Session 3
A survey on the presence of undesirable botanic substances in feed in the European Union

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L. W. D. van Raamsdonk
RIKILT, The Netherlands

Directive 2002/32/EC of the European Parliament and of the Council of 7 May 2002 on undesirable substances in animal feed lists a range of substances from botanic origin (weed seeds) and additionally some chemical compounds directly originating from specific weeds.  In order to examine the actual status of enforcement and of the present occurrence of these botanic substances, a survey was carried out. A questionnaire was sent to 103 laboratories, including official control labs from all member states of the European Union. The results, indicating the frequency of occurrence as far as reported, are compared to the publications of the EU Rapid Alert System for Food and Feed (RASFF).

A total of 44 questionnaires were returned (42.7 %) from 22 member states. Ten member states predominantly from north-western Europe appeared to have an active monitoring of botanic undesirable substances. The questionnaire results did not indicate that the other member states enforce this part of Directive 2002/32/EC. Reports on the frequency of occurrence include: a few to 25-50 % of the samples contain traces of ergot (eight member states), a few to 24 % contain at least some traces of thorn apple (six member states), zero to 17 % contain some castor oil plant seeds (three member states), zero to a few samples contain Crotalaria seeds (three member states), and zero to 6 % contain traces of sareptian mustard (four member states). A few traces were found of the other mustard species, of croton and of Lolium temulentum. One member state conducted extra surveillance since several cases of animal intoxifications have been reported. In some cases a coincidence with undesirable botanic substances was found.

The current survey indicates that botanic undesirable substances do occur in certain frequencies. The occurrence in feed is supported by the reported cases of animal intoxifications. More specific data is desired. In order to evaluate the extent of the occurrence of the undesirable botanic substances, an effective monitoring of these substances in all member states for at least one or two years is recommended. Such a survey would need to include both macroscopic and microscopic examination to be ascertain that no material will be missed.

As far as the results of the current survey are considered, the following species could be included in a future list of undesirable botanic substances: rye ergot (Claviceps purpurea), thorn apple (Datura stramonium), castor oil plant (Ricinus communis), Crotalaria spp., purghera (Jatropha curcas), and croton (Croton tiglium). Some of these species might be included in a list of species containing alkaloids, if such a list will be raised. The problem of ragwort (Senecio jacobaea), whether or not as part of such a list, deserves special attention.
Besides these species a risk assessment of the other species currently on the list would be appropriate. The respondents considered it reasonable that some of these species can be deleted from the list. Additional species, such as Galium aparine, Polygonum spp. and Ambrosia spp. could be included in a risk assessment.
Microscopy is an effective technique for examination at macroscopic as well as microscopic level.

The development and application of chemical detection methods of the toxic compounds deserves encouragement. However, microscopic examination has its advantage for monitoring of emerging risks of new weed seeds and for all those listed seeds for which no chemical detection is available.

Four samples from the years 2005 and 2006 were mentioned in the questionnaires for rye ergot and for thorn apple with amounts at or over the legal limit (in both cases 1000 ppm). These findings are not listed in the RASFF notifications. The prevalence and origin of differences between actual results and RASFF listings require attention.
There is a desire for improving knowledge levels for the identification of botanic undesirable substances. This can be achieved by organizing training sessions, raising colleague networks as well as the development of dedicated expert systems.