vessel in order to
distribute the fat content uniformly. To avoid foam formation or separation of
milk fat, the samples have to be carefully poured using the walls of the
vessels, as they are tilted slightly. For a better mixing the sample it has to be
poured at least 3 times. When needed the same is tempered to the
temperature within the measuring range.
If there is fat stuck on the walls of the vessel and the stopple (when the
samples were stored for a long time), the milk has to be slowly heated up to
35-40 oC. At the same time it has to be slowly shaken. The cream, stuck to
the walls of the vessel is removed. The sample is poured several times and is
cooled down (advisable up to 20 oС).
If there is separated liquefied fat or white particles with irregular form on the
vessel’s walls reliable results could not be received.
Whey
Before making analyses the whey sample is filtered through double sheet
gauze put over the glass funnel in order to separate the fat grains get into
liquid by incidence and if it is needed the sample is tempered and carefully
stirred.
Buttermilk
Before making analyses the buttermilk sample is filtered through single sheet
gauze put over the glass funnel in order to separate the big protein particles
and if it is needed the sample is tempered and carefully stirred.
Cream
The sample is slowly warm up to 35 – 40 oС in water bath. The fat is
dispersed wholly by carefully shaking and if necessary, by stirring with glass
stick. The sample is poured from vessel to vessel several times and is cooled
down (advisable to 20 oС). If after this procedure the sample is not
homogenous, the measurement is not carried out.
Sample for analyses is prepared from homogenized cream by diluting it with
distilled water in degree, sufficient for the components of the diluted cream to
be reached in the measuring range of the analyser.
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APPENDIX 4 SAMPLING AND PREPARATION OF SAMPLES FOR
VERIFICATION THE ACCURACY OF THE MILK ANALYSER, MAKING
CORRECTIONS AND RECALIBRATION.
1. Necessary consumables and devices
• Distilled water;
• Minimum 3 milk samples with known content of fat, SNF, protein,
density, lactose, solids;
• Heating water bath;
• Cooling water bath or chamber;
2. General
Milk sampling and storage of samples of raw, thermally treated milk and its
derivatives (cream, whey, butter-milk etc.) aiming verification the accuracy of
the analyser, making corrections and recalibration is accomplished following
the recommendations below:
• Sample to be taken from homogeneous batches, observing all the
requirement;
• The sample’s volume to be enough for making minimum 5
measurements for each sample or not less than 0.5 l;
• The samples to correspond to the standard physic-chemical and
microbiological requirements, to be pure, without admixtures, without
added cleaning or other unusual substances and without falsifications;
• Do not use samples with total acidity of milk more than 17oT;
• Vessels, where the samples will be handled have to be clean, dry,
glass, metal or other suitable material, to be tightly closed with rubber
or other stopples. The stopples not to absorb water and fat and not to
influence the analyzed sample content;
• Till the start of the analyses the samples are stored in conditions,
assuring preservation of their content and quantities (advisable low
temperature – 1-3 oС).
For longer storage of the samples a preservative is added as was already
described in p.9.1.1, and then the sample has to be well stirred.
3. Representative Samples
The samples have to be representative for the corresponding milk type.
Changes in the analyzed parameters in the samples have, if possible, to
cover the whole measuring range – i.e. used samples to be with low, middle
and high content of the analyzed components.
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Exemplary recommended values:
Cow milk
Parameter
% fat content
% Solids-Non-Fat content
Low value
2,00
8,00
High value
6,00
9,00
The Lactose percentage content (4,0-5,5; average-4, 7), Protein (2,00-4,00;
average-3, 3), salts (0,7-0,8) is proportional to the SNF content. When
preparing samples these values vary within limited bounds.
Sheep milk
Parameter
% fat content
% Solids-Non-Fat content
Low value
5,50
9,00
High value
10,00
11,50
The Lactose percentage content (average - 4,6), Protein (average - 5,8), salts
(average - 1,0) is proportional to the SNF content. When preparing samples
these values vary within limited bounds.
