RESUMEN
The contamination of honey with hepatotoxic pyrrolizidine alkaloids (PAs) is a well-known hazard for food safety. While management strategies and controls of the honey industry aim to reduce the PA levels, uncertainties remain with regard to the safety of regionally produced and marketed honey. In addition, a previous study showed large differences of results obtained after various periods of storage and apparent differences between the analytical results of different laboratories. Therefore, this study aimed at examining these uncertainties by monitoring the impact of storage on the PA and PA N-oxide (PANO) content of two freshly harvested honeys and on possible demixing effects caused by pollen settling. Additionally, three analytical approaches - target analysis with matrix-matched calibration or standard addition and a sum parameter method - were applied for a comparative analysis of 20 honeys harvested in summer 2016. All samples originated from Schleswig-Holstein in Northern Germany where the PA plant Jacobaea vulgaris is currently observed on a massive scale. The results of the time series analyses showed that PANO levels markedly decreased within a few weeks and practically reached the LOD 16 weeks after harvest. Tertiary PAs, by contrast, remained stable and did not increase as a consequence of PANO decrease. The experiments on a putative demixing, which may result in a heterogeneous distribution of PAs/PANOs, revealed that there was no such effect during storage of up to 12 weeks. A comparison of the PA/PANO levels obtained by different analytical approaches showed that in some cases the sum parameter method yielded much higher levels than the target approaches, whereas in other cases, the target analysis with standard addition found higher levels than the other two methods. In summary, the results of this study highlight uncertainties regarding the validity and comparability of analytical results and consequently regarding health risk assessment.
Asunto(s)
Contaminación de Alimentos/análisis , Miel/análisis , Alcaloides de Pirrolicidina/análisis , Incertidumbre , Calibración , Conformación MolecularRESUMEN
A general contamination of tea with pyrrolizidine alkaloids (PA) has just become known. Here, we report the application and modification of a new HPLC-ESI-MS/MS sum parameter method to quantitate PA content of herbal teas intended for infants, pregnant and lactating women. Using p-toluenesulfonyl isocyanate for derivatization and a stable isotope labeled internal standard, the total retronecine-/heliotridine-type PA content of the samples is expressed in form of a single sum parameter (retronecine equivalents: RE). The new methods were applied to analyze 44 tea samples for such consumer groups. Thirty eight products (86%) were tested PA positive showing PA concentrations ranging from 0 to 391 µg RE/kg (average: 50 µg RE/kg). The dataset is discussed in the view of the current discussion on PA in the food chain with special focus on those particular vulnerable consumer groups.