Stop Buying Rancid Olive Oil

Since 2002, Clotilde and Yves Julien have been harvesting olives for their own olive oil at Olea Family Farm in Templeton, California. Over the years, they've seen the industry grow from a small handful of olive farms to "about 60 or 70 growers."

Which is why they decided to invent something that set them apart.

Their last five years worth of olives have been harvested using a personally-constructed "mobile olive mill" prototype. Forgoing the standard method of production -- where the olives are harvested, then transported to the mill, then finally pressed into oil -- this mobile mill allows olives to be converted into oil almost immediately.

"You get a much fresher oil," Clotilde told me. "The oil is very fresh and there's no damage to the oil by the mechanical harvester."

But other California-based olive growers are not the Juliens' only competition. In fact, 96 percent of the olive oil sold in America is imported from Europe. And a lot of people don't realize they're not the same. "There is still an education to be made for people to understand the difference between California olive oil and European olive oil," said Clotilde.

For instance, California olive oil has a very high burning point when compared to the European version, meaning it can be used to cook a wide variety of things without burning. Also, there are labeling considerations to consider. Olive oil created in Europe can receive an "extra virgin" label if only 20 percent of the oil inside is deemed to be "extra virgin." To receive the same label in California, 100 percent of the oil has to be "extra virgin."

There's also the fact that California olive oil is fresher, and that's not necessarily due to the extra length of time from the longer shipping route. "They send over what they have from the previous year," said Julien. "By the time it gets here, it's a year and a half old."

In fact, a lot of the olive oil that ends up on American shelves is rancid.

"A little over 70% of olive oil on the shelves currently is already rancid," said Lucas Murray, a UC Davis senior in biomedical engineering. "So, it doesn't contain the normal level of the antioxidants, nor the beneficial fatty acid profile." In other words, if you're buying olive oil for the health benefits, you're mostly wasting your money.

However, trying to keep rancid olive oil off the shelves is a futile act. Current test methods cost $600 and take two weeks. That price doesn't make sense for most consumers, and that time doesn't make sense for restaurants. (The oil would be used up by the time the results come back.) But Murray and fellow students at UC Davis may have solved that issue.

For this year's International Genetically Engineered Machines, an international competition which invites top students from colleges around the world to spend a summer devising solutions to real-world problems, a group of UC Davis students tackled the problem of testing for olive oil rancidity. Specifically, they developed a cheap test to examine the chemical profile of the oil. See, olive oils have chemical compounds called aldehydes that change over time. "There are different aldehydes in fresh and rancid olive oil," said Murray. "So we developed a way to look at this profile."

Best of all, the test costs only about $60, not including an extra "$2 to $3" for every test being administered. "We developed our test to be cheap and effective, as quality control at the end chain of the consumer level," said Murray. This means that supermarkets could theoretically test a batch of oil and make a promise to their customers that they're only receiving the freshest oil, not the rancid stuff that clogs up most shelves.

After the results of competition were tabulated, the UC Davis team came away with the grand prize award in what's known as the over-graduate division. (The team also won the Best Policy and Practices Advanced Presentation Award.) It's a big deal, in other words. So, don't be surprised if something like this is commonplace shortly.

In the meantime, there's another test you can use on their own when buying olive oil to avoid the rancid stuff. This one's free, even. Simply turn the bottle around and look for the "Made in California" label.