Scientists examine fingerprinting techniques to curb olive oil and pine nut fraud

Researchers at the University of Barcelona (UB) in Spain have investigated fingerprinting methods to prevent fraud in olive oil and pine nuts by verifying their geographical origins. The study aims to protect consumers and producers from fraudulent practices when such products reach the market and pose risks to consumer health in extreme cases.

Food fraud is an ongoing concern for the F&B industry, which is ramping up technological efforts to combat the rampant adulteration of various products. The olive oil supply chain, in particular, persistently ranks among foods with the highest fraud incidence, according to the EU Agri-Food Fraud Network, 2021.

The first study, published in Food Chemistry, highlights the potential of a method called “sesquiterpene fingerprinting” to verify the geographical authentication of virgin olive oil. The scientists say it is “emblematic” of the Mediterranean diet but particularly vulnerable to fraud. Falsification of the declaration of origin is especially difficult to detect.

The second, published in the same journal, uses the same analytical strategy to ensure the authenticity of pine nuts’ geographical and botanical origin.

“The traits and price of pine nuts vary according to the pine species and the region of origin. In this context, Mediterranean pine nuts get much higher prices than Asian pine nuts, which encourages fraudulent counterfeiting,” explain the researchers.

Comparing olive oil authenticity tests

The UB team collaborated with the Research and Innovation Centre of the Fondazione Edmund Mach and the University of Perugia in Italy to compare target stable isotope ratios analysis, a common method to test olive oil authenticity, and sesquiterpene fingerprinting for authenticating virgin olive oil origin.

Sesquiterpenes are naturally present in genuine olive oil. Their type and amount can vary depending on the variety, growth region, and oil processing method used. Matching the sesquiterpene pattern with the expected profile can help scientists identify if the oil was diluted, mixed, or falsely labeled.

Pine nuts are prone to mislabeling because their prices can vary depending on the pine species and region of origin.“The results indicated that the sesquiterpene fingerprinting method outperformed isotopic methods in reliability in several aspects, such as classification accuracy, sensitivity, and selectivity,” note the authors from the UB’s Department of Nutrition, Food Science and Gastronomy.

The scientists say that this biochemical technique needs to “increase the transferability” to ensure its global application and more effectively tackle counterfeiting in the food chain.

Tackling pine nuts mislabeling

Lower quality pine nuts are often mislabeled as premium due to the difference in prices from nuts in other regions.

The study’s findings indicate that monoterpene and sesquiterpene fingerprinting analyzed with solid-phase microextraction and gas chromatography-mass spectrometry, when combined with chemometrics, is a “fast and highly efficient system” for ensuring pine nut authenticity. 

“With almost no sample preparation, the methodology reveals 100% accuracy in distinguishing between pine nuts originating in the country and those from abroad,” says the team.

“In addition, it reaches 99% in the ability to differentiate stone pine (Pinus pinea) from different regions of Spain. This powerful and automatable tool represents a breakthrough in the fight against fraud and counterfeiting in the sector.”

Chemometrics uses mathematical and statistical methods to select optimal measurement procedures and analyze chemical data to provide the maximum relevant chemical information.

The UB researchers partnered with the Institute of Agrifood Research and Technology for this study.