A widespread investigation is underway after five patients died from listeria outbreaks believed to be linked to pre-packed sandwiches and salads consumed while in hospital.
Public Health England (PHE) announced on Friday that the number of confirmed cases of listeria had risen from six to nine following an earlier outbreak. Of those affected, five have died.
The first three patients died while being treated at Manchester University NHS Foundation Trust and Aintree University NHS Foundation Trust, while two further deaths were recorded last week at University Hospitals of Derby and Burton NHS Foundation Trust and University Hospitals of Leicester NHS Trust.
Additionally, Western Sussex hospitals NHS Foundation Trust, Frimley Health NHS Foundation Trust, and East Kent Hospitals NHS Foundation Trust have diagnosed listeria in cases linked to this outbreak, but have not reported any associated deaths.
PHE is continuing to analyse all recent and ongoing samples of listeria from hospital patients to understand whether their illness is linked to this outbreak
The deaths are being linked to the consumption of sandwiches and salads from the Good Food Chain. These have since been withdrawn from the hospitals when the links to the Listeria infections were first identified; and PHE is advising hospitals not to provide any Good Food Chain products to vulnerable patients while investigations continue.
The food company, which supplies to 43 NHS trusts across the UK, had been using meat produced by North Country Cooked Meats, which subsequently produced a positive test result for the outbreak strain of listeria.
"To date, there have been no patients linked to this incident outside healthcare organisations, but we continue to investigate," said Dr Nick Phin of Public Health England.
"Swift action was taken to protect patients and any risk to the public is low."
He added: "PHE is continuing to analyse all recent and ongoing samples of listeria from hospital patients to understand whether their illness is linked to this outbreak."
PHE is now working closely with the Food Standards Agency, NHS England and Improvement, as well as partner organisations in Scotland and Wales, to investigate the outbreak.
Listeria is a bacterium that 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, in this outbreak, the cases occurred in people who were already seriously ill in hospital and they are most at risk of severe infection.
To date, there have been no patients linked to this incident outside healthcare organisations, but we continue to investigate
Many types of food can become contaminated with listeria such as soft cheeses; chilled ready-to-eat foods like pre-packed salads, sandwiches and sliced meats; and unpasteurised milk products. Pregnant women are advised to steer clear of soft cheese for this reason.
To reduce the risk, the NHS advises people to keep chilled food in the fridge, heat food until it is piping hot, and not to eat food after its use-by date.
In a statement, the Good Food Chain said it was co-operating ‘fully and transparently with the Food Standards Agency and other authorities’, adding that it hoped the inquiry would be pursued with ‘urgency so the wider industry can learn any lessons as soon as possible’.