LABEC M-MIA-LA - Manual (Page 60)

Ultrasonic milkanalyser
Operation manual 04.11.09 58/107
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
o
С, the readings from lacto-density-meter are recalculated towards 20
o С.
Density recalculation towards 20 О С is done on the following way:
for every temperature degree over 20 О С 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
o С 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 сm 3 ;
- Pipettes from 1 and 20 сm 3 ;