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on January 3, 2008

Towards re-introduction of rendered products in the EU: Technology to identify specific animal proteins

Now, re-introduction of PAP for pig, poultry, and fish feeds is moving closer based on technology to identify ruminant-source meat-and-bone meal, etc.

In 2000, during the crisis of bovine spongiform encephalopathy or BSE, the European Commission introduced a total ban on the use of animal proteins in animal feeds. Regulators in Brussels needed time to carefully consider the risks, and especially the risk of transmissible spongiform encephalopathies (TSE) posed by the use of ruminant proteins. However, processed animal proteins, or PAPs, classified in regulatory Category 3 as sourced from food-grade non-ruminants, were established as safe for use as raw materials for animal feeds. Indeed, this was the premise on which the Commission based Regulation 1774/2002, which regulates the use of PAPs.

Despite this Regulation, many tonnes of animal protein derived from slaughter by-products from non-ruminant species have disappeared and continue to disappear into incinerators every day because the feed ban has not yet been lifted. Europe's animal feed industry is therefore losing a high-quality and cost-efficient source of protein. At the time it promulgated the ban, the European Union calculated that the disposal of animal protein and the use of alternative protein sources cost Europe almost 6 billion per year.

Added 'cannibalism' ban

Regulation 1774/2002/EC indicates that the use of PAPs as raw materials for animal feeds is not associated with any additional risks. However, the Regulation adds an ethical requirement, the ‘intra-species recycling ban' or ‘cannabalism ban'. In order to prevent cannibalism, PAPs derived from poultry must only be incorporated in pig feed and vice versa. Fulfillment of this requirement means that it must be possible to identify the species from which the animal materials are derived at any given moment in the feed production process. The EU will, in certain limited cases, accept written declarations to this effect. In the majority of cases, however, an analytical test is required.

Manufacturers of test kits have brought many tests to the market in recent years which can identify animal protein in PAPs and in animal feeds. The tests differ somewhat in their methodology and results. Most are designed to identify ruminant material, because this is where the greatest TSE hazard lies. At the initiative of the Dutch PAP producer Sonac and the specialist research centre CCL, a comparison has been undertaken of the available tests.


EU: Re-establishing the rendering cycleAt the initiative of the rendering industry, the Netherlands-based testing centre CCL has developed a reliable method for the validation of test kits for species identification. Such technology will give a major fillip to the re-introduction of animal protein in pig, poultry, and fish feedsthus helping to re-establish the rendered feed ingredient cycle in the European Union.

Validation method for ruminant material tests

The number of tests available for species identification is now so great that it is difficult to select the most suitable tests. Consequently, Sonac has taken the initiative, on behalf of the European Fat Processors and Renderers Association (EFPRA), to conduct a survey. CCL, based in Veghel (NL), was commissioned to undertake a systematic review of all of the available species-identification tests in Europe and elsewhere. The company consulted its international network of research institutes in the agricultural and food sectors and also performed an extensive literature study of tests for species identification in PAPs.

The survey yielded about 50 tests, based on around ten different detection techniques. No comparable data were available concerning the methodology, reliability, and economic viability of these 50 tests. CCL has produced a large number of reference materials for use in validating the tests. Meanwhile, EFPRA discussed the results with the EU's Joint Research Centre, which was called in to assist in this project by the Directorate General for Health and Consumer Affairs (DG Sanco).

Pure reference material

A species-identification test must be capable of identifying PAPs. However, the conditions during the rendering process are so extreme that the protein and DNA structures of animal material are substantially altered and partially degraded. By no means are all of the available tests still capable of identifying these proteins or DNA. Moreover, the production process consists of so many variables that there is no such thing as a standard end-product.

With Sonac's knowledge of the production process, CCL succeeded in producing reference material that covers most of the variables encountered in this process. A total of 180 well-defined reference samples were prepared. The samples are representative of the standard production process that is used to process bones, carcases, muscle, and intestinal tissue at temperatures of between 133˚C and 159˚C. Based on the reference material, it was possible to validate the species-identification tests.

At least three suitable tests

This standardisation process has made it easier to choose from among the range of available species-identification tests. CCL has made a pre-selection, from which three tests have emerged that are capable of identifying ruminant material in feed ingredients and finished feed with a detection limit of 0.1%. They are:

  • An ELISA-based screening test designed to detect specific animal proteins in feed; and
  • Two real-time, DNA-based PCR species-identification tests for PAPs.

The screening test for feed (ReVeal test from Neogen, Lansing, Michigan, USA) consists of a dipstick which is dipped in a feed extract. The appearance of lines on the strip 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 40 million. The purchase of alternative protein sources, such as imported soya, costs the Dutch animal feed industry 20 million per year. The re-introduction of PAPs for inclusion in feed would therefore provide a total annual saving of 60 million for the Dutch agribusiness sector.

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