Pyrrolizidine alkaloids in food: Downstream contamination in the food chain caused by honey and pollen

Till Beuerle (1) , Michael Kempf , Maximilian Wittig , Kirsten Schönfeld , Luise Cramer (1) , P Schreier

1 Institut f. Pharmazeutische Biologie

In recent years there was a steadily growing number of published data on pyrrolizidine alkaloids (PAs) in honey and pollen. This raises the question whether honey and/or pollen used as ingredients in food processing might provoke a downstream contamination in the food chain. Here we addressed two different facets in connection with PAs in honey and pollen. First we analyzed the PA-content of several food types such as mead (n=20), candy (n=10), fennel honey (n=9), soft drinks (n=9), power bars and cereals (n=7), jelly babies (n=3), baby food (n=3), supplements (n=3) and fruit sauce (n=1) that contained honey as an ingredient in the range of 5% to approximately 37%. Eight out of 60 retail samples were tested PA-positive, corresponding to 13%. Positive samples were found in mead, candy and fennel honey and the average PA-content was calculated to be 0.10 µg g-1 retronecine equivalents (ranging from 0.010 to 0.484 µg g-1). Furthermore, we investigated the question whether and how PAs from PA pollen is transferred from pollen into honey. We conducted model experiments with floral pollen of Senecio vernalis and PA-free honey and tested the influence of the quantity of PA pollen, contact time and a simulated honey filtration on the final PA-content of honey. It could be clearly demonstrated that the PA-content of honey was directly proportional to the amount of PA pollen in honey and that the transfer of PAs from pollen to honey is a rather quick process. Consequently PA-pollen represents a major source for the observed PA-content in honey. On the other hand, a good portion remains in the pollen. This fraction is not detected by the common analytical methods but will be ingested and represents an unknown amount of "hidden"-PAs. In addition, the results showed that a technically and legally possible honey filtration (including the removal of all pollen) would not be an option to significantly reduce the PA-level of the final product.

Mots clés: Life Sciences

Till Beuerle, Michael Kempf, Maximilian Wittig, Kirsten Schönfeld, Luise Cramer, et al.. Pyrrolizidine alkaloids in food: Downstream contamination in the food chain caused by honey and pollen. Food Additives and Contaminants, 2010, pp.1. ⟨10.1080/19440049.2010.521771⟩. ⟨hal-00633998⟩