A woman has died and 30 people have fallen ill following a Christmas Day lunch at an east London pub.
BBC News reports Della Callagher died two days after eating at the Railway Hotel in Hornchurch.
The Health Protection Agency (HPA) began an inquiry after the Clostridium perfringens bacterium was found in samples from the affected diners.
Mrs Callagher’s husband John said he took her to hospital on Boxing Day but is angry doctors told her to go home.
He said she got worse the next day and was taken to hospital where she died.
“If she was rolling around on the floor they would have admitted her – but because she was dignified she wasn’t,” he said.
The couple, who live in Hornchurch, have a 14-year-old daughter and Mrs Callagher’s funeral takes place on Saturday.
Dr Mike Gill, medical director for Barking, Havering and Redbridge University Hospitals NHS Trust, said the patient was given appropriate treatment and advice.
“The trust followed accepted medical practice,” he said. “We will be fully reviewing the case.
A spokeswoman for The Railway Hotel, which remains open, offered condolences to the family.
She added: “We are fully co-operating with the environmental health and Health Protection Agency teams while they conduct a thorough investigation.
“However until this investigation is complete we can’t speculate about the possible cause or source.”
A Havering Council spokesman said: “Our initial findings indicate that this seems to be a serious but isolated incident.