Simultaneous detection of multiple mycotoxins allows food, feed, and grain operators to quantify aflatoxins, ochratoxin A, deoxynivalenol, zearalenone, fumonisins, and other regulated fungal toxins in a single analysis. Modern LC-MS/MS multi-analyte methods deliver high sensitivity, broad compound coverage, and cost-efficient compliance with international maximum limits. This technical article reviews sample types, target analytes, analytical methods, applicable standards, and practical applications of multi-mycotoxin testing in accredited third-party laboratories.
Technical Overview
Mycotoxins are low-molecular-weight secondary metabolites produced by filamentous fungi, mainly
species of Aspergillus, Penicillium, Fusarium, Alternaria, and Claviceps. These compounds are chemically stable, survive processing and storage, and exhibit carcinogenic, hepatotoxic, nephrotoxic, immunosuppressive, or estrogenic effects even at low microgram-per-kilogram levels.
Under field and storage conditions, a single crop is frequently contaminated by several fungal species at the same time, and a single fungus may produce multiple toxins. Co-contamination is therefore the rule rather than the exception, and combined exposure can produce additive or synergistic toxic effects. This reality, combined with increasingly strict maximum limits in China (GB 2761-2017), the European Union, the United States, and Codex Alimentarius recommendations, has driven the shift from single-analyte assays to simultaneous multi-mycotoxin methods.
The core analytical challenge is chemical diversity: target mycotoxins span a wide range of polarity, molecular weight, and ionization behavior, all within complex matrices such as cereals, nuts, and feed. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) operated in multiple reaction monitoring (MRM) mode has become the reference technique, enabling quantitative determination of 20 to more than 100 mycotoxins in one chromatographic run when combined with isotope-dilution internal standards.
Testing Samples
Cereals and Cereal Products
Wheat, maize, rice, barley, oats, rye, sorghum, and their processed products such as flour, bran, breakfast cereals, and noodles. Cereals are the matrices most frequently affected by Fusarium toxins (deoxynivalenol, zearalenone, fumonisins) and storage toxins (aflatoxins, ochratoxin A).
Nuts, Seeds, and Dried Fruits
Peanuts, pistachios, almonds, walnuts, sunflower seeds, figs, and raisins, where warm and humid handling conditions favor aflatoxin and ochratoxin A formation.
Feeds and Feed Ingredients
Complete formula feeds, premixes, soybean meal, corn gluten meal, and dried distillers grains with solubles (DDGS), which require monitoring of aflatoxin B1, zearalenone, deoxynivalenol, ochratoxin A, T-2/HT-2, and fumonisins for animal health and carry-over control.
Milk and Dairy Products
Raw milk, UHT milk, milk powder, and cheese, where aflatoxin M1 is the key marker of carry-over from contaminated feed.
Beverages and Stimulant Foods
Beer, wine, fruit juices, coffee, and cocoa, relevant for ochratoxin A, patulin, and Alternaria toxins.
Spices, Herbs, and Infant Foods
Chili, pepper, turmeric, nutmeg, and blended seasonings with elevated aflatoxin and ochratoxin risk, as well as infant formula and baby cereals subject to the strictest regulatory limits.
Testing Items
Typical simultaneous multi-mycotoxin panels include the following compound groups:
- Aflatoxins: B1, B2, G1, G2, and M1 (dairy)
- Ochratoxin A
- Type B trichothecenes: deoxynivalenol (DON, vomitoxin), nivalenol (NIV), 3-acetyl-DON, 15-acetyl-DON
- Type A trichothecenes: T-2 toxin, HT-2 toxin, diacetoxyscirpenol (DAS)
- Zearalenone (ZEN) and selected metabolites such as alpha-zearalenol and beta-zearalenol
- Fumonisins: FB1, FB2, FB3
- Patulin (fruit-derived products)
- Emerging and regulated additional toxins: sterigmatocystin, citrinin, enniatins A/A1/B/B1, beauvericin, Alternaria toxins (alternariol, alternariol monomethyl ether, tenuazonic acid, altenuene), and ergot alkaloids
Testing Methods
LC-MS/MS Multi-Analyte Determination
The primary method is high-performance or ultra-high-performance liquid chromatography coupled to triple-quadrupole tandem mass spectrometry. Samples are extracted with aqueous acetonitrile, often acidified with formic or acetic acid, followed by one of several cleanup strategies:
- Dilute-and-shoot: fastest workflow, suitable for low-complexity matrices, with matrix effects compensated by isotope-dilution quantification using 13C-labelled analogues
- QuEChERS-type extraction with dispersive SPE cleanup for rapid high-throughput screening and confirmation
- Immunoaffinity column cleanup for maximum sensitivity and regulatory confirmation of aflatoxins and ochratoxin A
- Multifunctional solid-phase cleanup columns for broad-spectrum mycotoxin purification in cereals and feed
Quantification relies on matrix-matched calibration or isotopic internal standards, with MRM transitions for each analyte providing both quantification and identity confirmation.
