Overview
ISO 14674:2005 (IDF 190:2005) defines a validated laboratory method for the determination of aflatoxin M1 (AFM1) in milk and milk powder. The procedure combines immunoaffinity chromatography (IAC) clean-up with thin‑layer chromatography (TLC) detection - commonly referred to as IAC‑TLC. It is applicable to raw milk, low‑fat or skimmed liquid milk and reconstituted milk powder. The method’s practical limit of quantification is close to 0.10 µg/L (for a 20 µL TLC spot); the smallest routinely detectable mass is 2 ng of AFM1.
Key topics and technical requirements
- Principle: AFM1 is selectively captured on an immunoaffinity column (antibody‑based), washed, then eluted and concentrated. The eluate is analyzed by one‑ or two‑dimensional TLC with UV visualization (365 nm).
- Performance: IAC columns must have ≥100 ng capacity and demonstrate ≥80% recovery when challenged with a 4 ng calibrant.
- Sensitivity: Typical LOQ ≈ 0.10 µg/L for liquid milk or dissolved powder (20 µL spot).
- Reagents & solvents: Chloroform, acetonitrile, methanol, diethyl ether, toluene and defined solvent mixes for extraction and TLC development; care with toxic solvents is required.
- Standards & calibration: AFM1 stock and working standards prepared and quantified spectrophotometrically (λ ≈ 365 nm) following the ISO/AOAC guidance in the document.
- Apparatus: Centrifuge, rotary evaporator or nitrogen concentrator, UV lamp (365 nm), silica gel TLC plates, spectrometer, and optional densitometer.
- Quality: Includes sections on precision (interlaboratory reproducibility, repeatability) and reporting requirements.
- Safety: Aflatoxins are carcinogenic and light‑sensitive; the standard warns about handling, light protection and validated decontamination procedures.
Applications and users
ISO 14674 is intended for:
- Dairy testing laboratories performing routine AFM1 monitoring in milk and milk powder.
- Food safety authorities and regulatory bodies verifying compliance with maximum residue limits.
- Quality control (QC) units in dairy processing and ingredient supply chains.
- Research labs studying mycotoxin occurrence, transfer and mitigation in dairy systems.
This method supports regulatory enforcement, risk assessment, and supply‑chain control for mycotoxin analysis, dairy safety, and AFM1 detection.
Related standards
- Sampling advice is referenced to ISO 707 / IDF 50 (sampling of milk), which is not part of the analytical procedure.
- ISO 14674 was prepared jointly with IDF and in collaboration with AOAC International; consult these bodies for complementary methods or alternative AFM1 procedures.
Keywords: ISO 14674, aflatoxin M1, AFM1, milk testing, milk powder, immunoaffinity chromatography, thin‑layer chromatography, IAC‑TLC, dairy laboratory method, mycotoxin analysis.