Buffalo milk
Parameter
% fat content
% Solids-Non-Fat content
Low value
5,50
9,00
High value
10,50
11,00
The Lactose percentage content (average - 4,7), Protein (average - 4,3), salts
(average - 0,8) is proportional to the SNF content. When preparing samples
these values vary within limited bounds.
Goat milk
Parameter
% fat content
% Solids-Non-Fat content
Low value
2,00
8,00
High value
6,00
9,00
The Lactose percentage content (average - 4,6), Protein (average - 3,7), salts
(average - 0,8) is proportional to the SNF content. When preparing samples
these values vary within limited bounds.
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Cream
Parameter
% fat content
% Solids-Non-Fat content
Low value
8,00
2,50
High value
20,00
5,00
The cream samples are diluted with distilled water. Degree of dilution is 2-3
times, in dependence of the initial fat content in the cream.
Whey
Parameter
% fat content
% Solids-Non-Fat content
Low value
0,20
5,00
High value
0,80
7,50
The content of fat and SNF in the whey depends on the kind of the dairy
product as a result of which the whey is received.
4. Samples preparation
Milk – raw or thermally treated
For raw milk sample with average content of the analyzed components is
advisable to be used milk, collected from at least 10 animals from the most
commonly met breed in the region where the analyser will be functioning.
Low fat and high fat samples are prepared on the following way:
Available fresh or thermally treated milk is poured in a separating funnel,
which is place in a refrigerator for at least 12 hours at temperature 4 - 6 °С in
order to stratify. For a bigger stratification a longer time is required.
The layer at the bottom is poured in a vessel. It is well mixed by pouring it
from vessel to vessel and is warmed up to 40 °С in a water bath.
The upper layer is poured in another vessel.
Using the certified methods the density and the concentration of the analyzed
components - fat, protein, SNF, lactose, salts are determined.
The analyser’s accuracy depends only on the correctness of the chemical
analyses of the components in the samples and the normal acidity during
calibration!
It is recommended the first cow milk sample with low fat content to be with the
following parameters:
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1.8-2% FAT; 8.7-9% SNF; 3,3-3,5 % Protein; 4,8-4,9% Lactose; 0,75 Solids;
1030-1033 kg/m3 Density.
The second cow milk sample with high fat content to be with the following
parameters:
5-5,5% FAT; 8.4-8,79% SNF; 3,1-3,2% Protein; 4,6-4,7% Lactose; 0,7 Solids;
1028-1029 kg/m3 Density.
Samples with medial values of the separate parameters are received by
mixing the two boundary values in a definite proportion.
Preserve the samples, using above described method for their longer
storage.
When using samples, stored shortly, preliminary pour the sample from one
vessel to another in order to distribute the milk components evenly paying
attention not to form foam in the sample.
When the samples are stored for a longer period it is recommended to warm
it up to 35-45 °С, and the vessel to be shaken carefully. In case that there is a
cream stuck on the vessel’s surfaces – remove it. The sample is poured from
vessel to vessel several times and is cooled down (advisable to 20 °С /.
If there is separated liquefied fat or white particles with irregular form on the
vessel’s walls this sample could not be used.
Whey and buttermilk
The samples are poured several times from vessel to vessel and if needed
gradual heating with stirring with cooling down is done.
Cream
The sample is slowly warmed up to 35 – 40 °С in water bath. The fat is
dispersed wholly by carefully shaking and if necessary, by stirring and
pouring it from vessel to vessel till its full homogenization.
From homogenized cream is prepared sample for analyses by diluting it with
distilled water in degree, sufficient for the components of the diluted cream to
be reached in the measuring range of the analyser.
5. Advisable scheme for independently determination the content of
different parameters in milk and its derivatives
When is not possible to use the help of authorized laboratories and above
mentioned milk analysers we recommend you to follow the scheme:
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5.1. For cow milk (whole milk, low fat, skimmed milk) and UHT milk
Determination of fat content – Gerber’s method, described in Appendix
Methods.
