By CBS 2 Chicago Staff

CHICAGO (CBS) — Now here is a lawsuit that’ll make you lose your appetite: Fast-food chain Subway is being sued for fraud, accused of selling tuna that isn’t tuna.

The lawsuit claims lab tests prove Subway’s tuna salad contains no real fish. Instead, it’s a concoction to imitate tuna.

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Attorneys for the plaintiffs in California say they are still conducting testing to determine exactly what ingredients are contained in the fishy mixture.

Lawyers are hoping to turn this into a class action lawsuit. Subway has not responded to a request for comment from CBS news.

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The chain’s ingredients have come under scrutiny in the past.

In 2014 the company said it was removing a chemical found in yoga mats from its bread. And Ireland’s supreme court recently ruled Subway’s bread is too sugary to even be called bread.

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Subway shops are everywhere in Chicago. There are at least eight of them in the Loop alone.

CBS 2 Chicago Staff