Dozens of pesto products from Italian sauce maker Sacla' are being recalled over fears they may contain peanuts without mentioning them on the label.
The Food Standards Agency has issued an allergy alert, warning that 25 pesto products may be affected.
The list of products also include own-brand jars of pesto from supermarkets Waitrose and Aldi.
The FSA said the products are a possible health risk for anyone with an allergy to peanuts.
Some customers who had bought any of the pesto jars through supermarkets have been emailed with the warning.
One woman was emailed by Morrisons to say: "Your shopping history shows that you have been sent one or more of these items. Anyone with an allergy or intolerance to peanuts should not consume this product."
In a statement, Sacla' UK's managing director Clare Blampied said: "The health, safety and welfare of our customers is our number one priority. We took immediate action to recall every batch of every Sacla' pesto recipe when we were made aware that some cashew nuts, which had been delivered by an external supplier, might contain traces of peanuts.
"Cashew nuts are an integral part of the pesto recipe and, therefore, we contacted all retailers to withdraw our pesto products straightaway from the shelves.
"Anyone who suffers from a peanut allergy should not consume any of these products, and return them to the store where they made the purchase, or contact Sacla' directly.
"We have launched an in-depth investigation into this unusual incident and we are working very closely with the Food Standards Agency. We are extremely sorry that this has happened and we are doing everything we can to resolve the situation as quickly as possible."
Important announcement from Sacla UK Ltd: pic.twitter.com/WiPLRMzI9X— Sacla' UK (@SaclaUK) December 21, 2019
Waitrose has confirmed it has recalled pesto products and said it was "very sorry for the inconvenience".
In a statement, the supermarket added: "Customers with a peanut allergy are advised not to consume any of these products of any date code and to return them to their local Waitrose for a full refund."
And a spokesperson for Aldi said: "Our supplier is recalling these two products because they may contain traces of peanuts which are not declared on the label. Customers with a peanut allergy should not consume these products and can return them to store for a full refund."
The list of products include:
- Waitrose Basil Pesto; Waitrose Cavolo Nero Pesto; Waitrose Chilli Pesto; Waitrose Essential Basil Pesto; Waitrose Essential Sun-Dried Tomato Pesto; Waitrose Rocket Pesto; Waitrose Tomato Pesto
- Aldi's Cucina Basil Pesto and Cucina Sun-dried Tomato Pesto
- Sacla' 'Nduja Pesto; Sacla' Reduced Fat Basil Pesto; Sacla' Reduced Fat Tomato Pesto; Sacla' Sun-dried Tomato Pesto 190g and 2x45g; Sacla' Truffle Pesto; Sacla' Vegan Basil Pesto 190g and 950g; Sacla' Black Olive Pesto; Sacla' Chargrilled Aubergine Pesto; Sacla' Classic Basil Pesto 90g, 190g, 290g, 950g and 2x45g; Sacla' Gift Pack Pesto Trio
The FSA said Sacla' had also contacted the "relevant allergy support organisations, which will tell their members about the recall".
It added: "If you have bought any of the above products and have an allergy to peanuts, do not eat them.
"Instead return them to the store from where they were bought for a full refund."
According to Allergy UK, peanut allergies affect around one in 50 children in the UK.
What are the symptoms?
The signs and symptoms of a peanut allergy can vary widely for each individual. Reactions usually occur within minutes but can take up to an hour to show.
Milder symptoms can include: itchy mouth, tongue or throat; swelling of lips, around the eyes or face; red raised itchy rash; vomiting, nausea, abdominal pain and diarrhoea; a runny nose and sneezing
More severe symptoms can include: swelling of the tongue or throat; difficulty in swallowing or speaking; a hoarse voice; becoming wheezy or persistent cough; noisy breathing; dizziness; sudden sleepiness in babies; becoming pale or floppy; collapsing or losing consciousness
Anaphylaxis is the name given to the most severe - and potentially life-threatening - reaction to an allergy.
The NHS website lists possible symptoms and offers advice about what to do if someone is showing the signs.
Source: Allergy UK