HPLC with Fluorescence Detection
Traditional confirmatory technique for aflatoxins (with pre-column, post-column, or photochemical derivatization), ochratoxin A, and zearalenone, offering robust performance where mass spectrometry is unavailable.
Immunoassay Screening
ELISA microplate kits and lateral-flow immunochromatographic strips provide rapid, low-cost screening at intake points, warehouses, and production lines. Presumptive positives are confirmed by LC-MS/MS.
Gas Chromatography Methods
GC-MS or GC-ECD after trimethylsilyl derivatization remains a legacy option for type A and type B trichothecenes, largely superseded by LC-MS/MS.
Applicable Standards and Performance Criteria
- GB 2761-2017: National food safety standard for mycotoxin limits in foods
- GB 5009.22-2016: Determination of aflatoxins B1, B2, G1, and G2 in foods (LC-MS/MS, HPLC-FLD, ELISA)
- GB 5009.24-2016: Determination of aflatoxin M1 in foods
- GB 5009.96-2016: Determination of ochratoxin A in foods
- GB 5009.111-2016: Determination of deoxynivalenol and its acetyl derivatives in foods
- GB 5009.235-2016: Determination of zearalenone in foods
- ISO 16050 and ISO 15141 series for aflatoxins and ochratoxin A in cereals
- EN 14123 and EN 14132 for aflatoxins and ochratoxin A in specific matrices
- AOAC Official Methods for mycotoxin determination in cereals, nuts, and feeds
- Commission Regulation (EC) No 401/2006 and Regulation (EU) 2023/915 defining method performance criteria and maximum levels in the EU
Typical validated performance includes limits of quantification from 0.01 to 5 µg/kg depending on analyte and matrix, mean recoveries of 70–120%, repeatability RSD below 20%, and coefficient of determination above 0.99 across the calibration range. ISO/IEC 17025 accredited laboratories support results with certified reference materials, matrix spikes, and regular participation in interlaboratory proficiency testing schemes.
Applications
- Raw material intake inspection at flour mills, feed mills, oilseed crushers, and food processing plants
- HACCP verification and process control for mycotoxin critical control points, including drying, storage, and sorting
- Compliance testing against Chinese national standards, EU maximum levels, FDA action levels, and Codex recommendations
- Import and export clearance support for grain, nut, spice, and feed consignments
- Storage and supply chain monitoring to detect deterioration and guide aeration, drying, or segregation decisions
- Carry-over studies tracing aflatoxin M1 from feed to milk and dairy products
- Epidemiological and risk-assessment research on multi-mycotoxin co-exposure in human and animal diets
- Due diligence and batch release testing by brand owners, traders, and retailers worldwide
FAQ
Why choose simultaneous multi-mycotoxin testing instead of single-analyte assays?
Co-contamination is common in real-world samples, and combined toxin exposure can be more hazardous than individual exposure. Multi-analyte LC-MS/MS covers all major regulated toxins in one run, reducing sample consumption, cost, and turnaround time compared with running several separate immunoaffinity or HPLC methods.
What detection limits can be achieved?
With isotope-dilution LC-MS/MS, limits of quantification typically range from 0.01 to 0.5 µg/kg for aflatoxins and ochratoxin A, and from 1 to 20 µg/kg for deoxynivalenol, fumonisins, and zearalenone, comfortably below the strictest infant-food limits in most matrices.
How are matrix effects controlled?
Ion suppression and enhancement are compensated by matrix-matched calibration, 13C-labelled internal standards, and effective cleanup. Method validation verifies recovery and precision in each specific matrix as required by ISO/IEC 17025 and EC 401/2006 performance criteria.
How much sample is required and how long does testing take?
A representative laboratory sample of 500 g to 1 kg is typically submitted, finely ground, and homogenized before subsampling. Instrumental analysis takes under 30 minutes per sample, and accredited third-party laboratories generally report results within 5 to 10 working days, with express screening available for urgent intake decisions.
Can a positive screening result from a rapid test strip be confirmed?
Yes. Lateral flow and ELISA results are presumptive; any positive or suspect finding should be confirmed and quantified by LC-MS/MS before regulatory or commercial decisions are made.
Which regulations define the limits my results are compared against?
Depending on the destination market, results are assessed against GB 2761-2017 and corresponding GB 13078 feed standards in China, Regulation (EU) 2023/915 in the European Union, FDA action levels and advisory levels in the United States, and Codex Alimentarius maximum levels for internationally traded commodities.