A review of National Health Service food has been ordered by Conservative Health Secretary Matt Hancock after the number of deaths linked to a Listeria outbreak from pre-packed sandwiches and salads rose to five and the case count to nine.

“I have been incredibly concerned by this issue and strongly believe that we need a radical new approach to the food that is served in our NHS. Staff, patients and families deserve so much better – our NHS should be at the forefront of supporting people to make healthy choices,” said Britain’s Hancock.

PHE figures show five confirmed Listeria patients in the week ending June 16, compared to seven, six and four in the three previous weeks. The prior three weeks all reported two infections.

Sandwiches and salads linked to the outbreak have been withdrawn and the supplier, The Good Food Chain, has voluntarily ceased production. A company statement said it was co-operating with the Food Standards Agency and other authorities.

“The underlying cause of it remains unclear. We understand that the investigations being carried out are complicated and will involve a number of stakeholders, but we hope the authorities will pursue their inquiries with all urgency so the wider industry can learn any lessons as soon as possible, and so those affected do not have to wait too long for answers,” according to the Good Food Chain statement.

Two patients at Manchester University NHS Foundation Trust and one each from Aintree University Hospital, University Hospitals of Derby and Burton and University Hospitals of Leicester have died.

Public health experts advised the East Kent Hospitals University NHS Foundation Trust of a potential problem with sandwiches containing chicken on May 26. A patient in one of the trust’s hospitals was affected and then treated. Frimley Health and Western Sussex hospitals NHS Foundation Trust also reported cases.

Jonathan Ashworth, Labour’s shadow health and social care secretary, said there needs to be a review of hospital food and adoption of minimum standards.

“These sandwiches were distributed across a number of trusts which is why last week I called on ministers to updat Members of Parliament urgently on action taken to date. Patients and NHS staff will expect reassurance and ministers must outline what checking procedures on batches are in place now and for the future,” he said.