Density determination – using aerometer, described in Appendix Methods.
SNF determination – by formula – p. 3.2.3.1.B
Determination of Lactose content – by formula – p.3.2.3.2.А
Determination of salts content – by formula – p. 3.2.3.3.А
Total protein content determination – by formula – p. 3.2.3.4.А
Example: Determination of the quality parameters for two samples cow milk
(low fat and high fat), obtained and prepared according p. 2.3.1 and 2.4.1.
First – determine the fat content in the samples, using the Gerber’s method
(p.3.2.)
Suppose that for the first sample the result is 2,0 %F, for the second – 5,9
%F.
Second – determine the milk density, using aerometer (p.3.1.)
Suppose that the results are 1,0316 for the first sample and 1,0274
for the second
Third – Calculate the SNF content using the formula (p.3.2.3.1.B)
SNF =
0,075 ∗ 2,0 + 100 − 100 / 1,0316
= 8,50%
0,378
SNF =
0,075 ∗ 5,9 + 100 − 100 / 1,0274
= 8,23%
0,378
Fourth – determine the lactose content by the formula (p.3.2.3.2.А)
Lact. = SNF * 0,55 = 8.50 * 0.55 = 4.67 %
Lact. = SNF * 0,55 = 8.23 * 0.55 = 4.53 %
Fifth – determine the solids content by formula (p.3.2.3.3.А /
Salts = SNF * 0,083 = 8.50 * 0.083 = 0.71 %
Salts = SNF * 0,083 = 8.23 * 0.083 = 0.68 %
Sixth – determine the total protein content by formula (p.3.2.3.4.А)
Proteins = SNF * 0,367 = 8.50 * 0.367 = 3.12 %
Proteins = SNF * 0,367 = 8.23 * 0.367 = 3.02 %
So, when calibrating the milk analyser we’ll use samples with the following
parameters:
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milk fat
SNF
density
lactose
salts
proteins
I Ist sample
(low fat)
II nd sample
(high fat)
2,00
8,50
1,0316
4,67
0,71
3,12
5,90
8,23
1,0274
4,53
0,68
3,02
5.2. For sheep milk
Determination of fat content – Gerber’s method, described in Methods p. 3.4.
Density determination – using aerometer, described in Methods p. 3.3.
SNF determination – by formula – p. 3.2.3.1.B
Determination of Lactose content – by formula – p. 3.2.3.2.А
Determination of solids/salts content – by formula – p. 3.2.3.3.А
Total protein content determination – by formula – p. 3.2.3.4.А
Example: Determination of the quality parameters for two samples sheep
milk (low fat and high fat), obtained and prepared according p. 2.3.1 and
2.4.1.
First – determine the fat content in the samples, using the Gerber’s method
(p.3.2.)
Suppose that for the first sample the result is 5,6 %М, for the second – 9,8
%М.
Second – determine the milk density, using aerometer (p.3.1.)
Suppose that the results are 1,0352 for the first sample and 1,0300
for the second
Third – Calculate the SNF content using the formula (p.3.2.3.1.B)
SNF =
0,075 ∗ 5,6 + 100 − 100 / 1,0352
= 10,11%
0,378
SNF =
0,075 ∗ 9,8 + 100 − 100 / 1,0300
= 9,65%
0,378
Fourth – determine the lactose content by the formula (p.3.2.3.2.А)
Lact. = SNF * 0,45 = 10.11 * 0.45 = 4.55 %
Lact. = SNF * 0,45 = 9.65 * 0.45 = 4.34 %
Fifth – determine the solids content by formula (p.3.2.3.3.А /
Solids = SNF * 0,075 = 10.11 * 0.075 = 0.76 %
Solids. = SNF * 0,075 = 9.65 * 0.075 = 0.72 %
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Sixth – determine the total protein content by formula (p.3.2.3.4.А)
Proteins = SNF * 0,475 = 10.11 * 0.475 = 4.80 %
Proteins = SNF * 0,475 = 9.65 * 0,475 = 4.58 %
So, when calibrating the milk analyser we’ll use samples with the following
parameters:
milk fat
SNF
density
lactose
salts
proteins
I Ist sample
(low fat)
II nd sample
(high fat)
5,60
10,11
1,0352
4,55
0,76
4,80
9,80
9,65
1,0300
4, 34
0,72
4,58
5.3. For wheat, buttermilk and cream
Determination of fat content – Gerber’s method, described in Methods p. 3.4.
