Confidence is vital
Milk data registration
The metering technology installed on milk collection tankers allows the
quantity of milk to be registered electronically, so that the milk collected
can be accounted for without the danger of any mix-up between the amounts
payable to different suppliers.
The reliability and accuracy with which the
volumes are measured are the decisive factors determining whether metering
devices on milk tankers will be given official approval through a “notified”
accredited body pursuant to EU Directive No. 2004/22 EC.
In Germany it is
the Physikalisch-Technische Bundesanstalt (PTB), the national metrology
institute in Brunswick, that is authorised to carry out OIML (French:
“Organisation Internationale de Métrologie Légale”) certification of the
components of a measuring instrument.
For approval under the Measuring
Instruments Directive (MID), the components of the device are required to have
OIML certification and the complete instrument must determine measurement
values with the prescribed degree of accuracy and reliability.
GEA Diessel
has been an expert in officially approved metering devices and plant for
decades, and its components are designed to comply with the requirements of
these Directives. Both the volumetric metering devices of the IZM-SE™ and IZM-TE™ series, and
now also the ZEVODAT-flash™
data capture and control unit, which has been available since the beginning of
2008, are OIML certified.
A measuring instrument that is approved under the
MID procedure and regularly checked by the weights and measures authorities
allows the supplier, the tanker operator and the dairy to be confident that the
whole sequence of transactions, all the way from the producer to the final
product, will be carried out in accordance with the principles of fair trading.
ZEVODAT-flash™ provides complete
documentation of all
processes
Quantity alone is not enough
How much the raw milk
supplied is worth depends on its quantity and its composition. The German
benchmark price is defined in terms of a product with 4.2% fat and 3.4% protein
content. Deviations from these proportions lead to deductions of some 0.3 to
0.4 cents for each 0.1% by which the fat and protein content actually
determined deviate from these figures. If the typical measuring tolerance in
determining the quantity is taken to be 0.5%, and that in determining the
constituents of the milk 0.05%, then on the basis of an assumed daily quantity
of 1,000 l, the sum at stake for the members of the supply chain is around
€2,000 a year. For a tanker with a capacity of 30,000 l, this makes up a total
amount of €60,000. Accuracy in the determination of the constituents is
therefore an important prerequisite for fair dealing and a good relationship
between partners.
The overall range of tolerance for these measurement
values is derived from the representative nature of the samples taken and the
accuracy of the measurements carried out in the laboratory. Recognised
laboratory devices of the type customarily employed show a tolerance of 0.02%
for fat content and of 0.04% for protein.
There are no in-line or on-line
measuring systems available on the market which will furnish the measurement
values reliably and with the required degree of accuracy directly on the
collection tanker during reception. Measurement in the laboratory therefore
remains as necessary as ever.
Samples of around 50 ml need to be taken for
this purpose. Although it is still standard practice in many countries to take
samples with a ladle, automatic sampling systems working on the peristaltic
principle have been installed on many vehicles for years already. GEA Diessel
offers a controlled hose pump system in the form of its PS3 device. In
association with a data capture system such as ZEVODAT-flash™, representative
samples are taken automatically throughout the entire reception procedure for
the expected quantity of milk. Uncertainties such as those arising through
manual sampling are thus virtually excluded. The PS4™ double-acting sampler can simultaneously take a sample of
each individual delivery and a cross-sectional sample of all the quantities
received during the whole tour. The volume of the tour sample is generally
around 500 ml. Thus the daredevil procedure of extracting samples of raw milk
from the top of the tanker by hand is a thing of the past.
GEA Diessel components are OIML certified
Traceability
The traceability of foodstuffs back to the
original producer is becoming more and more a focus of attention in quality
assurance circles. The taking of samples of individual and tour quantities
serves to ensure such traceability. GEA Diessel is now going another step
further with the development of a fully automated sampling system for milk
collection tankers. By eliminating the possibility of either deliberate
manipulation or unintentional error during sampling, the use of such a system
enhances the confidence placed in the process by all members of the supply
chain.
The vital features of the “SampleGuard™” automated sampler are:
• Highly
representative samples in relation to the entire quantity of milk received
• Avoidance of carry-over as between the samples from each individual
supplier
• Unambiguous and unmistakable assignment of samples to suppliers
• Reliable refrigeration of individual and tour sample bottles throughout
the tour
• Prevention of any possibility of manipulation
• Avoidance of
contamination of the samples through manual influence
Also of
importance is the size of the unit, since the modification of existing plant
can lead to substantial costs. In conjunction with the intelligent electronics
of the ZEVODAT-flash™ system, SampleGuard™ not only provides for the individual
control of sampling, but also constantly monitors and documents every case of
access to the cool box, and reports it to the operator by means of a protocol
(e.g. via GPRS). This substantially raises the threshold for any deliberate
interference with the sample.
The special and newly developed system for
monitoring the filling of the sample bottles, which is active during sampling
from the first to the last drop, is quick to signal any malfunction that may
arise in the reception procedure, and so allows it to be rapidly remedied. All
relevant data is stored in the data capture unit, and in addition is inputted
into the storage medium integrated in the sample bottle.
Creating confidence
The exact procedure by which raw
milk is accounted and paid for is laid down and monitored by law. Confidence in
the figures is enhanced if manual interference can be excluded. The fully
automatic system developed by GEA Diessel for the reception of milk at
collection tankers, with its complete registration of any events, offers every
possibility required in modern milk logistics.
The author
Hermann Hartmann, Dipl.Phys, GEA Diessel,
Head of Department for Mobile Technology and Components
Published in: International Dairy Magazine
02/09
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