Chips, mayonnaise and salad dressings marketed as containing avocado oil may not always contain the pure ingredient shoppers believe they are buying, according to a new laboratory analysis from researchers at the University of California, Davis.
The peer-reviewed study, published in Applied Food Research, tested 54 avocado oil-labeled processed foods purchased from California stores and online retailers in 2025 and 2026. Researchers found that 48 products, or 89%, had chemical profiles inconsistent with pure avocado oil, even though avocado oil was the only oil listed as an ingredient.
The findings raise questions about ingredient verification and whether consumers paying a premium for avocado oil products are receiving what the package promises. They do not show that the other oils were unsafe, nutritionally inferior or harmful to health.
“Consumers are increasingly paying a premium for products made with avocado oil or olive oil,” lead author Selina Wang, a professor of cooperative extension in the UC Davis Department of Food Science and Technology, said in a news release. “They deserve to get what they pay for and food manufacturers deserve confidence that the ingredients they purchase from suppliers are authentic.”
The researchers analyzed 28 chip products, 14 mayonnaises and 12 salad dressings. They reported that 93% of the chips, 71% of the mayonnaises and all of the salad dressings tested contained evidence of oils other than avocado oil.
For comparison, the team also tested 20 processed foods labeled as containing olive oil. Only one failed the researchers’ purity assessment.
That difference does not necessarily mean olive oil fraud is rare across the entire market. The researchers noted that olive oil has been studied and monitored for decades, leading to more established testing standards and greater scrutiny throughout the supply chain. Avocado oil is a newer and generally more expensive product category with less developed oversight.
To determine whether the oils appeared authentic, the research team measured fatty acids and sterols, compounds that form chemical “fingerprints” characteristic of different oils.
Because frying, emulsifying and blending could potentially alter those profiles, the researchers also tested how common food-processing methods affected the chemical markers. They found that processing produced only minimal changes.
The team also allowed samples to deviate by as much as 10% from the expected avocado oil profile. That margin was intended to account for natural differences caused by factors such as avocado variety and geographic origin.
“In our experience we’ve noticed natural variables, such as geographic origin and avocado variety, can change these fingerprints,” Wang said. “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.”
The study could not determine which oils were added in every product or where the substitutions occurred. It also could not establish whether the brands selling the foods knew that the oil was not pure.
Food manufacturers may buy oils through third-party brokers or work with multiple suppliers. Without routine authenticity testing, a company could receive oil that has already been mixed with a less expensive oil before it reaches the manufacturing plant.
Wang said the adulteration likely begins with suppliers, though she also said food companies could do more to verify the ingredients they purchase.
“If consumers are buying potato chips that say they’re made with 100% avocado oil, that should be the product that they’re getting,” Wang said. “I don’t think there is enough accountability throughout the supply chain.”
The research does not mean every food package featuring the phrase “made with avocado oil” is necessarily misleading. Label language matters. A product may legally highlight avocado oil while also listing other oils in the ingredient list. The products included in this study, however, listed avocado oil as their only oil ingredient.
The study also represented only a portion of the market. Its 54 avocado oil products were not selected to create a nationally representative sample, so the 89% figure should not be interpreted as the exact failure rate for every avocado oil-labeled food sold in the United States.
Still, the results add to earlier concerns about avocado oil authenticity. Previous UC Davis research found evidence that many bottled avocado oils were either mixed with other oils or had deteriorated in quality. The new study suggests the problem may extend beyond bottles of cooking oil to processed foods that use avocado oil as a selling point.
For shoppers, ingredient lists remain useful but cannot reveal whether an oil has been diluted or replaced before manufacturing. Consumers do not have a reliable way to test authenticity at home, leaving food companies, suppliers, regulators and independent laboratories responsible for verifying that the contents match the label.
Salaries and benefits for two researchers were supported by startup funds from the University of California, Davis and UC Agriculture and Natural Resources. Discretionary funds from the UC Food Quality Lab paid for laboratory supplies and product purchases.