The maker of eggless spread Just Mayo has gotten a warning from regulators: Mayonnaise needs eggs.

The Food and Drug Administration sent a letter to the maker of the mayonnaise alternative earlier this month, noting that the product's name and label could be misleading. The FDA notes that mayonnaise must contain eggs, according to its standard of identity — and that Just Mayo does not.

"The term 'mayo' has long been used and understood as shorthand or slang for mayonnaise," the agency said in the letter to Hampton Creek, the maker of Just Mayo. The San Francisco-based company has positioned the spread as a healthier and more environmentally friendly alternative to mayonnaise.

Hampton Creek CEO Josh Tetrick said Tuesday he had a "really good conversation" with the agency earlier in the day and that he believes it is open to "sitting down and seeing if there's common ground."

Tetrick said he doesn't think the company will end up having to change its name.

"We feel good about where we are from a regulatory perspective, from a legal perspective," Tetrick said.

A representative for the FDA, Lauren Sucher, said the agency didn't have a comment beyond its letter.

The letter comes after Hampton Creek was sued last year by Unilever, the maker of Hellmann's mayonnaise, which also noted that Just Mayo doesn't contain eggs. Unilever ended up dropping its lawsuit after facing online backlash by Just Mayo supporters.

The letter from the FDA also noted that the Just Mayo contains ingredients that are not permitted by the standard of identity for mayonnaise, including modified food starch, pea protein and beta-carotene. It also said that the product are not qualified to make implied health claims that they can reduce the risk of heart disease, given the amount of fat they contain.

The letter, dated Aug. 12, said Hampton Creek should respond within 15 working days, and include actions it plans to take.