Analysis of Swiss honeys for pyrrolizidine alkaloids

Various studies have shown that honey may contain pyrrolizidine alkaloids (PAs) and thus can pose a potential health risk for consumers. It seems that the level of contamination depends on the geographical and botanical origin of the honey. The geographically central location of Switzerland within Europe accounts for various different climate zones, and therefore can serve as a model to study PA contamination in honeys. We analysed 71 honeys between 2009 and 2011. Honeys from various botanical origins were collected from regions north and south of the Alps as well as the alpine regions. The PA concentration of the honeys was determined by target analysis using an HPLC-MS/MS-system, allowing the detection of 18 different PAs and PA-N-oxides found in the genera Echium, Eupatorium and Senecio. 54% of the honeys contained PAs, while in 46% of the honeys PA concentrations were below the limit of quantitation (LOQ). The LOQs ranged from 1 mu g/kg to 3 mu g/kg, depending on the PA. The mean PA concentration of the positive samples was 6.7 mu g/kg. The highest concentration of PAs (55 mu g/kg) was found in a honey from Ticino, an area of the southern flank of the Alps. All the other positive honeys contained PAs at concentrations below 18 mu g/kg. Therefore Swiss honey usually does not pose a risk for consumers. In the investigated honeys, honeys from the Swiss alpine regions (29 out of 37) tested more frequently positive for PAs compared to honeys from areas north of the Alps (9 out of 34). This probably reflects the different botanical settings of the central European and the alpine climate regions.