Hampton Creek, the manufacturer of eggless spread Just Mayo, has been warned by FDA that its products are in violation of federal standards and proper labeling. Specifically, FDA says the company’s plant-based product fails to meet the definition of mayonnaise, which requires eggs as an ingredient.

FDA sent a warning letter to the company earlier this month stating that after a review of San Francisco-based Hampton Creek’s products and website, regulators determined the products to be misbranded and found that its name and label could be misleading.

“The name ‘Just Mayo’ and an image of an egg are prominently featured on the labels for these products,” FDA wrote. “The term ‘mayo’ has long been used and understood as shorthand or slang for mayonnaise. The use of the term ‘mayo’ in the product names and the image of an egg may be misleading to consumers because it may lead them to believe that the products are the standardized food, mayonnaise, which must contain eggs.”

In addition, FDA says the use of the word “just” together with “mayo” reinforces the impression that the product is real mayonnaise, or “nothing but” mayonnaise.

“Additionally, the products contain additional ingredients that are not permitted by the standard of identity for mayonnaise, such as modified food starch,” FDA wrote.

Multinational consumer goods company Unilever, makers of Hellman’s mayonnaise, filed a lawsuit against Hampton Creek last year over the labeling of its “Just Mayo” products. Unilever alleged the company’s use and marketing of the term “mayo” in reference to its egg-free sandwich spread does not meet dictionary definitions. However, Unilever later withdrew the lawsuit after experiencing some consumer backlash.

 In response to the FDA letter, Hampton Creek CEO Josh Tetrick was quoted by the Associated Press as saying he had a good conversation with the regulatory agency and that he believes it is open to "sitting down and seeing if there's common ground.”