LABEC M-MIA-LA - Manual (Page 74)

Ultrasonic milkanalyser
Operation manual 04.11.09 72/107
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 17 o T;
- 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
o С).
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.