Subway ‘Tuna’ Is Not Tuna, Lab Analysis Finds

by : Emily Brown on : 22 Jun 2021 19:15
Subway 'Tuna' Is Not Tuna, Lab Analysis FindsPA Images

A lab analysis of a number of Subway’s tuna sandwiches failed to identify any DNA belonging to the fish. 

The investigation into the filling came following a lawsuit that claimed the popular sandwich restaurant’s tuna sandwiches are ‘completely bereft of tuna as an ingredient’ – an allegation Subway quickly denied.


The company responded to argue there was ‘simply no truth’ in the complaint that had been filed, saying in an email to The New York Times it delivers ‘100% cooked tuna to its restaurants, which is mixed with mayonnaise and used in freshly made sandwiches, wraps and salads that are served to and enjoyed by our guests.’

Subway tuna sandwich (Subway/Instagram)Subway/Instagram

In an effort to learn more about the tuna sandwiches, New York Times reporter Julia Carmel gathered more than 60 inches worth of plain tuna sandwiches from three different Subway locations around Los Angeles before freezing the filling and sending it to a commercial food testing lab that specialised in fish testing.

Using a PCR test, which rapidly makes millions or billions of copies of a specific DNA sample, the lab attempted to determine whether the substance used in the sandwiches included one of five different tuna species.


The US Food and Drug Administration states there are 15 species of nomadic saltwater fish that can be labelled as ‘tuna,’ though Subway says the chain only sells kipjack and yellowfin tuna, which would be recognised in a lab as Katsuwonus pelamis and T. albacares.

When the results came back, however, the lab stated, ‘No amplifiable tuna DNA was present in the sample and so we obtained no amplification products from the DNA.’

‘Therefore,’ the email read, ‘we cannot identify the species.’


A spokesperson from the lab explained there were two possible conclusions from the results, the first of which was that the filling is tuna, but that it’s ‘so heavily processed that whatever we could pull out, we couldn’t make an identification.’

The other conclusion is that ‘we got some and there’s just nothing there that’s tuna.’

Subway declined to comment on the lab results, though Carmel noted another publication tested Subway’s tuna sandwiches earlier this year and received results that confirmed the filling was indeed tuna.

Subway tuna sandwich (PA Images)PA Images

The reporter also explained the DNA of tuna becomes denatured when the meat is cooked, meaning the fish’s characteristic properties are likely destroyed, therefore making it difficult, if not impossible, to identify.

Though the results seem, for lack of a better word, fishy, the president of seafood market Catalina Offshore Products, Dave Rudie, has expressed belief it’s unlikely Subway would intentionally replace its tuna with something else.

He commented: ‘I don’t think a sandwich place would intentionally mislabel. They’re buying a can of tuna that says ‘tuna.’ If there’s any fraud in this case, it happened at the cannery.’

One Subway manager, Sage, told Carmel the restaurant receives its tuna in aluminium pouches containing a ‘pressed, vacuum sealed slab of tuna’ that employees then pull apart to create the flaky sandwich filling.


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Emily Brown

Emily Brown first began delivering important news stories aged just 13, when she launched her career with a paper round. She graduated with a BA Hons in English Language in the Media from Lancaster University, and went on to become a freelance writer and blogger. Emily contributed to The Sunday Times Travel Magazine and Student Problems before becoming a journalist at UNILAD, where she works on breaking news as well as longer form features.

Topics: Food, Fast food, fish, subway


The New York Times
  1. The New York Times

    The Big Tuna Sandwich Mystery