Density determination – using aerometer, described in Methods p. 3.3.
SNF determination – using drying - p. 3.3. and formula – p. 3.2.3.1.А
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APPENDIX 5: EASY CALIBRATION OF THE MILK ANALYSER BY
CALCULATING THE BASIC PARAMETERS VIA FORMULAS
DETERMINATION OF THE BASIC PARAMETERS IN THE MILK SAMPLE
BY USING FORMULAS IS NOT AS PRECISE AS USING THE ARBITRARY
METHODS, BUT IS SUITABLE FOR USAGE IN FIELD WORK.
5.1. Determination some of the parameters by formulas
There is dependence between the different parameters in milk and its
density, which may be expressed with mathematical equation. On this base
different formula, tested and confirmed by the classical laboratory methods
for analyses, are developed. We recommend the following:
5.2. SNF determination.
For determination of SNF the correlation dependence exists between the
milk’s density, fat and SNF in the milk. When the density and the fat are
known, the SNF can be calculated.
There are several formulas with different applicability.
А/ When the solids and fat are known
SNF is calculated by subtracting the fat percentage from the solids.
SNF = Solids – F (%)
Where
Solids
– solids in (%),
F
– fat content in (%),
This formula is used for determination of SNF in whey, buttermilk, and cream.
B/ Known quantity of fat and density (most commonly used method when
maximum accuracy is needed).
We recommend the following formula:
SNF =
0,075∗ F % + 100 −100/ density
0,378
This is a universal formula and actual for milk of almost all kind of cows and
sheep all over the world.
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5.3. Determination of lactose content
We recommend the following formulas:
А/ for cow milk
Lact. = SNF * 0,55 (% )
Where
SNF
– content of SNF in percentages (%),
0,55
– constant coefficient.
B/ for sheep milk
Lact. = SNF* 0,45 (% )
Where
SNF
–solids-non-fat content in percentages (%),
0,45
– constant coefficient.
This is an actual coefficient for sheep breeds on the territory of the Balkan
Peninsula.
5.4. Determination of salts content
We recommend using the following formulas:
А/ for cow milk
Salts = SNF* 0,083 (% )
Where
SNF
0,083
– solids-non-fat content in percentages (%),
– constant coefficient.
B/ for sheep milk
Salts = SNF * 0,075 (% )
Where
SNF
0,075
– solids-non-fat content n percentages (%),
– constant coefficient.
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This is an actual coefficient for sheep breeds on the territory of the Balkan
Peninsula.
5.5. Determination of total proteins content
We recommend using the following formulas:
А/ for cow milk
Protein = SNF * 0,367 (% )
Where
SNF
0,367
- solids-non-fat content in percentages (%),
– constant coefficient.
B/ for sheep milk
Protein = SNF * 0,475 (% )
Where
SNF
0,475
– solids-non-fat content in percentages (%),
- constant coefficient.
This is an actual coefficient for sheep breeds on the territory of the Balkan
Peninsula.
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APPENDIX 6 FREEZING POINT DETERMINATION
1. Methods for determination.
The milk analyzer determines the freezing point of each sample and the
quantity of added water. The milk analyser does not measure the freezing
point, but calculates it from the components it depends on. The basic
components in the milk are water, solids, lactose, FAT, proteins, minerals
(salts) and acids. The freezing point depends only on the diluted in the milk
components and quantity of the solvent (in the milk it is water). The ultrasonic
technology allows direct measurement of FAT, proteins, lactose + salts (the
soluble components, only influencing the freezing point), and the quantity of
the solvent in % is determined by 100 % – total solids %, total solids = lactose
% + FAT % + proteins % + salts % + acids %.
