Report on the 2016 Proficiency Test of the European Union Reference Laboratory for Mycotoxins for the Network of National Reference Laboratories: Determination of tropane alkaloids in cereal products for infants and young children
Tropane alkaloids (TAs) are plant toxins that occur mainly in Datura, Atropa and Hyoscyamus sp, belonging to the Solanaceae family, besides a variety of other families such as Erythroxylaceae, Brassicaceae, Proteaceae, Euphorbiaceae, Rhizophoraceae, Convolvulaceae and Cruciferae. The TAs occur in all parts of the plants and botanical impurities have been found in a range of crops due to accidental contamination during harvesting. The intoxication via the food leads to anticholinergic effects (e.g. blurred vision, pupil dilation, dry mouth, vomiting, muscle spasms, tachycardia, etc.), culminating in severe intoxications and death.
The EFSA CONTAM Panel established a group Acute Reference Dose (ARfD) of 0.016 μg/kg body weight (b.w.) expressed as the sum of (-)-hyoscyamine and ( ) scopolamine, assuming equivalent potency. Infants and young children are the most exposed age classes as they consume a higher amount of cereal-based products per body weight. EFSA estimated that the dietary exposure of toddlers could be up to seven times the group ARfD.
Recently, two European legislation acts were published in this field: Commission Recommendation (EU) 2015/976, recommending the monitoring of tropane alkaloids in certain food categories, and Commission Regulation (EU) 2016/239, enforcing maximum levels of tropane alkaloids in certain cereal-based foods for infants and young children.
The EURL-Mycotoxins organised a proficiency test (PT) concerning the determination of atropine and scopolamine in cereal-based baby food, aiming to underpin and assess the measurement capability of Member States' (MS) laboratories. Particular focus was given to levels relevant for enforcement of legislation. Two samples were distributed to the participants: one sample labelled “C” – biscuits for infants containing approx. 1.2 µg/kg of atropine and 0.2 µg/kg of scopolamine, and one sample labelled “E” – cereals for porridge containing approx. 7.4 µg/kg of atropine and 1.0 µg/kg of scopolamine.
Forty-eight datasets from 18 EU MS laboratories were received. Overall, 81 % of the z-scores were in the range of -2 to 2 and 90 % were in the range of -3 to 3. For the lowest TA level (sample C) still 75 % of z-scores fell into an acceptable range (|z| ≤ 2), while the mass fraction of scopolamine was far below the target level of 1 µg/kg. In line with this observation, the vast majority of reported LOQs were below 1.0 µg/kg. The methodologies used by the participants can be clustered into three groups: the method supplied by the EURL; the RIKILT SOP A1070 and methods based on QuEChERS. The instrumental determination was by LC-MS/MS, with one exception (GC-MS). The recoveries reported by the participants were close to 95 %. No statistically significant dependence of the z scores on the analytical methodology was observed.
These results support the assumption that atropine and scopolamine can be reliably determined at the maximum levels proposed by the EU to ensure the protection of infants and young children's health using state-of-the-art analytical instrumentation.
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