People with a peanut allergy have been warned to avoid eating products containing mustard because they may have been contaminated.

Mustard ingredients can be found in food such as dips, sauces, salads and pre-packed sandwiches, the Food Standards Agency (FSA) said.

Such mustard products could contain traces of peanut, potentially causing severe reactions for those with an allergy.

The agency is urgently working with the relevant local authorities, individual businesses and industry to identify which products may be affected.

“We have traced the contaminated mustard ingredients to a producer in India called GT Agro Industries and have identified one company who has supplied these ingredients for use in UK food,” the FSA said.

The UK company affected, FGS Ingredients Ltd, has advised customers to remove from sale products containing the contaminated mustard ingredients.

There is no evidence other suppliers are affected so far, the agency added.

“If mustard is present in a food, it should be labelled in bold on the packet because it is an allergen itself,” the FSA advised.

“If there is a risk that mustard could be unintentionally present in food there will be a ‘may contain’ label for mustard.

“If you are eating out, please ask the cafe or restaurant staff if any of their products contain mustard – by law, food businesses must provide this information to customers.”

FSA’s director of food policy, Rebecca Sudworth, said: “Those with a peanut allergy should avoid consuming products containing mustard as an ingredient until we identify the individual products affected.

“Parents and carers of children who have a peanut allergy should take care to check the labels of food they buy and, if eating out, or getting a takeaway, ask the restaurant or cafe about foods that might contain mustard.

“As soon as we have more information, we will update consumers. As always, we urge people with an allergy to sign up to our allergy alerts, so you can be notified about future allergy recalls.”