Fighting food fraud – a unique approach to tackle extra virgin olive oil adulteration

Significance of the Topic

Virgin and extra virgin olive oils are at high risk of adulteration due to their premium value and recognized health benefits. Ensuring authenticity supports consumer safety, prevents allergenic risks from undisclosed nut oils, and protects the integrity of the global olive oil market.

Objectives and Study Overview

This collaboration between the UC Davis Olive Center and Thermo Fisher Scientific aimed to establish a rapid and reliable screening method for detecting extra virgin olive oil adulteration and quantifying the level of cheaper vegetable or lower grade olive oils.

Methodology and Instrumentation

The approach relies on ultrahigh performance liquid chromatography with a charged aerosol detector to profile triacylglycerol composition. Sample preparation consists of simple dilution, eliminating lengthy extraction and extensive solvent use. Chromatographic peaks are automatically integrated and exported for multivariate analysis.

Instrumental Setup

• Thermo Scientific Vanquish Flex UHPLC system for high resolution separations
• Charged Aerosol Detector providing uniform response across nonvolatile species
• Chromeleon Chromatography Data System for instrument control, automation, and data transfer

Key Results and Discussion

The method successfully resolved characteristic triacylglycerol markers and differentiated pure olive oil from blends containing as little as five to ten percent adulterant. Principal component analysis plots demonstrated clear clustering of pure, blended, and blind test samples, confirming reliable detection at low levels of adulteration.

Benefits and Practical Applications

• Rapid analysis and high sample throughput for routine laboratory workflows
• Minimal sample preparation and elimination of toxic solvent disposal requirements
• Cost effective compared to mass spectrometry and classical sterol profiling
• Feasible for in-house quality control to reduce reliance on external testing

Future Trends and Applications

Ongoing efforts include expanding the sample library with diverse olive cultivars, geographic origins, and seasonal variations to enhance method robustness. The technique may be extended to other high value edible oils and additional chemical markers to broaden food fraud detection.

Conclusion

The UHPLC-CAD triacylglycerol profiling method offers a fast, accurate, and solvent-saving solution for authenticating extra virgin olive oil. Its sensitivity to low adulteration levels and straightforward implementation make it a valuable tool for industry and regulators.

References

• Green HS Li X De Pra M Lovejoy KS Steiner F Acworth IN Wang SC A rapid method for the detection of extra virgin olive oil adulteration using UHPLC-CAD profiling of triacylglycerols and PCA Food Control Volume 107 January 2020
• Thermo Fisher Scientific Application Note AN 73174 Determination of olive oil purity based on triacylglycerols profiling by UHPLC-CAD and Principal Component Analysis