Traces of meat have been found in vegetarian and vegan prepared foods, an investigation by the Daily Telegraph has alleged.
The news outlet claims lab tests showed trace amounts of pork were found in Sainsbury's own brand 'meat free' meatballs, and traces of turkey in a BBQ Butternut Mac meal from Tesco's 'Wicked Kitchen' plant-based range.
A Tesco spokesman said the company 'takes the quality and integrity of our products extremely seriously and understand that our vegan and vegetarian products should be exactly that'.
They added: "Our initial DNA tests have found no traces of animal DNA in the BBQ butternut squash product available in stores today."
In addition, they said no turkey is handled on the site where the product is made. Tesco did confirm that the dish is made in a factory which handles meat, but added that 'strict controls' are in place to avoid cross-contamination.
Tesco Head of Plant-Based Innovation, and Co-creator of the Wicked Healthy line, Derek Sarno, told Plant Based News: "The media reports about vegan and meat-free products are concerning.
"Our own DNA tests have found no traces of animal DNA in the product available in stores today. The quality and integrity that go into our products are taken extremely seriously AND as someone who doesn't eat animals at all, I understand they should be exactly that, completely free from animals.
"I urge the Daily Telegraph to share the details of its findings so we can investigate further."
He added: "Whilst the allegations are not helpful, we mustn't let them dissuade us from our mission.
"In response, we can only work with the retailers that are making meat-free foods more widely available to remain vigilant and at the same time urge and encourage everyone else to continue to support those efforts and to encourage the retailers to do even more.
"Together we are making real and meaningful progress."
A Sainsbury's spokesperson added: "These products are produced at a meat-free factory. Sainsbury’s and the Vegetarian Society also carry out regular checks and no issues have been found. We are concerned by these findings however and are carrying out a comprehensive investigation alongside our supplier."
Animal charity PETA also commented on the findings, urging manufacturers to be vigilant. A statement by the organization said: "These findings will come as a massive shock to many – including, we suspect, those producing these foods.
"As the demand for vegan meats skyrockets, we urge manufacturers to improve their line-cleaning practices."
The news follows a number of major vegan/vegetarian launches in recent months, in response to growing consumer demand for plant-based food.
Last week, upmarket retailer Waitrose became the first UK supermarket to feature a dedicated vegan section, with a store buyer saying customers had been increasingly asking for meat-free options.
The Food Standards Agency [FSA] is investigating the Daily Telegraph's findings.
An FSA spokesperson said: "Our priority is to ensure consumers can be confident that the food they eat is safe and is what it says it is.
"We are investigating the circumstances surrounding these alleged incidents and any resulting action will depend upon the evidence found."