Two more hospitals have been named as having had listeria-related patient deaths occur on their premises after pre-packaged sandwiches and salads were consumed - bringing the total deaths to five.
The locations are University Hospitals of Derby and Burton NHS Foundation Trust and University Hospital of Leicester NHS Trust, Public Health England said.
It comes after an outbreak of listeria was confirmed following the deaths of three patients who had eaten a particular brand of sandwiches and salads, which have now been withdrawn from hospitals.
The first three victims to die were at Manchester University NHS Foundation Trust and Aintree University Hospital NHS Foundation Trust in Liverpool.
Three other hospitals have diagnosed cases of listeria linked to the outbreak but with no associated deaths.
Those sites have been confirmed by Public Health England as being: Western Sussex Hospitals NHS Foundation Trust, Frimley Health NHS Foundation Trust, East Kent Hospitals University NHS Foundation Trust.
All affected patients ate products believed to be involved in the outbreak before 25 May.
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.
The supplier of the infected products, The Good Food Chain, meat producer North Country Cooked Meats and distributor North Country Quality Foods have all 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.
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.
It comes as Health Secretary Matt Hancock promised "severe consequences" if there is evidence of "wrongdoing" following an outbreak of listeria.
Speaking in the Commons, Mr Hancock said: "The NHS has identified nine confirmed cases of listeria in seven different hospitals between April 14 and May 28, all linked to contaminated sandwiches from a single supplier.
"All the cases involved inpatients and, very sadly, five people have died."
Mr Hancock expressed condolences to the families who have lost loved ones and promised a root-and-branch review of food sold and served in hospitals.
He added: "I promise there will be a full and thorough investigation, and severe consequences if there is any evidence of wrongdoing."