Pret A Manger has put the blame for a second allergen-related death on coconut yogurt supplier Coyo just days after the company committed to overhauling its labelling.
The company confirmed that an unnamed customer suffered an allergic reaction after eating one of its vegan super-veg rainbow flatbreads in Bath. After further analysis, the yogurt substitute used by the company was found to contain milk protein.
In a statement, the company said: "We believe this resulted in the tragic death of a customer from an allergic reaction in December 2017..
Pret added that it had removed the product from stores following the incident, and was taking legal action. The yogurt was supplied by Coyo, a company founded by two former metropolitan police officers. The product was regularly used and recommended in recipes by Ella Mills - aka Deliciously Ella - and Nigella Lawson.
An investigation by the FSA and local authorities is confirmed to have taken place.
The Pret statement added: "Our deepest sympathies are with the family and friends of our customer in this terrible case and we will look to help them in any way we can."
Coyo denied responsibility, stating that the "dairy-free product we provided to Pret in December 2017, at the time of this tragedy, is not linked to the product we recalled in February 2018". It added the company would "continue to cooperate with all authorities and assist the inquest in finding the true cause".
It comes as the coffee shop chain commits to list all ingredients including allergens on its freshly made products following the death of 15-year-old Natasha Ednan-Laperouse who had an allergic reaction after eating a Pret sandwich.
The teenager collapsed on a British Airways flight shortly after eating a baguette purchased at the chain. She had suffered an allergic reaction to sesame baked into the baguette.
The presence of the sesame was not highlighted on the packaging or on the fridge of the Heathrow Airport outlet in 2016, an inquest into her death heard last month. The coroner found that Ednan-Laperous had been "reassured" by the lack of specific allergen information on the packaging.