Subway has been facing a lawsuit regarding its so-called "100% tuna" since January of this year. Now a new version of the suit claims that lab testing has shown that the sandwich chain's tuna contains chicken, pork, and beef.

An earlier version of plaintiffs Karen Dhanowa and Nilima Amin's suit claimed that the chain's products were "bereft" of tuna, but that suit was dismissed by U.S. District Judge Jon Tigar in October.

Tigar argued that the plaintiffs had not proven that they had purchased Subway products based on a misrepresentation. He declined to pass judgment on the merits of the claims and instead gave Dhanowa and Amin a chance to file an amended suit.

Subway has released a statement saying that it will be asking the court to dismiss the suit, which the company calls "reckless and improper".

According to Subway, the plaintiffs have "filed three meritless complaints, changing their story each time." Subway stands by its claims that its products contain "high-quality, wild-caught, 100% tuna" that is strictly regulated by the government.

"That's right. The truth is, Subway uses wild-caught skipjack tuna regulated by the Food and Drug Administration (FDA)," a company site set up to defend its tuna reads. "A favorite among sub lovers, our tuna is and has always been high-quality, premium and 100% real."

Along with the site created for the purpose, Subway has been running tv ads defending the quality of its tuna. During a menu revamp this summer, the company declined to change its tuna saying an adjustment wasn't needed.

The recent version of the suit cites testing of 20 tuna samples from 20 Subway restaurants in southern California. The testing, conducted by a marine biologist, allegedly revealed that 19 of the 20 samples contained "no detectable tuna DNA sequences". According to the suit, all samples contained DNA from chickens, 11 contained pork DNA, and 7 contained cattle DNA.

In June of this year, the New York Times reported that it had conducted independent testing of Subway tuna and could not identify the species of fish present in the product. According to Reuters, this result means that the samples "were heavily processed or contained no tuna". The company, however, says that the results aren't so damning.

"The New York Times test results only show that the type of DNA test done by the unnamed lab wasn't a reliable way of determining whether the sample was tuna or not. If the test had confirmed the existence of a protein other than tuna, questions could have been raised," the company's site reads. "In other words, it was a problem with the test, not the tuna."