Vegan mayonnaise does not contain eggs so it cannot be marketed as mayonnaise, federal health regulators have said.

In a warning letter addressed to the Hampton Creek Foods dated Aug. 12, the U.S. Food and Drug Administration (FDA) said that the vegan-friendly and egg-less spread called Just Mayo that the health foods company markets violates the law because of misbranding.

"Based on our review, we have concluded that these products are in violation of section 403 of the Federal Food, Drug, and Cosmetic Act (the Act) [21 U.S.C. § 343] and its implementing regulations found in Title 21, Code of Federal Regulations, Part 101 (21 CFR 101)," the federal agency wrote in the letter addressed to Hampton Creek Foods CEO and founder Joshua Tetrick.

The FDA requires that products marketed as mayonnaise should have at least 65 percent vegetable oil and at least one egg yolk-containing ingredient. Hampton Creek's "egg" ingredient in its Just Mayo and Just Mayo Sriracha products though is merely a by-product of Canadian yellow pea.

In its letter, FDA said that the term mayo and image of an egg used by the products may mislead consumers as this may lead them to believe that these products are the standard mayonnaise.

The agency said that using the term "Just" along with "Mayo" gives the impression that the products are real mayonnaise regardless that these do not meet the standard definitions for mayonnaise.

The labels for these products do not contain eggs and these even contain ingredients that are not allowed by the standard identity for mayonnaise such as pea protein, modified food starch and beta-carotene that produces color simulating that of an egg yolk.

Hampton Creek likewise claims that its Just Mayo products are cholesterol-free. The labels used also give the impression that the product is healthy for the heart but the FDA noticed that the claims of Just Mayo being cholesterol-free are not authorized pointing out that this claim is not legitimate because the products have too much fat. The nutrition labels neither have the required footnotes.

Parke Wilde, from the Friedman School of Nutrition Science and Policy, concurs with FDA's views that the products are misleading.

"It's one thing to enjoy some of the halo for mayonnaise, but it's another to dupe consumers," said Wilde. "I think they're probably a little over that line with 'Just Mayo.' I can definitely see how it's a bit misleading."