Bulteh 2000 EKOMILK Guia Del Usuario página 16

SOME REASONS FOR EKOMILK ACCURACY AND REPEATABILITY
DEVIATIONS
Below are described some reasons that may worsen the accuracy and re-
peatability of the EKOMILK Analyzers measurement results. Some informa-
tion about the way to avoid these problems is provided as well.
1. Aired milk - this is milk with a lot of tiny air bubbles inside. This air bubbles
are very small and it takes long time - from one to more than 10 or even 20
hours for these air bubbles to get out of the milk. This time depends on the
milk parameters and mainly on the milk Fat contents - the higher milk fat
contents is the longer time is required for the air bubbles to get out of the milk.
The ultrasonic method is not suitable for aired milk testing since the mea-
surement results are with significant deviations from the real values and
even in some particular cases the measurement can not be completed suc-
cessfully.
The milk becomes aired usually during the milk processing - milking, ho-
mogenization, UHT etc. but it can be aired even when the milk sample is
mixed if this is made by hard continuous shaking. This is why the sample
should be mixed smoothly and carefully.
There are two known methods that allow aired milk to be quickly recovered.
The first method requires the measuring mug with the milk sample to be
processed for about 10 to 15 seconds in an ultrasonic cleaning machine.
The cavitation phenomena of the powerful ultrasonic field removes the air
bubbles almost instantaneously. The other method requires the milk sample
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to be put under pressure - several kg/cm for about 10 to 20 seconds. Unfor-
tunately as you may note both methods require additional equipment but as
long as there are small inexpensive ultrasonic cleaning machines commer-
cially available it is easier to apply the first method if necessary.
2. Milk acidity - The ultrasonic method requires the milk sample to be warmed
during the measurement process. In case the milk has an increased acidity
a milk coagulation may occur when the milk is warmed and the measure-
ment results will have significant deviations from the real values and even in
some particular cases the measurement can be not completed success-
fully. For your reference the milk acidity of the milk sample must be less than
25°T for cow, buffalo and goat milk and less than 28°T for sheep milk.
Another issue is the milk coagulation contaminates the ultrasonic sensor
and it must be properly cleaned then.
3. Separated milk fat - If you try to test cool (refrigerated) milk which has
some milk fat/cream separated you will probably get wrong result especially
for the milk fat contents. In this case you need to warm up the milk up to 40 -
42°C first, mix the milk in order to solve the separated fat, cool it down to 20 -
25°C and then you can test it with the EKOMILK Analyzer.
4. Contaminated milk - Any solid particle with a size above 0.5mm may cause
measurement result deviations. This is why we recommend the milk sample
to be filtered before it is tested if there is a doubt the milk is contaminated.
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