Subway has hit back at claims that its tuna sandwiches contain no real tuna, labelling them as "baseless" and "misleading".
A report from The New York Times made the startling claims after commissioning a lab test which reportedly failed to identify the species in the popular sandwich chain's tuna subs.
More than 60 inches of tuna subs were tested in the investigation, with sandwiches purchased from three different stores in Los Angeles, which were then frozen and sent to a fish-testing lab for analysis.
The lab results concluded that, "No amplifiable tuna DNA was present in the sample and so we obtained no amplification products from the DNA. Therefore, we cannot identify the species."
A spokesman for the lab said the results pointed to two conclusions.
"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," the spokesman said.
Contacted by the Herald, a spokesperson for Subway in Australia and New Zealand says the claims made in the study are "baseless" and "misleading".
"Subway restaurants serve 100 per cent wild-caught cooked tuna, which is mixed with mayonnaise and used in freshly made sandwiches, wraps and salads," the spokesperson said.
"Claims to the contrary are baseless and misleading."
The New York Times article also indicated that DNA testing was not a reliable way to identify denatured proteins, like Subway's tuna, which was cooked before it was tested.
The claims follow the filing of a lawsuit by two customers in California, who accused the chain of fraud and false advertising over the contents of its tuna sandwiches.
The plaintiffs allege Subway had deliberately misled its customers by selling products "falsely advertised as tuna" in order to charge a "premium price".
The products "entirely lack any trace of tuna as a component, let alone the main or predominant ingredient", the plaintiffs have claimed.
However, the plaintiffs have not disclosed what they believed the sandwiches contained instead of the fish.
A Subway employee from the US told the Times she did not see what incentive Subway would have to replace the tuna with a substitute.
"I dealt with the tuna all the time," she said.
"The ingredients are right on the package and tuna is a relatively cheap meat. There would be no point in making replacement tuna to make it cheaper."
- With news.com.au