Clean-Up and Analysis of Aflatoxins and Ochratoxin A in Herbs and Spices

Significance of the Topic

The presence of aflatoxins and ochratoxin A in herbs and spices poses serious health risks and regulatory challenges. Monitoring these mycotoxins is essential to ensure product safety, protect consumers, and comply with international quality standards.

Objectives and Study Overview

This study presents a streamlined analytical procedure for simultaneous determination of aflatoxins B1, B2, G1, G2, and ochratoxin A in herbal supplements and spices. The goal was to develop a fast, sensitive, and reproducible HPLC method coupled with immunoaffinity clean-up and photochemical derivatization.

Methodology and Instrumentation

The protocol involves grinding samples and extracting with methanol–water and hexane, followed by NaCl-mediated phase separation. Immunoaffinity columns (Afla-OtaCLEAN) selectively retain target mycotoxins, and automated sample handling is achieved on an AcceClean workstation. Separation is performed on a C18 Mycotox column using a sodium phosphate–methanol–acetonitrile gradient. A UVE photochemical reactor enhances fluorescence for aflatoxins B1 and G1 without extra reagents. The system comprises a Thermo Scientific Dionex UltiMate 3000 HPLC with fluorescence detection configured for dual excitation/emission settings.

Main Results and Discussion

• Calibration curves for all analytes showed excellent linearity (R²>0.999) over relevant concentration ranges.
• Recovery studies in echinacea, ginger, and ginseng samples yielded 59–97% across five spiked mycotoxins, indicating effective cleanup and quantification.
• Immunoaffinity cleanup eliminated matrix interferences, ensuring accurate measurements.
• Photochemical derivatization improved sensitivity for aflatoxins B1 and G1, enhancing detection limits.

Benefits and Practical Applications

• The method delivers high sensitivity, precision, and minimal matrix effects for routine QA/QC.
• It is adaptable to a wide range of plant-based materials, including coffee, tea, juices, and essential oils.
• Automation accelerates sample throughput and standardizes preparation in analytical laboratories.

Future Trends and Application Opportunities

• Coupling with mass spectrometry for confirmatory and multi-residue analysis.
• Expansion to include additional emerging mycotoxins and broader analytical panels.
• Development of portable or on-site HPLC platforms for rapid field testing and screening.

Conclusion

The combined immunoaffinity cleanup and photochemical derivatization HPLC method offers a reliable, high-throughput solution for detecting aflatoxins and ochratoxin A in herbs and spices. Its robustness and adaptability support stringent quality control and regulatory compliance in the food and supplement industries.

References

• Ofitserova M., Nerkar S., Rasmussen W., Pickering M. Clean-Up and Analysis of Aflatoxins and Ochratoxin A in Herbs and Spices. Pickering Laboratories, Inc. Application Note 115.
• Sigma-Aldrich Co. Supelco Aflatoxin Mix and Ochratoxin A standards.
• LCTech GmbH. Afla-OtaCLEAN and UVE Photochemical Reactor product literature.