Without understanding the meaning of the freezing point – determined or
shown from the milk analyzer added water result easily may lead to a mistake
for the value of this parameter.
2. The basic freezing point.
Milk freezes at lower temperature than water. The average freezing point of
the raw milk in the most regions is at about -0,540°С. The average reading
for your region is called “basic” freezing point.
The freezing point of milk is a “physiological constant”. This does not mean
that it will not vary. In fact feed, breed, season, time of lactation, climate,
whether the sample is taken at the beginning, middle or end of lactation – all
these factors will have an effect on the freezing point of the individual sample.
This means that there is an average value of all these numbers. The more
samples used in obtaining this average, the more reliable it is as a base. Or
the basic freezing point is an average of freezing points of milk, taken from
many cows. When a laboratory checks a producer, it is only comparing the
average of the producer’s cows against a larger area average.
The Health authorities establish the basic freezing point or agriculture
departments in some regions, sometimes by universities, separate dairy
producers, or their associations. Frequently, tolerances have been
established on top of a basic freezing point to allow some variations in the
milk as well as device or operator variations.
Without mentioning the basic freezing point, the Association of Official
Analytical Chemists now recommends an upper limit freezing point at 0,525°C (2,326 standard deviations above the most recently determined
North American average of –0,5404°C), below which there will be at 95%
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confidence that will show 99% of all freezing point determinations on
unwatered milk:
“if the freezing point is –0,525°C or below, milk may be presumed to be free
of water or may be confirmed as water free by tests, specified below. If the
freezing point is above –0,525°C, milk will be designated as “presumptive
added water” and will be confirmed as added water or added water free by
tests specified below. Evaluate extreme daily fluctuations in the freezing point
of herd, pooled herd, or processed milk for presence of added water”.
“Presumed added water”, as described above, must be “confirmed” by means
of tests on authentic milk samples obtained as specified in the АОАС
METHODS.
After determination the freezing point of your sample via the milk analyzer,
the added water is calculated using the following formula:
AddedWater =
FrPo int Base − FrPo int Calc
∗ 100[%]
FrPo int Base
Where:
FrPointBase is the basic freezing point
FrPointCalc is measured freezing point
Note:
If the freezing point is not correctly determined, the result for the added water
is not valid. In this case results for FrPoint and AddWater are not shown on
the display and on the printout from the printer. If the density of the measured
sample is 0, the result for AddWater is not valid and is also not shown on the
display and the printouts.
Sample:
First variant
If you’ve entered for milk analyzer basic freezing point -0.520°C (according
article 5.9 of the EU Milk Hygiene Directive 92/46/ЕЕС), measured freezing
point –0.540°C, using the above pointed formula you’ll receive –3,8%.
Because it is not possible the added water to be negative value, the milk
analyzer indicates 0% added water. The reason for this is the tolerance in the
basic freezing point, reasons for which are described below.
If in the same milk we add 3,8% water, and the basic freezing point is the
same, the milk analyzer will measure freezing point –0.520°C, and will
indicate again 0% added water.
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Second variant
If you’ve entered for the device basic freezing point –0.540°C, measured
freezing point –0.540°C, the milk analyzer will indicate 0%. When you add
3,8% water, the device will indicate 3,8%-added water.
From the above mentioned follows that it is very important to enter correct
basic freezing point in the device.
The device’s results for added water may give information about doubt of
added water in the milk and the exact value of this added water may be
determined after a “cowshed sample” is taken and the result for the freezing
point, measured by the milk analyzer of the “cowshed sample” is entered as
basic freezing point in the formula for calculation of added water.
Then the result from this formula will give us the absolute value of the added
water for the corresponding milk supplier.
