Pyrrolizidine Alkaloids
Pyrrolizidine Alkaloids-a Contaminant in Food
Pyrrolizidine alkaloids (PAs) are the secondary metabolites of plants. PAs are reported to be hepatotoxic, mutagenic, and carcinogenic. Pyrrolizidine alkaloids are well known contaminants of various foodstuffs such as leaf lettuces, cereals or honey. Recently pyrrolizidine alkaloids were also found in both herbal teas and common teas. Animal feedstuff can be affected as well. The source of the pyrrolizidine alkaloids are weeds from the families of the Asteraceae (genus Senecio, known as groundsel or ragwort), Boraginaceae and Fabaceae.
Maximum levels for pyrrolizidine alkaloids in the EU from July 2022
Aug 2020. By the end of June 2020, the Standing Committee of the EU Commission adopted a Draft Regulation setting maximum levels for pyrrolizidine alkaloids (PA) in foodstuffs. The new maximum levels will apply from July 2022 and will be included in the Annex of Regulation (EC) No 1881/2006 setting maximum levels for certain contaminants in foodstuffs. Foods that were lawfully placed on the market before July 2022, may continue to be marketed until the end of 2023.
Maximum levels were established for the following product groups:
- tea (including flavoured tea) and herbal tea
- food supplements containing herbal ingredients
- pollen (products) and pollen-based food supplements
- various dried herbs and borage
- cumin seeds
The maximum levels refer to the sum of 21 pyrrolizidine alkaloids and N-oxides and 14 additional pyrrolizidine alkaloids and N-oxides which may analytically interfere. The sum is calculated according to the "lower-bound" principle.
Occurrence in plants
An estimated 6000 plant species – which are 3% of all blooming plants – may contain pyrrolizidine alkaloids. The content depends on the plant species and part of the plant, additionally influenced by factors such as soil conditions and climate. The most relevant pyrrolizidine alkaloids producing plants are ragwort (Senecio jacobaea L.) and other members of the daisy family (asteraceae), the forget-me-not or borage family (boraginaceae) and the family of pulses (fabaceae or leguminosae).
Occurrence in food and feed
Pyrrolizidine alkaloids usually contaminate food and feed via PA-containing weeds. Lettuce, leafy vegetables, herbs, spices, tea, honey and pollen-based products, as well as borage oil, have long been known as potentially affected food groups. The German Federal Institute for Risk Assessment (BfR) has also reported the occurrence of pyrrolizidine alkaloids in pseudocereals in 2014. Pyrrolizidine alkaloids can also pose a serious problem in animal feed, especially in hay and silage, as the characteristic inherent odour of the specific plants is no longer noticeable for animals.
Toxicology
Pyrrolizidine alkaloids can cause liver damage and show genotoxic and carcinogenic effects in animal experiments with no safe threshold value being derived. In June 2020, the German Federal Institute for Risk Assessment published an updated Risk Assessment on pyrrolizidine alkaloids in foodstuffs in its statement 026/2020 (in German). New data from the years 2015-2019 show that the intake of pyrrolizidine alkaloids e.g. from honey, milk, spinach and especially tea and herbal tea has decreased in recent years. For food groups also relevant for PA intakes such as herbs, spices and food supplements, no conclusive statement could be made due to the lack of sufficient data. However, according to the BfR, there is reason to recommend continuing efforts to reduce the levels of pyrrolizidine alkaloids in food groups such as herbs and spices by improving cultivation, harvesting and cleaning methods.
Analysis of pyrrolizidine alkaloids
Our global experts from the Competence Center for Mycotoxins and Plant Toxins have many years of experience with LC-MS/MS analysis of pyrrolizidine alkaloids in all relevant food and feed matrices. Our participation in (inter)national committees has enabled us for years to continuously improve and adapt the analysis and evaluation of pyrrolizidine alkaloids to the latest legal/scientific status quo. In addition to the pyrrolizidine alkaloids to be regulated in the future, our analytical portfolio also comprises further pyrrolizidine alkaloids as well as the analysis of pyrrolizidine alkaloids under GMP conditions.
