26 Apr 2010
DEVELOPING DETECTION METHODS FOR ALKALOIDS AND ERGOT BODIES

Regarding the alkaloids, the efforts in CONffIDENCE focus on the development of rapid methods of analysis to determine ergot alkaloids, pyrrolizidine alkaloids and tropane alkaloids in food and feed, and on the development of a near infrared imaging technique to rapidly detect and quantify ergot bodies in cereals.

 

Ergot alkaloids are mycotoxins, present in ergot, which may occur e.g. in grasses, grains and sorghum. These alkaloids are mycotoxins formed by the Clavicipitaceae, that cause effects as convulsions, gangrene and hallucinations, both in man and livestock. Pyrrolizidine and tropane alkaloids are plant toxins, occurring mainly in Senecio and Solanaceae species, respectively. They lead to adverse effects in humans and animals, and several human poisoning episodes have been described due to pyrrolizidine alkaloids, such as Gulran disease in Afghanistan in 2008, causing 50 fatalities. Current EU legislation limits the presence of certain alkaloid-containing botanical impurities in animal feed (and for ergot also in intervention wheat), but individual toxins are not yet regulated, whereas the European Food Safety Authority had recommended to establish legal limits for individual compounds in food and feed.

 

For all of these alkaloids, instrumental methods of analysis exist, but they have not been formally validated yet, whilst rapid methods for field testing are not available.  Within the alkaloids work package in CONffIDENCE, multiplex dipsticks are developed to rapidly and easily determine the ergot alkaloids ergotamine and ergocristine in cereals and feed, the pyrrolizidine alkaloids jacobine and lycopsamine in honey and feed, and the tropane alkaloids atropine and scopolamine in feed. Currently the activities are in the stage, where antibodies and test materials have been produced and the actual dispstick methodology is in development. The first results for pyrrolizidine alkaloids and tropane alkaloids look promising; for ergot alkaloids the experimental work will start soon.

Regarding the ergot study by NIR imaging, the last period was dedicated mainly to perform further analyses on the plane scan camera for the quantification of ergot in wheat and to setup the new on-line scan camera.To quantify ergot in cereals, 8 samples have been prepared including mixtures wheat/ergot at several concentrations from 0 to 1%, including 0.05% and 0.1% which are the limits in line with the current EU legislation, for ergot bodies in grains for human and in feed for animal consumption respectively. Three spectral libraries (ergot, wheat and background) were built and used for the development of discrimination equations. These equations were applied successively to all the pixels in the images of the 8 samples in order to build a mask, by isolating the ergots, and to calculate the number of pixels detected as ergots by grains quantity. Moreover, a proximity study was performed in order to remove the isolated pixels detected as ergot and to taking into account of groups of pixels detected as ergot only. The figure shows the results of the data treatment applied on one image and gives the counting results. Similar experiment is on going on a line scan camera using a larger wavelength range and performing quicker the analyses.
Information supplied by Hans van Egmond, RIKILT, NL, WP4a leader
Source : CONffIDENCE

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