Image copyright Manchester University NHS Foundation Trust Image caption Two deaths occurred at Manchester Royal Infirmary

Three hospital patients have died in an outbreak of listeria linked to pre-packed sandwiches.

Public Health England (PHE) said the victims were among six patients affected in England and the deaths occurred in Manchester and Liverpool.

Two of the victims were at Manchester Royal Infirmary, with the other a patient at Aintree Hospital.

Sandwiches and salads from The Good Food Chain linked to the outbreak have been withdrawn and production stopped.

PHE said the products were withdrawn from hospitals when the links to the infections were first identified.

A spokesperson for the Manchester University NHS Foundation Trust said it offered its "deepest condolences to the bereaved families" and "sincerely regret" that two of their seriously ill patients contracted listeria.

The trust, which would not say when the deaths happened, said the sandwiches were from the patient menu.

The first patient showed symptoms on 25 April while the most recent case was reported on 15 May, a PHE spokeswoman said.

Aintree Hospital said: "Public health experts advised us of this supply chain issue on Friday 24 May and we immediately removed all products from this supplier."

Image copyright Google Image caption A patient at Aintree Hospital also died

Dr Nick Phin, deputy director at the National Infection Service at PHE said: "To date, there have been no associated cases identified outside healthcare organisations, and any risk to the public is low."

PHE said The Good Food Chain - which supplied 43 NHS trusts across the UK - had been supplied with meat produced by North Country Cooked Meats which subsequently produced a positive test result for the outbreak strain of listeria.

This business and North Country Quality Foods, which it distributes through, have also voluntarily ceased production.

A spokesman for The Good Food Chain Ltd said the company's production facility in Stone, Staffordshire, was "cross contaminated by an ingredient from one of its approved meat suppliers".

A spokesman for North Country Cooked Meats said it was "currently co-operating fully with the environmental health and the Food Standards Agency in their investigations".

What is listeria?

Listeria is a bacterium which can cause a type of food poisoning called listeriosis.

Normally, the symptoms are mild - a high temperature, chills, feeling sick - and go away on their own after a few days.

But these cases occurred in people who were seriously ill.

Along with pregnant women, newborn babies and the elderly, they are most at risk of a more serious infection that can spread to the brain or bloodstream.

In 2017 there were 33 deaths linked to listeriosis in England and Wales.

Listeria can be found in many types of food such as soft cheeses, chilled ready-to-eat foods like pre-packed salads, sandwiches and sliced meats, and unpasteurised milk products.

To reduce the risk, the NHS advises people keep chilled food in the fridge, heat food until it is piping hot and not eat food after its use-by date.