Food Literacy
A bag of chips that says “made with avocado oil” can cost several dollars more than the bag beside it. You are not paying that for the potato. You are paying it for one sentence on the front of the package.
In July 2026, researchers at the University of California, Davis published what happened when somebody checked sentences like that one. They bought packaged foods off American shelves, pulled the oil back out of the chips and the mayonnaise and the dressing, and read its chemistry against what authentic avocado oil looks like.
Forty-eight of the 54 avocado oil samples did not match. They ran the identical test on 20 olive oil samples from the same shelves. One failed.
That gap is the interesting part. Same aisle, same kind of company, same kind of promise on the front, and one category came back almost entirely clean while the other did not.
What the study actually found
The paper is Lopez-Alvarez, Li, Vizgordiski and Wang, “Authenticity of avocado and olive oils used as ingredients in commercially processed foods,” in Applied Food Research, 2026. It is open access, so you can read it yourself rather than take my summary for it.
Every oil has a chemical fingerprint. The fatty acids and the sterols, which are natural fat-like compounds in the plant, show up in ratios that are characteristic of the plant they came from. You cannot see it, taste it or smell it. A laboratory can read it.
The failures were lopsided by category. UC Davis reports that 93% of chips, 71% of mayonnaises and 100% of salad dressings tested came back inconsistent with authentic avocado oil.
The researchers allowed for natural variation. Selina Wang, the senior author, is quoted in the university’s announcement: “In our experience we’ve noticed natural variables, such as geographic origin and avocado variety, can change these fingerprints,” said Wang. “So we gave the samples some wiggle room, giving them a 10% margin of deviation to account for that, but 89% of the avocado products still failed.”
I cannot tell you how far a product had to miss, because the paper’s full criteria sit in a section I was not able to read. What the quote establishes is that a 10% allowance was built in on purpose.
A detail worth getting right. The 54 and 20 counts are samples, not shopping trips. UC Davis’s own media kit says two lots of each product were tested, so 54 avocado samples means 27 retail products bought twice, and 20 olive oil samples means 10 products bought twice. The results describe those particular lots on those particular shelves. They do not certify or condemn every package on sale today.
What “failed” does not mean
It does not mean there was no avocado oil in the product. It does not mean the food is unsafe. And it does not mean a brand knew.
Processed food companies commonly buy oil through suppliers. It is entirely possible to order avocado oil, pay for avocado oil and receive something else. I found no evidence that any specific company knowingly substituted anything, and I am not going to imply it.
Chosen Foods, one of the brands named, disputes the finding directly. In its own words:
“A recent UC Davis study suggests that two of our mayos and two of our dressings contain seed oils, which is simply not true. We never add seed oils of any kind. We believe the testing procedures used in this recent study do not fully account for the unique characteristics of finished products such as condiments and dressings.”
That is on the record and it belongs here.
What the result does establish is narrower: the oil recovered from most of those samples was not compositionally consistent with authentic avocado oil. Across the brand pages and certification lists I checked, I could not find a published test result covering a specific lot of any of these products, which is the practical problem this article is about.
I will say plainly what I am not doing here. Many people buy these products specifically to avoid seed oils. Whether that avoidance is worth doing is a separate argument that this study does not settle, and neither will I. The point stands without it: you paid extra for a named ingredient, and the testing suggests a lot of people did not get it.
Why olive oil passed
UC Davis offers an explanation, and it is worth quoting rather than paraphrasing. The university writes that “the gap between avocado and olive oil results reflects the fact that olive oil authenticity has been studied, tested and scrutinized for decades.”
That is the researchers’ reading, and it fits what is on the public record. It is an explanation rather than something this one comparison proves on its own, and I am going to treat it that way.
Here is what is checkable. To hold a category to its label you need an agreed definition of the real thing, laboratories that can run the test, and somebody actually running it on products people buy.
