LABEC M-MIA-LA - Manual (Page 68)

Ultrasonic milkanalyser
Operation manual 04.11.09 66/107
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,