UC Davis Olive Oil Report: Top Imported Brands Fail Again

The UC Davis Olive Center’s second report on supermarket olive oil, released on 13 April, found that 73 percent of samples from the five top-selling imported “extra virgin” brands in the United States failed international sensory standards on two accredited tasting panels. The International Olive Council answered within a day, and not kindly. Here is what the study did, what it found brand by brand, and what the fight means for anyone buying a bottle.

What the study did

This is the follow-up to the July 2010 report that caused such a stir. This time the researchers, from UC Davis and the Australian Oils Research Laboratory, looked at fewer brands but more bottles of each: 134 samples of eight high-volume brands, bought in 2010 from supermarkets and big-box stores across California. Each oil went to two IOC-accredited sensory panels instead of one, and through the standard IOC chemistry tests for free fatty acids, peroxides, ultraviolet absorbance and fatty acid profile. Two newer tests used in Germany and Australia, diacylglycerols (DAGs) and pyropheophytins (PPP), were run as well. All testing was blind.

The study was paid for by Corto Olive, California Olive Ranch and the California Olive Oil Council, a fact the report states openly and critics were quick to repeat.

What it found

Taken together, 66 of the 90 samples from the five top-selling imports failed both panels, the same 73 percent failure rate those brands showed in the July 2010 study. The panels mostly found rancidity, which comes from oxidation, and fustiness, which comes from olives left to ferment before milling. The report is careful to say its results reflect oils bought in 2010 and should not be used to judge what is on shelves today.

The chemistry told a more awkward story. Every sample passed the IOC tests for free fatty acids, peroxide value and fatty acid profile, though several imported samples failed on ultraviolet absorbance. The German and Australian tests did much better at backing up the tasters: DAGs confirmed 65 percent of the negative sensory results and PPP 49 percent. Seventy percent of the top-selling imported samples failed the DAG test and half failed PPP. The researchers recommend that the IOC and the USDA add both tests to their standards.

How the trade reacted

The IOC’s new executive director, Jean-Louis Barjol, called the report the “same inexplicable criticism” and warned of “irreparable damage to the reputation of olive oil”, complaining of an “undercurrent of aggression” from researchers who use IOC-recognized panels and then turn them on IOC members. Bob Bauer of the North American Olive Oil Association said the domestic industry was using “subjective and rejected tests” to make imported oils look bad. The California Olive Oil Council called the findings further proof that consumers are unknowingly buying mislabeled oil.

Both sides have a point worth keeping. The funding came from Californians who stand to gain. The tasting panels were accredited by the very body now objecting. Neither fact makes a rancid oil taste fresh.

What it means for buyers

• Price was a poor guide. The California brand cost 46 cents an ounce, a cent less than Bertolli and Filippo Berio, and none of its samples failed. Colavita, one of the dearer imports at 61 cents, failed 56 percent of the time.
• The cheap tests pass almost everything. An oil can meet the acidity limit and still taste rancid. A low acidity figure on a label is not a freshness promise.
• Freshness is what failed. Look for a harvest date, a dark bottle, and a shelf that is not under a hot light, and use the oil within months, not years.

The UC Davis Olive Center has only existed since 2008, and California growers have been pressing the mislabeling argument for longer than that. This report will not settle it. It does make it harder to pretend the problem is imaginary.

Sources

• UC Davis Olive Center: Evaluation of Extra Virgin Olive Oil Sold in California, April 2011 (PDF)
• UC Davis Olive Center press release, April 2011 (PDF)
• California Olive Oil Council press release, 13 April 2011 (PDF)
• Olive Oil Times: Olive Council Denounces UC Davis Report’s “Undercurrent of Aggression”, 14 April 2011 (archived copy)