SACRAMENTO, Calif., July 16, 2026 /PRNewswire/ -- A newly released UC Davis study has revealed systemic purity issues within the avocado oil product market, finding that 100% of analyzed salad dressings and U.S. mayonnaises labeled as "Made with Avocado Oil" were adulterated with other, less expensive oils. Additionally, 93% of evaluated avocado oil-labeled chips failed purity testing. Marianne's was identified as the benchmark for purity in the study, the 100% pure standard every brand was measured against.

Proof you can Trust - The recent 2026 UC Davis study builds on a landmark 2020 UC Davis study that examined the purity of avocado oils sold in the U.S. In that research, Marianne's was identified as one of only two brands meeting strict purity standards. Six years later, UC Davis researchers used Marianne's avocado oil as the benchmark for 100% pure, reinforcing the company's established position within the category while highlighting ongoing industry-wide issues with ingredient integrity.

"Consumers deserve to know exactly what is in their bottle and for too long, the avocado oil category has made that impossible. From day one, our promise has been simple: what is on our label is exactly what is in the bottle. The UC Davis findings show why that commitment matters more than ever." – Marianne Adams, namesake of Marianne's

Marianne's works directly with farming partners and manages the entire supply chain from sourcing through production. Every load of the company's avocado oil undergoes rigorous third-party testing, supporting a purity-first approach that has become central to the brand's identity.

Marianne's Redefines Purity - While most brands test only the fatty acid portion of CODEX standards, a threshold loose enough that oil can be adulterated by up to 40% and still pass, Marianne's tests every load against all three markers: fatty acid profile, sterol composition, and tocopherol levels. Marianne's is the only Seed Oil Free Certified® avocado oil available in grocery stores, with every load independently validated for purity. The brand is also a recipient of the Clean Label Purity Award, reserved for products that meet the highest standards of ingredient transparency, confirming Marianne's is free of the environmental contaminants and plasticizers increasingly found in the food supply. The result is what Marianne's calls the purity equation: 100% pure avocado oil + ultra clean oil = Marianne's, the highest bar in the category.

"When consumers reach for avocado oil, they are trusting that what is on the label is what is in the bottle. The UC Davis findings show that yet again trust is being broken. People are spending more on a product they believe is pure and in most cases, they are not getting what they paid for. Brands like Marianne's prove that transparency is possible. Consumers should expect nothing less." – Toby Amidor, award-winning registered dietitian and The Wall Street Journal best-selling cookbook author

To read the full 2026 UC Davis Study, visit: https://www.ucdavis.edu/food/news/avocado-oil-chip-youre-eating-may-not-be-made-pure-avocado-oil. For a full list of the 2026 UC Davis Study mayonnaise and salad dressing brands tested and results, visit: https://ucdavis.app.box.com/s/6ogs4l0ogplunooktwryr5b1m6k2xr9u.

For more information around purity, recipe inspiration, giveaways and more, follow Marianne's on Facebook, Instagram, LinkedIn and TikTok.

About Marianne's
Marianne's is a premium clean pantry brand built on five generations of family food expertise and an uncompromising commitment to purity and transparency. The brand's portfolio includes 100% pure avocado oil and beef tallow, ideal for high-heat cooking, baking, searing and everything in between. Named the benchmark for 100% pure avocado oil in the 2026 UC Davis Study, Marianne's is the gold standard against which every other product was measured. The brand holds the Seed Oil Free Certified® mark, third-party verification that its oil contains no seed oils or other adulterants, and is a recipient of the Clean Label Purity Award, confirming Marianne's is free of the environmental contaminants and plasticizers increasingly found in the food supply. Marianne's was also the first to bring Regenerative Organic Certified™ avocado oil to grocery shelves. Every load is third-party tested against all three CODEX purity markers (fatty acid profile, sterol composition, and tocopherol levels). For more information, visit www.mariannesharvest.com.

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SOURCE Marianne's Harvest