Technology to identify specific animal proteins
indicates whether the feed contains ruminant proteins. The test gives
an instant result, but the percentage of false-positives is rather high. If
the test can be improved in this respect, it will be extremely useful.
The two PCR tests are capable of detecting whether PAPs contain
DNA material from ruminants. They are produced by CRA-W ( Walloon
Agricultural Research Centre, Gembloux, Belgium) and TNO (the
Organization for Applied Scientific Research, Zeist, the Netherlands).
Both tests have a low percentage of false-positive results. A third promising PCR test is also at an advanced stage of development in England.
Coming: EU ring test
Later this year, using data from the preliminary work conducted by
CCL, the European Joint Research Centre will organise a European
ring test for manufacturers of test kits for the identification of ruminant
tissues. More than 30 manufacturers and institutes in Europe and the
USA have expressed an interest in participating. The results are expected towards the end of 2006, whereupon it will become apparent
which tests are to be accepted by regulatory authorities in Brussels for
use in connection with the safe re-introduction of animal proteins as
raw materials in animal feeds. An important step will then have been
taken towards resolving this six-year impasse.
Resolution of the animal protein feeding ban portends significant
savings in multiple sectors. Each year EU rendering plants process
more than 2 million tonnes of slaughter co-products into Category 3
PAPs such as feather meal and non-ruminant meat-and-bone meal.
Since the total ban on the inclusion of animal protein in animal feeds,
however, PAPs have mainly been used as a fuel for power stations, as
fertiliser, or in petfood. However, the economic value of PAPs is many
times higher if they are used as animal feed ingredients.
For the Dutch meat industry alone—with an annual production in
2005 of 174,000 tonnes—PAPs have a production value of C40 million.
The purchase of alternative protein sources, such as imported soya,
costs the Dutch animal feed industry C20 million per year. The re-introduction of PAPs for inclusion in feed would therefore provide a total
annual saving of C60 million for the Dutch agribusiness sector.
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Further security: GTH as a
marker for risk material
A reliable means of species identification is a necessary prerequisite for the re-introduction of non-ruminant animal protein in
animal feeds in the European Union. However, a further condition
stipulated by the EU is that high-risk (Category 1 and Category 2)
animal materials must never find their way into Category 3 ‘
processed animal proteins’ or PAPs derived from non-ruminants fit for
human consumption. To prevent that happening, slaughterhouses
are adding visual markers to Categories 1 and 2 materials. However,
these markers are frequently not sufficiently stable to allow for the
detection of high-risk material after the rendering process.
CCL has investigated the stability of the current markers and
looked for alternatives. A review of markers revealed the favourable properties of GTH (glyceroltriheptanoate), a marker widely
used for ‘intervention butter’ (surplus production removed from
the EU market). GTH is not found in nature and is not toxic. Also,
it remains stable at high temperatures.
Because a large volume of material needs to be marked, the
cost of the marker is an extremely important factor. It was found
that the dosage of GTH could be substantially reduced after CCL
increased the sensitivity of the detection method. The availability
of this additional marker will assist in the safe re-introduction of
animal proteins in animal feeds. GTH has meanwhile been included
in trials by nine rendering plants in Europe.