Olive oil has all three. There is an international Codex Alimentarius standard for olive oil, CXS 33-1981, adopted in 1981 and amended or revised eight times since, and it grew out of a 1970 recommended standard. The United States Department of Agriculture has published olive oil grade standards since 1948, most recently effective in 2010. Two trade programs test it, in different ways: one buys oil off store shelves, the other tests samples the producer submits.
Avocado oil got its first international standard on 25 November 2024, when the Codex Alimentarius Commission added it to the existing Standard for Named Vegetable Oils, CXS 210-1999.
One correction to how this is usually told: those are international standards, not national ones, and avocado oil did not get a standard of its own. It was written into a standard that already existed. In the United States the Food and Drug Administration has no standard of identity for avocado oil, and none for olive oil either. A standard of identity is the legal recipe for what a food has to be before it can use a name. A petition asking for olive oil standards, docket FDA-2022-P-1457, is still open.
Nor is there a loophole that makes a false label legal. Section 403(a) of the Federal Food, Drug, and Cosmetic Act, at 21 U.S.C. 343(a), where U.S.C. is the United States Code, the compiled federal statutes, says a food is misbranded if its labeling is “false or misleading in any particular.” The FDA even uses diluted olive oil as its own example of economically motivated adulteration, the term regulators use for cheapening a product on purpose for profit. The law is not the missing piece.
This is also not new. UC Davis reported in 2020 that at least 82% of the bottled avocado oil samples it tested were stale before their expiration date or mixed with other oils. Its 2023 study of 36 private label avocado oils found that 31% were pure and 36% were of the quality advertised. Those studies looked at different samples and measured different things, so they are three separate findings about the same category rather than one finding repeated.
How to check whether anyone actually tested it
This is the part you can use, and it works on any premium claim, not just oil.
1. Ask what kind of claim you are looking at. If the food is the ingredient, a potato, an egg, a bag of dried beans, then there is no separate ingredient claim to verify. Freshness and growing practice are still open questions; the identity of the thing is not. Most of the checking problem lives in processed products where a named ingredient is the reason for the price.
2. Look for a seal that means a laboratory was involved, then check the list. A seal is only worth something if you can look up who passed.
- Olive oil, national and store brands. The North American Olive Oil Association publishes its full certified list by name. In its own words, participants “must agree to have us randomly test their products regularly and repeatedly (at least 2x per year)” and the group samples “from store shelves.” Read the limits it states about itself too: it is members-only, product-specific rather than company-wide, and “It does not mean that we test every bottle or even every lot.”
- Olive oil from California. The California Olive Oil Council seal requires both a chemistry analysis and a blind sensory taste panel, repeated after every harvest, and it lists certified oils by year. Note the difference in method: here “each producer must first submit samples to a chemical laboratory,” so this one tests what the producer sends rather than what is on the shelf.
- Avocado oil. Nothing comparable. I looked for a trade association seal, a government program and a public testing directory, and found no equivalent to either olive oil program. The closest thing is Seed Oil Free Certified, a private trademark program founded in 2023 that does require lab testing and does publish a public directory. Three differences are worth knowing, and none of them is the fee, since the olive oil programs charge too. It tests samples an applicant submits rather than products bought off a shelf. It does not name its laboratory. And on the day I looked, its directory listed one avocado oil. In its own words it has “tested 22 avocado oil samples submitted as part of the Seed Oil Free Certified application process” and “Only 7 out of 22 met our purity standards.” It is a private organization’s own program built on its own criteria, not a trade body or a standards organization, and I am reporting that it exists rather than recommending it.
3. Ask the brand for a certificate of analysis. A certificate of analysis is a lab sheet for a specific batch. The clearest official definition I found sits in FDA guidance written for dietary supplement manufacturers, not for food companies or shoppers, so treat it as a useful description of the document rather than a rule that applies here. It says such a certificate should include “a description of the test or examination method(s) used, limits of the test or examinations, and actual results of the tests or examinations.” That is a fair standard to have in mind for what a real one looks like. Note what the guide does not do: it places no disclosure duty on a food company toward a shopper.
