A third sandwich and wrap manufacturer has recalled one of its products after an E coli outbreak that has left 67 people in hospital and more than 200 in total seriously ill.

On Sunday evening the Food Standards Agency (FSA) said This had “taken the precautionary step of recalling its This Isn’t Chicken and Bacon wrap because of possible contamination with E coli”.

The FSA said the company, which supplies the vegan meat-substitute wraps only to WH Smith, had not detected E coli in the product.

On Friday the Guardian revealed that Greencore, which supplies sandwiches, wraps and salads to many of the UK’s biggest supermarkets, had recalled 45 wraps, sandwiches and salads.

Samworth Brothers, which supplies Tesco and the One Stop convenience store chain, has recalled 15 lines of sandwiches and wraps.

The This wraps being recalled have a best before date of 18 June. Customers who bought one are asked to return it to WH Smith for a full refund, with or without the receipt.

A spokesperson for the FSA said on Sunday that investigations into the source of the E coli outbreak were continuing.

The recalled products are understood to contain a variety of salad leaf linked to the outbreak identified this month by the UK Health Security Agency.

The UKHSA has said it expected the number of people falling ill as a result of the outbreak to rise further as it carried out more research using genome sequencing to check which E coli cases were linked.

On Friday, Andrew Opie, the director of food and sustainability at the British Retail Consortium, said: “Retailers affected are taking swift action to remove these products from sale and are working closely with the Food Standards Agency to take any further action needed to minimise risk to their customers.”