LABEC M-MIA-LA - Manual (Page 71)

Ultrasonic milkanalyser
Operation manual 04.11.09 69/107
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
o С 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 cm
3 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.