Lab analysis of Subway tuna sandwiches fails to identify tuna DNA

A lab test commissioned by the New York Times failed to identify any tuna DNA in a series of Subway tuna sandwiches.

Related: Subway bread is not bread, Irish court rules

A reporter acquired “more than 60in worth of Subway tuna sandwiches” from three Los Angeles storefronts, then engaged a specialized fish-testing lab. Researchers were unable to pinpoint a species.

“There’s two conclusions,” a lab spokesperson told the Times. “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.”

In February, when Inside Edition ran a similar test based on samples from New York, a Florida-based lab, Applied Food Technologies, did confirm the presence of tuna.

In January, when two California customers filed a lawsuit claiming the products “are made from anything but tuna”.

Instead, the plaintiffs alleged, the controversial comestibles are “made from a mixture of various concoctions”, ingredients “blended together … to imitate the appearance of tuna”.

Subway, which has more than 22,000 storefronts across the US, has has been dogged by legal action, including a class-action complaint that said its $5 foot-long sandwiches were in fact only 11 to 11.5in long.

It has fiercely defended the integrity of its tuna supply, calling the recent lawsuit “baseless”. Earlier this year, it touted its “100% real wild-caught tuna” on its website and offered a 15% discount on foot-long tuna subs under the promo code “ITSREAL”.

Related: Bread or unbread? Subway and other high street sandwiches reviewed

Earlier this month, the California customers who sued Subway walked back some of their more incendiary claims. But they still claimed “labeling, marketing and advertising” for Subway’s tuna products was “false and misleading”.

The headline-making case has sparked concern among consumers and responses from competitors. Other sandwich makers have pointed out that tuna is a relatively inexpensive meat, so Subway has little incentive to substitute a cheaper version.

Seafood experts have suggested Subway may not be to blame if its tuna is in fact not tuna.

“I don’t think a sandwich place would intentionally mislabel,” Dave Rudie, president of Catalina Offshore Products, told the Times. “They’re buying a can of tuna that says ‘tuna’. If there’s any fraud in this case, it happened at the cannery.”