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1. FUNCTION........................................................................................................................................................................ 4
2. TECHNICAL CHARACTERISTICS ............................................................................................................................... 6
2.1. Working modes characteristics: ................................................................................................................................ 6
2.1.1. r1.1 Measurement mode milk / dairy product – first type.............................................................................. 6
2.1.2. r1.2 Measurement mode milk / dairy product – second type ....................................................................... 6
2.1.3. r1.3 Measurement mode UHT milk / dairy product – third type................................................................... 6
2.1.4. r2. Cleaning ........................................................................................................................................................... 6
2.2.
Measuring range: ................................................................................................................................................ 7
2.3.
Maximum permissible absolute error: ............................................................................................................. 7
2.3.1 Correct ambient conditions for optimal results of analysis. ........................................................................... 7
2.7. Connecting to 12 V DC power supply...................................................................................................................... 8
2.8. Connecting to IBM PC. ............................................................................................................................................... 8
2.9.Connecting a printer (option). ..................................................................................................................................... 8
2. THE ANALYZER AND ITS COMPONENTS............................................................................................................ 9
Fig. 1 Front panel................................................................................................................................................................. 9
Fig. 2 Back panel ............................................................................................................................................................... 10
Fig. 3 Principle working scheme ..................................................................................................................................... 11
Fig.4. Cable Description ................................................................................................................................................... 12
4. ANALYZER INSTALLATION...................................................................................................................................... 14
5. MAKING ANALYSES ................................................................................................................................................... 15
5.1 The milk sampling...................................................................................................................................................... 15
5.2. Making measurement ............................................................................................................................................... 15
5.3. Displaying the results................................................................................................................................................ 16
6. CLEANING THE ANALYZER...................................................................................................................................... 17
6.1. Periodically cleaning (rinsing) the analyzer .......................................................................................................... 17
6.1.1. Periodical cleaning frequency.............................................................................................................................. 17
6.1.2. Making the rinsing .................................................................................................................................................. 18
6.2. Complete cleaning..................................................................................................................................................... 18
6.2.1. Complete cleaning frequency .............................................................................................................................. 18
6.2.2. Cleaning ................................................................................................................................................................... 18
Fig. 5 Labels for the cleaning chemicals ................................................................................................................... 19
7. POSSIBLE MALFUNCTIONS AND ERROR MESSAGES, TROUBLESHOOTING ........................................ 21
8.1. Special (service) functions ....................................................................................................................................... 23
8.2. Function descriptions on their numbers: ............................................................................................................... 23
APPENDICES ................................................................................................................................................................ 29
APPENDIX 1 METHODS................................................................................................................................................... 29
1. Determination of milk's density................................................................................................................................... 29
1.1. General ........................................................................................................................................................................ 29
1.2. Sampling and preparation for analyses ................................................................................................................. 29
1.3. Basic principles. ......................................................................................................................................................... 29
1.4. Necessary devices and reagents ........................................................................................................................... 29
1.5. Making the determination:........................................................................................................................................ 29
1.6. Recalculating the values according lacto-density-meter at 20 oС. .................................................................. 30
2. Determination of fat content in the milk and milk derivatives................................................................................ 30
2.1. General ........................................................................................................................................................................ 30
2.2. Sampling...................................................................................................................................................................... 30
2.3. Basic principles. ......................................................................................................................................................... 30
2.4. Necessary devices and reagents ........................................................................................................................... 30
2.5. Making the determination:........................................................................................................................................ 31
2.6. Making measurement ............................................................................................................................................... 31
2.7. Calculating the results .............................................................................................................................................. 31
2.8. Measurement accuracy ............................................................................................................................................ 32
3. Determination of water content and solids in the milk and milk derivatives....................................................... 32
3.1. General ........................................................................................................................................................................ 32
3.2. Basic principles. ......................................................................................................................................................... 32
3.3. Necessary devices and reagents ........................................................................................................................... 32
3.4. Making the determination:........................................................................................................................................ 33
3.5. Making the measurement......................................................................................................................................... 33
