Deoxynivalenol (DON), also known as vomitoxin, is a type B trichothecene mycotoxin produced primarily by the filamentous fungi Fusarium graminearum and Fusarium culmorum. It is one of the most prevalent mycotoxins in the global food supply, particularly in temperate cereal-growing regions of Europe and North America. DON belongs to the same class of Fusarium-derived trichothecenes as nivalenol (NIV), T-2 toxin, and HT-2 toxin, all of which share a common sesquiterpene backbone.
DON primarily contaminates cereal crops — wheat, barley, oats, maize, and rye — during pre-harvest infection by Fusarium head blight (FHB) or ear blight, favoured by wet and humid conditions during crop flowering. Contamination can also occur during post-harvest storage. DON is a protein synthesis inhibitor: it binds to ribosomes and impairs translational elongation, triggering the ribotoxic stress response. In humans and animals, toxic effects include nausea, vomiting (hence the name vomitoxin), feed refusal, immune system dysregulation, and reproductive toxicity at high exposures. The European Food Safety Authority (EFSA) has established a Tolerable Daily Intake (TDI) of 1 µg/kg body weight per day for DON.
DON is chemically stable and not destroyed by conventional food processing, including baking, extrusion, or cooking, though partial reduction may occur. This makes prevention through good agricultural practice (GAP) and routine analytical monitoring — such as Ovalab’s mycotoxin screening service — essential for the cereal industry.
Analytical Methods
- LC-MS/MS (Liquid Chromatography-Tandem Mass Spectrometry) — Multi-mycotoxin confirmatory reference method capable of simultaneously determining DON, its acetylated metabolites (3-AcDON, 15-AcDON), and nivalenol from a single extraction. Highly specific and sensitive; used for official control under EU contaminants legislation.
- HPLC-UV/DAD — High-performance liquid chromatography with UV or diode array detection. Historically the standard single-class method for DON; still widely used. Requires immunoaffinity column (IAC) or solid-phase extraction (SPE) clean-up. Less sensitive than LC-MS/MS for complex matrices.
- ELISA (Enzyme-Linked Immunosorbent Assay) — Rapid, high-throughput immunochemical screening method for DON. Commercially validated kits are available; suitable for large-volume incoming grain testing. Results above action limits require LC-MS/MS confirmation.
- Lateral Flow Immunoassay (LFIA) — On-site semi-quantitative test strips delivering results within minutes. Used in grain mills, port elevators, and at intake for rapid accept/reject decisions. Results must be confirmed by accredited laboratory analysis for official or regulatory purposes.
EU Regulatory Framework
Maximum levels for deoxynivalenol (DON) in food were originally introduced by Regulation (EC) No 1881/2006 and are now governed by Regulation (EU) 2023/915, significantly amended by Commission Regulation (EU) 2024/1022 (published 8 April 2024, applicable from 1 July 2024). The 2024 amendment lowered several existing DON limits and introduced maximum levels for new product categories. The EFSA Tolerable Daily Intake (TDI) for DON is 1 µg/kg body weight per day. Selected maximum levels:
| Product | DON maximum level (µg/kg) |
|---|---|
| Unprocessed maize (except for wet milling, except rice) | 1,500 |
| Unprocessed durum wheat | 1,500 |
| Unprocessed oat | 1,750 |
| Other unprocessed cereals | 1,000 |
| Maize-based breakfast cereals and cereal snacks | 400 |
| Other maize-based products for direct human consumption | 750 |
| Bread, pastries, biscuits, cereal snacks, breakfast cereals (non-maize) | 400 |
| Cereal flour and semolina | 600 |
| Dry pasta | 600 |
| Cereal-based infant and young children foods | 150 |
| Maize-based infant and young children foods | 150 |
Analytical method performance criteria follow the EU guidance document SANTE/2020/12830. All official control testing must be performed by ISO/IEC 17025 accredited laboratories.
Sources: EUR-Lex — Regulation (EU) 2023/915 | Commission Regulation (EU) 2024/1022
Frequently Asked Questions
What is deoxynivalenol (DON) and why is it called vomitoxin?
Deoxynivalenol (DON) is a type B trichothecene mycotoxin produced by Fusarium graminearum and F. culmorum fungi in cereal crops. It is called vomitoxin because one of its primary effects in pigs and other animals is vomiting (emesis) and feed refusal. In humans, even at subacute exposure levels, DON impairs protein synthesis by binding to ribosomes, triggering the ribotoxic stress response and causing nausea, gastrointestinal distress, and immune system disruption.
Which cereals are most affected by DON contamination?
Wheat (especially soft and durum wheat) and barley are the most frequently and severely contaminated cereals in Europe, primarily through Fusarium head blight (FHB) infection during flowering. Oats, maize, and rye are also commonly affected. Cool, wet conditions during crop anthesis are the main risk factors for Fusarium infection and DON accumulation. European cereal harvests are monitored annually through the EFSA-coordinated data collection programme.
Can DON be removed from cereals by milling or baking?
DON is chemically stable and is not fully eliminated by conventional food processing, including milling, baking, extrusion, or cooking. Milling reduces DON concentration in flour to some extent since DON concentrates in the outer bran layers (the flour fraction typically contains 50–80% of the original grain level). Baking may reduce DON by 10–70% depending on temperature and time, but cannot guarantee compliance if the raw material exceeds MRLs. Prevention through good agricultural practice and raw material testing is essential.
How is DON testing performed in a laboratory?
Accredited laboratories use LC-MS/MS as the primary multi-mycotoxin confirmatory method for DON and its acetylated metabolites (3-AcDON, 15-AcDON). ELISA-based kits are used for high-throughput screening of large grain batches. Lateral flow devices enable rapid on-site decisions at intake. Official control testing must comply with EU performance criteria (SANTE/2020/12830) and be conducted by ISO/IEC 17025 accredited laboratories. See Ovalab’s mycotoxin screening service for details.
What changed with Commission Regulation (EU) 2024/1022 for DON limits?
Commission Regulation (EU) 2024/1022 (applicable from 1 July 2024) amended the DON maximum levels in Regulation (EU) 2023/915. Key changes included: reduction of limits for unprocessed cereal grains, milling products, pasta, and cereal-based infant foods; new limits introduced for maize for popping/popcorn, ready-to-eat polenta, and foods for special medical purposes for infants. Products lawfully placed on the market before 1 July 2024 may remain until their minimum durability or use-by date.