Study finds widespread adulteration of avocado oil

Avocado oil has become a staple in the kitchens of many people around the world, but a study suggests consumers are often being misled about their purity and quality.

Researchers at the University of California, Davis, have found that more than two-thirds (70 per cent) of a sample of 36 avocado oils were either rancid or mixed with other oils. Their study focused on private-label oils, which are made by a third-party processor and sold under a grocery store or retailer’s brand label.

“This process may lead to more adulteration and fraud due to the increased number of steps and parties involved,” write the scientists in the journal Food Control.

The team purchased the samples from 19 retailers in the US and Canada. Analysis revealed that 31 per cent of the samples were pure, and 36 per cent were of the advertised quality. That’s actually a slight improvement on a prior sampling study reported by the scientists in 2020, which found that 82 per cent were rancid or adulterated.

“We found that low-cost products indicate a higher probability for adulteration, but high cost didn’t guarantee purity or quality,” said Selina Wang, an associate professor in UC Davis’ food science and technology department, who co-authored the paper with Hilary Green, a postdoctoral researcher at the university.

Since the first study was completed, there have been efforts to develop avocado oil standards that could be used to protect consumers from being cheated by inferior products or confused by misleading labels. For example, the Avocado Oil Expert Group was formed in collaboration with the American Oil Chemists’ Society to discuss potential standards and future research projects.

However, “this study demonstrates that although progress is being made in standard development since our first market study in 2020, there are still issues with purity in avocado oil and these issues extend significantly into private label oils,” said Wang.

The researchers also identified certain chemical markers in avocado oil that professional retail buyers can use to make more informed decisions when it comes to choosing suppliers, including elevated stearic fatty acid value with an elevated delta-7-stigmastenol value.

Despite the findings, Wang insisted that she is “optimistic” about the future of the avocado oil industry.

“It’s a high-value product with high consumer demand, similar to what I saw with olive oil 10 years ago,” she said. “Olive oil quality and purity have improved significantly, which is where I see avocado oil going if we can establish fair standards and eliminate fraudulent products.”

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