Grayanotoxins in honey

We offer detection on trace level

Aug 2023. As one of the few laboratories worldwide, the Competence Centre Honey of the Eurofins Food & Feed Testing laboratory network in Germany supports you in the analysis of grayanotoxins (GTX) in honey in accordance with the recommendations of the European Food Safety Authority (EFSA)^[1]. Due to our sensitive methods, GTX can already be detected on the trace level.

Occurence

Grayanotoxins belong to a group of plant toxins that occur in some genera of the Ericaceae family. Rhododendrons, for example, are among the Ericaceae that produce GTX. GTX-producing plants are particularly abundant in certain EU regions, including the Alps and Pyrenees, as well as non-EU regions such as Turkey.

Contamination of honey with grayanotoxins

Contamination of honey with GTX occurs when bees process nectar from grayanotoxin-producing plants during honey production. Thorough monitoring of blended honey sourced from EU and non-EU regions appears crucial, as the diversity of blends from various source honeys, each with different values of GTX, poses a potential contamination risk.

Toxicity

Among the approx. 20 natural grayanotoxins associated with honey, GTX I and III are the most toxic variants. When ingested orally in high doses, they can induce acute intoxication affecting the muscles, nervous system and cardiovascular function. This can lead to convulsions, mental confusion, and even heart failure. In addition, studies have demonstrated genotoxic effects, causing chromosomal damage in mice exposed to GTX I and III contaminated honey. The long-term effects on the reproductive system and the potential carcinogenicity of these toxins have not yet been adequately studied^[1].

Since there have been some repeated cases of poisoning by honey containing grayanotoxin, the Federal Institute for Risk Assessment (BfR) has reported on the occurrence of GTX in imported honeys from countries such as Turkey^[3].

Thresholds

Given the health risks that consumers may face from grayanotoxin-contaminated honey, the European Food Safety Authority (EFSA) has issued an Opinion Statement (No 2023-039)^[1]. This recommends the establishment of thresholds for grayanotoxins in honey, proposing a limit of quantification for GTX of 0.01 mg/kg or less.

Analysis

The Competence Centre Honey of the Eurofins laboratory network for Food and Feed Analysis in Germany offers the grayanotoxin analysis for honey in accordance with the EFSA recommendations. Our method includes GTX I as well as GTX III, utilising high-performance liquid chromatography coupled with mass spectrometry (LC-MS), which provides exceptional sensitivity for reliable detection of grayanotoxins in honey, even at trace levels.

Do you have any questions?

If you have any further questions regarding the analysis of honey, please do not hesitate to contact your personal account manager or directly our honey experts. We are looking forward to your enquiry.

Relevant sources:

[1] EFSA Journal: Risks for human health related to the presence of grayanotoxins in certain honey
[2] BfR FAQ: Selected Questions & Answers on Grayanotoxins in Honey
[3] BfR Opinion: Cases of poisoning through grayanotoxins in rhododendron honey originating
from the Turkish Black Sea Region