Occurrence of pyrrolizidine alkaloids in animal- and plant-derived food: results of a survey across Europe

Abstract

Pyrrolizidine alkaloids (PAs) are secondary metabolites of plant families such as Asteraceae or Boraginaceae and are suspected to be genotoxic carcinogens. Recent investigations revealed their frequent occurrence in honey and particularly in tea. To obtain a comprehensive overview of the PA content in animal- and plant-derived food from the European market, and to provide a basis for future risk analysis, a total of 1105 samples were collected in 2014 and 2015. These comprised milk and milk products, eggs, meat and meat products, (herbal) teas, and (herbal) food supplements collected in supermarkets, retail shops, and via the internet. PAs were detected in a large proportion of plant-derived foods: 91% of the (herbal) teas and 60% of the food supplements contained at least one individual PA. All types of (herbal) teas investigated were found to contain PAs, with a mean concentration of 460 µg kg−1 dry tea (corresponding to 6.13 µg L−1 in [herbal] tea infusion). The highest mean concentrations were found in rooibos tea (599 µg kg−1 dry tea, 7.99 µg L−1 tea infusion) and the lowest in camomile tea (274 µg kg−1 dry tea, 3.65 µg L−1 tea infusion). Occurrence of PAs in food supplements was found to be highly variable, but in comparable ranges as for (herbal) tea. The highest concentrations were present in supplements containing plant material from known PA-producing plants. In contrast, only 2% of the animal-derived products, in particular 6% of milk samples and 1% of egg samples, contained PAs. Determined levels in milk were relatively low, ranged between 0.05 and 0.17 µg L−1 and only trace amounts of 0.10–0.12 µg kg−1 were found in eggs. No PAs were detected in the other animal-derived products.