Two more patients have died after eating pre-packaged sandwiches and salads connected to a listeria outbreak, taking the total number of deaths to five, Public Health England said.
All affected patients ate products believed to be involved in the outbreak before 25 May.
The first three victims who died were at Manchester University NHS Foundation Trust and Aintree University Hospital NHS Foundation Trust in Liverpool.
It is understood that of the latest two listeria deaths, one died after the first three confirmed cases.
The other patient died before the three listeria cases that were reported last week, but has only just been discovered to be linked to the same strain of the bacteria.
Listeria infection is rare and usually causes a mild illness in healthy people.
Public Health England (PHE) has said the risk to the public is low, and it is continuing its investigation.
In a statement on Friday, PHE said: "Since the multi-agency investigation began into listeria cases linked to sandwiches and salads, Public Health England (PHE) has been analysing previously known cases of listeria from the past two months to see if they are linked to this outbreak.
"Whilst any risk to the public remains low, PHE's Whole Genome Sequencing analysis has identified an additional three cases of listeria linked to this outbreak.
"This brings the total number of confirmed cases to nine. All of the cases of listeria infection were in hospital patients in England.
"Sadly, one of the seriously ill six patients PHE confirmed last week has since died.
"One of the patients confirmed today as linked to the outbreak had already died. This brings the number of deaths linked to this outbreak to five."
The supplier of the infected products, The Good Food Chain, meat producer North Country Cooked Meats and distributor North Country Quality Foods have voluntarily ceased production during the investigation.
In a statement, the Good Food Chain said: "Our thoughts and deepest sympathies are with the families of those who have died and anyone else who has been affected by this outbreak."
It added the underlying cause of the outbreak remains unclear and it is full cooperating with investigations.
Public Health England added: "The affected sandwiches and salads were withdrawn from hospitals when the links to the listeria infections were first identified and the multi-agency team then advised NHS organisations not to provide any Good Food Chain products to vulnerable patients.
"Evidence suggests that all individuals ate the affected products before the withdrawal took place in hospitals on the 25 May 2019. The food chain investigations continue."
Dr Nick Phin, deputy director at the national infection service at PHE, said: "To date, there have been no patients linked to this incident outside healthcare organisations, but we continue to investigate.
"Swift action was taken to protect patients and any risk to the public is low. 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."