An 82-year-old “active” Jewish grandmother from Manchester died of natural causes, a jury ruled this week, and a kosher caterer at her great niece’s wedding was not to blame.

The inquest opened on Monday with an emotional plea from her son to question “sub-optimal” hospital treatment she allegedly received.

René Kwartz died at North Manchester General Hospital in August 2010 from pneumonia, contributed to by salmonella enteritis. It was suspected she fell victim to an outbreak of salmonella which struck her great-niece’s wedding in Prestwich, after which dozens of people reported stomach illness.

Investigations by the Health Protection Agency concluded earlier this year that the outbreak was most likely caused by infected beansprouts served at the wedding, although no conclusive link was made with the celebration’s kosher caterer, Shefa Mehadrin.

Mrs Kwartz had developed pneumonia in hospital after she was admitted suffering from a salmonella infection which also affected guests at the wedding the inquest concluded. Mrs Kwartz had developed salmonella nearly two weeks after the wedding.

The inquest heard from a large number of witnesses over three days, including chefs from Shefa Mehadrin, who said they had food safety qualifications but had not received formal training during their employment by the caterer.

The HPA’s investigating doctor and senior doctors from North Manchester General Hospital also gave extensive evidence.

The Manchester coroner ruled that kosher caterer Shefa Mehadrin was not "causative" in the death of Mrs Kwartz. He ruled that the evidence could not support a legal definition of neglect on behalf of the caterer. The same ruling against a conclusion of neglect was also recorded for North Manchester general hospital, after questions were raised over its care.

Mrs Kwartz’s son Jeffrey, a former consultant doctor at the hospital, told the jury he had concerns that his mother was put in a side ward. “I’m convinced that if she had been given antibiotics she might have not gone downhill,” he said, alleging that doctors had given “sub-optimal treatment of an elderly lady, who was not just an elderly lady, she was my mother.”