Migliaccio & Rathod LLP is investigating whether consumers who purchased Sir Kensington’s mayonnaise marketed as made with avocado oil received products containing the type of oil represented on the product labeling.
Sir Kensington’s has sold mayonnaise products that emphasize avocado oil as an ingredient. For consumers who specifically seek mayonnaise made with avocado oil—or who seek to avoid conventional oils such as soybean or canola oil—the type of oil identified on the label can be an important reason for choosing one product over another.
Sir Kensington’s was among the brands included in a 2026 University of California, Davis study examining the authenticity of avocado oil used in processed foods.
The researchers tested 54 chips, mayonnaises, and salad dressings that identified avocado oil as the only oil ingredient. They found that 48 of the 54 products tested—89%—had oil compositions inconsistent with authentic avocado oil.
The results for mayonnaise were particularly concerning. Researchers tested 14 avocado-oil mayonnaise samples and found that 10 of the 14 samples, or 71%, were inconsistent with authentic avocado oil.
Why Consumers May Have Been Misled
Avocado-oil mayonnaise is often sold as an alternative to conventional mayonnaise made with other vegetable oils.
Consumers may specifically purchase these products because they:
- want mayonnaise made with avocado oil;
- seek to avoid soybean, canola, or other vegetable oils;
- perceive avocado oil as a premium ingredient;
- rely on the ingredient list when making dietary choices; or
- are willing to pay more for mayonnaise represented as using avocado oil.
If a mayonnaise product identified avocado oil as its only oil ingredient but contained an oil composition materially inconsistent with authentic avocado oil, consumers may not have received what they reasonably expected based on the product’s labeling.
UC Davis Finds Widespread Problems With Avocado Oil Mayonnaise
UC Davis researchers analyzed fatty acids and sterols—the chemical fingerprints of different oils—to determine whether oil extracted from finished products was consistent with authentic avocado oil.
The researchers also examined whether processing or emulsification could explain the unusual results and found only minimal changes in the relevant chemical markers.
Researchers additionally allowed a 10% margin for natural variation in authentic avocado oil.
Even with that allowance, 71% of the avocado-oil mayonnaise samples tested were inconsistent with authentic avocado oil.
The findings do not necessarily mean that a food manufacturer knowingly substituted another oil. UC Davis researchers have stated that adulteration may occur farther upstream in the supply chain and that manufacturers may unknowingly receive adulterated oil from suppliers.
Nevertheless, consumers may ultimately have paid premium prices for finished products that did not contain what they understood the labels to represent.
We Are Interested in Hearing From Consumers Who
- purchased Sir Kensington’s mayonnaise marketed as made with avocado oil;
- chose the product specifically because it contained avocado oil;
- relied on avocado oil being identified as the product’s cooking oil;
- sought to avoid soybean, canola, or other vegetable oils;
- paid a premium compared with conventional mayonnaise;
- purchased the product repeatedly;
- still have a jar or packaging showing a UPC, expiration date, or lot code;
- have receipts, photographs, or online purchase records; or
- would have paid less—or purchased another mayonnaise—had they known the oil might not match the product’s representations.
Because the UC Davis study examined individual products and samples rather than every product sold by each brand, product names, purchase dates, UPCs, expiration dates, and lot numbers may be particularly helpful.
If you purchased Sir Kensington’s mayonnaise marketed as made with avocado oil, we would like to hear from you.
There is no charge to speak with us, and there is no obligation to take legal action.
Please complete the contact form on this page, send us an email at [email protected], or call us at (202) 470-3520.
Migliaccio & Rathod LLP is a Washington, D.C.-based law firm that represents consumers in class-action litigation nationwide.