Three supermarket chains have given confusing or incorrect information on allergens in their bakeries, the BBC Watchdog has found.

Branches of Asda, Sainsbury's and Tesco gave wrong or unclear details to the undercover reporters from the BBC’s consumer programme. The reporters visited 24 supermarket bakeries, five of which showed cause for concern. 

The retailers said they would review their labelling and staff training.

The EU says that consumers must be made aware when one or more of 14 particular allergens – including nuts, sesame, milk, eggs and wheat – is used as an ingredient in food products. In the UK, non-pre-packaged food does not need to be individually labelled on packaging, but stores must ensure clear and accurate information is readily available. 

In one Asda bakery, staff said an item did not contain the allergen sesame, when it was in fact listed as an ingredient for the product on the store's website.

In other Asda stores, the programme found staff were able to give a general warning that products may contain nuts or seeds, without being able to identify specific allergens contained within the recipe.

Reporters for the programme also found Tesco did list allergens on most of its products, but not for unwrapped bread rolls, paninis and pastries in some stores. At one branch, an undercover reporter posing as someone with a milk allergy found a senior member of staff who was unable to locate any ingredients information for an unpackaged panini that contained milk.

Sainsbury's did not list any of the 14 allergens on packaging or shelf labels in their in-store bakeries, but did tell customers to "ask a bakery colleague" about allergens. A staff member at one branch told an undercover reporter a raisin whirl was free of nuts – but when the staff member found a product information guide it listed almonds as an ingredient. 

Sainsbury's said it would update its labels "to include more specific allergen information".

Tesco said it exceeded "the current legal requirements", but in light of the Watchdog investigation a spokesperson said the food retailer would be "reviewing how allergy information is displayed moving forward".

Asda said in all the instances flagged up by Watchdog Live, its staff "ultimately advised the customer not to buy the product". But a spokesman added the supermarket was "also working to implement detailed allergen labels on our in-store bakery products".

The Watchdog Live’s report was shown on 7 November 2018 on BBC One.