Rene Kwartz, 82, was one of four guests who needed hospital treatment after a meal at a hotel in Prestwich, Greater Manchester.
Tests later confirmed that nine people who attended the traditional Jewish celebration at the Hilton Suite last month had been infected.
Three of those taken to hospital recovered and were discharged but Mrs Kwartz died last week.
Lawyers representing the guests at the wedding of Stephen Wicks and Jennifer Harris on August 8 are taking legal action against the outside caterers to the function.
Environmental health officers from Bury Council and specialists from the Health Protection Agency’s Greater Manchester Health Protection Unit (HPU) and NHS Bury are investigating the outbreak.
Dr Marko Petrovic, from the HPA’s Greater Manchester HPU, said: “It’s very sad that a patient associated with this outbreak has died and our thoughts and sympathies are with the family. We are looking into the circumstances of the case. Deaths from salmonella infection are rare.”
The external caterers were co-operating fully with the investigation into the outbreak, the HPA said.
Dr Peter Elton, director of public health for NHS Bury, said: “Illness arising from the salmonella bug can be debilitating, especially for young children and older people.
“It is important for anyone with symptoms of salmonella infection, which may include diarrhoea, abdominal pain, headache, nausea, vomiting, or fever, to maintain their fluid levels and take the utmost care with hand-washing and hygiene generally.”