4. Prefer the category with the boring, decades-old rule. It is usually the cheapest way to be right.
How to ask, and how to read the answer
It is a short email. Something like:
Do you test each lot of this product for authenticity, and can you share a recent certificate of analysis? I am asking about the finished product, not the bottled oil.
That last sentence matters more than it looks. Chosen Foods says it tests every batch of the oil it produces, and its bottled oil did pass UC Davis testing in 2020. Its packaged products are what the 2026 study flagged. Same company, different production, different answer. A claim about a bottle is not a claim about the mayonnaise.
Then read what comes back against three questions.
- Did they send an actual document, or a paragraph? A lab sheet has a method, a limit and a number. A reply about a commitment to quality and excellence is not that. Be careful with the inference, though: a company can test carefully and still decline to publish, and plenty of support inboxes simply never answer. A document tells you something. Silence tells you very little.
- Whose document is it? Primal Kitchen’s public description is worth reading closely: its refiner “tests oil to ensure it meets Primal Kitchen’s specifications for fatty acid, sterols, and other physiochemical properties and provides a certificate of analysis (COA).” The certificate being described there is the refiner’s, which is to say the supplier’s own document, so calling that arrangement third-party testing is using the phrase loosely. Physiochemical properties, in the quotation above, just means measurable physical and chemical characteristics of the oil. On the pages I read, neither Primal Kitchen nor Chosen Foods publishes one.
- Does it cover the thing you are holding? A batch number on the sheet that matches nothing on your jar is a document about someone else’s food.
What I could not verify
Three claims are circulating with this study that I could not stand behind.
The paper’s methods and results sections sit behind a publisher block I could not get past, so anything that lives only in those sections is unread by me. That includes the figure that cooking moved the major fatty acids by less than 0.6 of a percentage point, which is being quoted as though it came from the study. It may well be in there. I have not seen it.
The specific oils named as substitutes in most coverage are not established for this study. UC Davis’s 2020 announcement about bottled oils named sunflower, safflower and soybean oil. That was a different study, and nothing I could read names the substitutes found in 2026.
And the count sometimes given as “19 of 22” olive oil products is wrong. Nineteen of 20 olive oil samples passed, and that cohort was 10 distinct products, each tested in two lots.
The sources, so you do not have to trust me
- The 2026 study, open access: Lopez-Alvarez et al., Applied Food Research, 2026
- UC Davis announcement, 2026, which links the media kit listing every brand tested
- UC Davis, 2020, bottled avocado oils
- The 2023 private label study and its UC Davis announcement
- North American Olive Oil Association certified list and method
- California Olive Oil Council, what the seal certifies, and its certified oils list
- The misbranding statute, 21 U.S.C. 343
- FDA on standards of identity
- FDA on economically motivated adulteration
- FDA’s definition of a certificate of analysis (written for dietary supplement manufacturers)
- Codex standard for olive oils, CXS 33-1981, whose own history box lists its revisions
- Food and Agriculture Organization of the United Nations (FAO) announcement of the November 2024 adoptions, where avocado oil was added
- USDA olive oil grades and standards
- Seed Oil Free Certified, a private trademark program: its product directory and its page on avocado oil testing, listed here because the article names it, not as a recommendation
- Chosen Foods’ response to the study
- Primal Kitchen on its avocado oil
Do this one thing.
Pick the single most expensive item in your kitchen that you bought for one named ingredient. The oil, the honey, the vanilla, the parmesan, the protein powder. One item.
Look it up on the certified list for its category if one exists. If none exists, send the brand the two-sentence email above and put a reminder in your phone for two weeks out.
Then see what comes back. If a lab sheet arrives, you have learned something specific about the product you are actually buying. If nothing arrives, you have learned only that they did not answer, which is worth knowing and is not the same as proof. Either way you now own a move you can use on every premium claim in the store, which is more than the front of the package was ever going to give you.
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