Study finds high level of adulteration in avocado oils

A US study has found that four out of five samples of avocado oil sold commercially were either rancid or laced with other oils.

Researchers at the University of California, Davis, came to that conclusion after testing 22 domestic and imported avocado oil samples, which included all the brands they could find in local stores and online in the US.

“The vast majority of avocado oil sold in the US is of poor quality, mislabeled or adulterated with other oils,” according to the team, which says this is the first extensive study of commercial avocado oil quality and purity in the country.

Test samples included oils of various prices, some labeled extra virgin or refined. Virgin oil is supposed to be extracted from fresh fruit using only mechanical means, and refined oil is processed with heat or chemicals to remove any flaws.

The scientists – led by Selina Wang of UCD’s department of food science and technology – note that avocado oil is sold at a premium in the US by consumers interested in its purported health benefits and its distinctive flavour.

They produced their own avocado oil from fresh fruit to provide a baseline for comparison, as there are no standards available yet for the product. Standards are urgently needed to protect consumers and genuine producers, they write in the journal Food Control.

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“Because there are no standards to determine if an avocado oil is of the quality and purity advertised, no one is regulating false or misleading labels,” comments Wang.

“These findings highlight the urgent need for standards to protect consumers and establish a level playing field to support the continuing growth of the avocado oil industry,” she adds.

82 per cent of test samples were either stale before expiration date or mixed with other oils, and three samples - bottles labeled as "pure" or "extra virgin" avocado oil – contained near 100 per cent soybean oil, which is much less expensive to produce.

15 of the samples were oxidised (rancid) before their expiration date, and only two brands – Chosen Foods and Marianne's Avocado Oil, both from Mexico – were pure and non-oxidized.

The scientists received a $25,000 grant from Dipasa USA, part of the Dipasa Group, a sesame-seed and avocado-oil processor and supplier based in Mexico.

Avocado oil isn't the only product without enforceable standards. Honey, spices and ground coffee are other common examples. Foods that fetch a higher price are especially ripe for manipulating, especially when adulterations can be too subtle to detect outside a lab.

Wang is working to develop faster, better and cheaper chemical methods to detect adulteration so bulk buyers can test avocado oil before selling it.

She is also evaluating more samples, performing shelf-life studies to see how time and storage affect quality, and encouraging FDA officials to establish reasonable standards for avocado oil.