3.6. Calculating the results .............................................................................................................................................. 33
3.7. Measurement accuracy. ........................................................................................................................................... 33
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4. Determination of casein content in the milk. ............................................................................................................ 34
4.1. General ........................................................................................................................................................................ 34
4.2. Sampling...................................................................................................................................................................... 34
4.3. Basic principles. ......................................................................................................................................................... 34
4.4. Necessary devices and reagents ........................................................................................................................... 34
4.5. Making the determination:........................................................................................................................................ 34
4.6. Making the measurement......................................................................................................................................... 34
4.7. Calculations ................................................................................................................................................................ 35
4.8. Measurement accuracy. ........................................................................................................................................... 36
5. Determination of salts in the milk ............................................................................................................................... 36
5.1. General ........................................................................................................................................................................ 36
5.2. Sampling...................................................................................................................................................................... 37
5.3. Basic principles. ......................................................................................................................................................... 37
5.4. Necessary devices and reagents ........................................................................................................................... 37
5.5. Making the determination:........................................................................................................................................ 37
5.6. Calculations ................................................................................................................................................................ 37
5.7. Measurement accuracy ............................................................................................................................................ 37
APPENDIX 2 REPRESENTATIVE SAMPLES FROM MILK AND OTHER MILK DERIVATIVES FOR MILK
ANALYSER’S CALIBRATION......................................................................................................................................... 38
1. General ....................................................................................................................................................................... 38
2. Necessary quality parameters values determination ......................................................................................... 38
2.1. Laboratory methods .................................................................................................................................................. 38
2.1.1. Determination of fat content ............................................................................................................................. 38
2.1.2. Milk density determination ................................................................................................................................ 39
2.1.3. Determination of total proteins......................................................................................................................... 39
2.1.4. Determination of casein content in the milk .................................................................................................. 39
2.1.5. Determination of salts in milk........................................................................................................................... 40
2.1.6. Determination of solids in milk ......................................................................................................................... 40
Express methods by using another milk analysers ..................................................................................................... 40
APPENDIX 3 MILK SAMPLING AND PREPARATION OF SAMPLES FOR ANALYSES....................................... 41
1. General ....................................................................................................................................................................... 41
2. Stirring the milk and its derivatives before sampling .......................................................................................... 41
3. Sampling..................................................................................................................................................................... 42
4. Sample preservation................................................................................................................................................. 42
5. Preparing the samples for analyses ...................................................................................................................... 42
APPENDIX 4 SAMPLING AND PREPARATION OF SAMPLES FOR VERIFICATION THE ACCURACY OF THE
MILK ANALYSER, MAKING CORRECTIONS AND RECALIBRATION.................................................................. 44
1. Necessary consumables and devices................................................................................................................... 44
2. General ....................................................................................................................................................................... 44
3. Representative Samples.......................................................................................................................................... 44
4. Samples preparation ................................................................................................................................................ 46
5. Advisable scheme for independently determination the content of different parameters in milk and its
derivatives....................................................................................................................................................................... 47
5.1. For cow milk (whole milk, low fat, skimmed milk) and UHT milk ...................................................................... 48
5.2. For sheep milk............................................................................................................................................................ 49
5.3. For wheat, buttermilk and cream ............................................................................................................................ 50
APPENDIX 5: EASY CALIBRATION OF THE MILK ANALYSER BY CALCULATING THE BASIC
PARAMETERS VIA FORMULAS .................................................................................................................................... 51
5.1. Determination some of the parameters by formulas ........................................................................................... 51
5.2. SNF determination. ............................................................................................................................................... 51
5.3. Determination of lactose content ........................................................................................................................ 52
5.4. Determination of salts content............................................................................................................................. 52
5.5. Determination of total proteins content.............................................................................................................. 53
APPENDIX 6 FREEZING POINT DETERMINATION ................................................................................................... 54
1. Methods for determination. ..................................................................................................................................... 54
2. The basic freezing point........................................................................................................................................... 54
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Lactoscan SLC, software version 42, LED display, software version 04,
Last edited: 04.04.2008
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