Two women died after eating chicken mayonnaise sandwiches suspected of containing listeria at Manchester Royal Infirmary, an inquest heard.

The findings follow a five-day joint inquest at Manchester Coroner’s Court.

Retired Jamaican nurse Beverley Sowah, 57, and mother-of-five Enid Heap, 84, were given them on successive days while patients at Manchester Royal Infirmary in 2019.

The women died a few days later and the “primary hypothesis” suggests that they suffered listeria infections from the sandwiches the hospital provided – they also had underlying health issues, a joint inquest heard at Manchester Court Coroner’s Court.

Their deaths were among seven fatalities, part of a nationwide alert over the listeria outbreak which affected nine people in all in other hospitals, including in Liverpool, Leicester and Derby.

Tina Potter, head of incident at the Food Standards Agency regulator, told the inquest the outbreak was escalated to a high-priority incident.

The jury concluded the bacteria entered the food chain at cooked meat processing firm North Country Quality Foods (NCQF) in Salford, Greater Manchester.

They supplied the contaminated chicken to sandwich-making firm the Good Food Chain (GFC), based in Stone, Staffordshire, which used it to produce chicken mayonnaise sandwiches.

These were then supplied to Sodexo, who were contracted to supply the NHS trust running the hospital, and the sandwiches were fed to Mrs Sowah and Mrs Heap.

Ms Potter said the investigations suggested the source of the listeria originated in the cooked chicken supplied to the GFC by NCQF, located in Salford.

Safe levels of listeria exist and it is a widespread common bacteria with various strains. The maximum legal limit is 100 colony-forming units per gram (cfu/g), the inquest heard. 

A sealed bag of chicken products was tested a month after the women’s death by public health officials, with the sample showing an “unprecedented high level” of a listeria strain, Ms Potter said. 

The level found in the diced chicken bag was 1,000 cfu/g – 10 times the legal limit.

The two MRI deaths were immediately linked as both patients ate the same sandwiches at the same hospital. They worked backwards to trace the sandwich supplier and which firm had supplied the meat.

Zak Golombeck, Manchester city coroner, said: “You were able to conclude that the source of the listeria contamination was the cooked chicken?”

Ms Potter said: “That’s correct. We drew that conclusion because that was the product that patients had consumed.”

Another customer had a supply of bacon from NQCF which was found to have the strain of listeria involved in the hospital deaths.

Ms Potter added: “So having a pathogen genetically related in two food products within the same business would lead us to a likely hypothesis that there’s an environmental contamination that’s persisted.

“It’s really difficult once it takes a foothold in a business to get rid of it.”

Both women acquired listeria from the contaminated food which more than minimally contributed to their deaths, jurors found.

Both meat supplier and sandwich maker firms have since gone into liquidation.