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Вопрос:

Why readings of Klever differ significantly from the chemical analysis?

Without going deep into technical details, we shall describe why instruments of the Klever family, as well as any other milk analyzers, may yield deviations in results versus the chemical analysis performed using the Gerber technique (with the use of a centrifuge).

Only the deviations in measurement results, which in absolute value exceed the total error of the acid technique and the Klever analyzer, should be taken into account.

If the readings of Klever make a substantial difference from those of the “centrifuge”, we should note the following points.

For a start, perform maintenance of the instrument as per the guidelines of the operation manual. Then, make three measurements using distilled water. The third measurement should be regarded as check measurement. If the readings of the instrument produced using distilled water (the values of fat mass content, and NMS) are within ±0,04%, the result can be treated as satisfactory. Otherwise, the analyzer has to be warmed up within 5 minutes and the control should be repeated. In case the result of control is unsatisfactory after 3 additional measurements, then the analyzer needs zero adjustment.

You can also purchase our checking kit, to run a functional test of the analyzer and check the calibration characteristics.

If the analyzer check results are satisfactory, we as the manufacturing plant can guarantee that the instrument is fit for operation. In that case, note the sample which you are using for analysis.
Make sure the sample has undergone the required preparation.

The sample should be well mixed and degassed, with the temperature not exceeding the boundaries of the specified ranges. The sample for the Klever and the Gerber technique should be taken from one the same pre-mixed container.

You may be measuring a sample which is not suitable for the current calibration of the instrument (e.g., raw milk is used on the calibration for the reconstituted milk). Remember that in the base supply option the analyzer is calibrated for whole cow milk.

Then you should refer to the process of milk fat measurement using the Gerber technique. It should be carried out as per all the recommendations, in accordance with GOST 5867-90. Despite the seeming simplicity of the technique, there is quite a number of fine points which are not always paid due attention. Namely, they can bring in a substantial amount of systematic analysis errors (temperature mode, centrifuging time, isomeric composition of the isoamilic alcohol, etc.). Note the reading of the fat value taken from the cream gauge scale, excluding the incorrect rounding in either side.

Please run the chemical analysis as strictly and seriously as possible. As our practice has shown, it often happens that a discrepancy between the readings of the milk analyzer and the results obtained on the base of chemical analysis data occurs because of the incorrect implementation of the control analysis technique (the Gerbert technique).

 

Head of Laboratory for Chemical Analytical Research and Development

Yarovoy K.A.