Aside the official methods by light microscopy and PCR (for ruminant only), other alternative techniques may be used for the detection of PAPs in feed :
- NIRM (Near Infrared Microscopy)
- Mass spectrometry
- Combined methods
These alternatives are however not yet official for the evident reason that most of these methods are still in development and hence not yet validated.
One of the tasks of the EURL-AP is precisely to contribute to the development of new methods of analysis and the improvement of the existing ones. This represents a challenge as feeds deal with a huge diversity of ingredients and compounds that may interfere with results interpretation: for example dairy products which are authorised in feed for bovines will lead to a positive result with bovine and ruminant probes by PCR but usually will not be visible by light microscopy.
The role of the EURL-AP is therefore also to assess the potential of each analytical method.
Over the years numerous actions have been undertaken by the EURL-AP searchers for the development of methods.
- Development of new markers for the light microscopic method for the detection of animal proteins in feed (such as for insects)
- Build up of identification keys for Western European rodents hairs which are natural sources of contamination in feed
- Alternative light microscopic approaches (UV, DIC, DF, POL, Phase contrast)
- Development and validation of a new method for permanent microscopic slide preparation compatible with bone microstructural features
- Development of a robust quantification method requested for future partial lift of the total feed ban
- Development of real time PCR methods for the detection of animal proteins in feed
- Assessment and comparison of commercial immunoassay kits
- Potential of HPLC for the determination of protein weights in PAPs
- Development of mass spectrometry methods for the identification of proteins from animal tissues
- Development of a double sedimentation method for insect PAPs isolation
- Organisation of interlaboratory studies for method validation
Development of tools for searchers
As an integrated part of the development and research activities of the EURL-AP, other tools for scientific support are created. Those tools either serve the EURL-AP team and/or the NRL network.
Among the initiatives taken the most prominent ones are:
- Elaboration of a specific intranet platform for the NRL community towards a centralisation of the scientific services.
- Creation of an online micrograph collection (over 900 pictures).
- The development of a feed sample database management software (SMS for Sample Management System) for a large collection of animal feeds and ingredients.
- Creation and extension of a sample bank with focus on all possible animal by-products used or potentially usable in feed production. This collection notably includes:
- Single species products (e.g. meat and bone meals of pork, bovine and ovine origin, fish meals prepared from salmon, herring, insect meals…)
- Samples of PAPs produced by different processes (temperature, pressure, time, chemical treatment)
- Samples of PAPs from different geographical origins