For decades, Subway restaurants have been serving up a menu of made-to-order sandwiches using a variety of cold cuts, proteins, and vegetables. Marketing has admonished consumers to “eat fresh.” But in the case of their tuna, it’s not totally clear what exactly people are eating.

According to an explosive new report in The New York Times, there’s reason to doubt the authenticity of their fish. Picking up on a January 2021 story in The Washington Post that detailed two angry consumers casting aspersions on Subway’s tuna, reporter Julia Carmel ordered a total of 60 inches of tuna sandwiches from three Los Angeles area locations, froze the meat, and then shipped it off to a laboratory to determine whether allegations over Subway using faux fish had any merit.

The lab—which asked not to be named in the article—performed a PCR test that looked for DNA from five different species of tuna. (According to the Food and Drug Administration, there are 15 species in total that can be labeled tuna; Subway claims to use only two, skipjack and yellowfin.)

The laboratory could not find any amplifiable tuna DNA in the sample—not skipjack, not yellowfin, or any of the three other species tested.

“There’s two conclusions,” a lab spokesperson told Carmel. “One, it’s so heavily processed that whatever we could pull out, we couldn’t make an identification. Or we got some and there’s just nothing there that’s tuna.”

To make matters more complicated, a similar investigation by Inside Edition found that the tuna samples were identifiably tuna.

There are several reasons why a lab may have had issues confirming the presence of tuna. According to Carmel’s article, cooking tuna may denature the DNA, rendering it undetectable. Another may be that Subway’s tuna supplier could be mislabeling the meat.

The curiosity over Subway’s tuna stemmed from a lawsuit filed in January in the U.S. District Court for the Northern District of California and reported by the Post in which two plaintiffs, Karen Dhanowa and Nilima Amin, allege that Subway is peddling a mixture “falsely advertised” as tuna. The complaint was later amended to argue it did not contain 100 percent sustainably caught skipjack and yellowfin tuna.

This isn’t the first time the company has come under fire for its products. In 2020, Ireland’s Supreme Court ruled its bread was not actually bread according to Ireland’s standards for tax-exempt bread. It contained 10 percent sugar relative to the amount of flour instead of the country’s required 2 percent, leading Twitter humorists to label their sandwiches “cakes with ham in them.” In 2014, the company was criticized for using the chemical azodicarbonamide, also found in yoga mats, in its bread.

On Thursday, June 24, the chain responded to a request for comment on the allegations from Fox Business by stating: "A recent New York Times report indicates that DNA testing is an unreliable methodology for identifying processed tuna. This report supports and reflects the position that Subway has taken in relation to a meritless lawsuit filed in California and with respect to DNA testing as a means to identify cooked proteins. DNA testing is simply not a reliable way to identify denatured proteins, like Subway’s tuna, which was cooked before it was tested."

[h/t The New York Times]