Della Callagher, 46, felt ill after the meal at the Railway Hotel and was taken to the Queen's Hospital in Romford, her husband John told the Evening Standard.
Dr Mike Gill, Medical Director at Queen's Hospital, said:
Ember Inns, which owns the Railway Hotel in Hornchurch in Essex, has said its food was prepared to the highest hygiene standards.
A spokesman told the London Evening Standard:
The Health Protection Agency (HPA) has been notified of an outbreak of food poisoning linked to an establishment in Havering. One person has died after being admitted to hospital.
Around 30 people have reported symptoms of gastrointestinal illness after eating at the venue on Christmas Day.
Laboratory testing has confirmed the presence of Clostridium perfringens bacteria in a number of samples submitted by those experiencing symptoms, including the patient who died.
An investigation is under way into how a woman suffering from rabies was reportedly turned away from a hospital Emergency Department.
The Health Protection Agency has confirmed a case of the potentially fatal disease in a patient bitten by a dog in South Asia.
The woman, believed to be a Grandmother in her 50s, is now being treated at London's Hospital for Tropical Diseases.
In a statement Dartford and Gravesham NHS Trust said:
"If a patient does present at hospital with vague symptoms a doctor is unlikely to consider rabies as a diagnosis unless the patient highlights wild animal contact in an at risk country. The hospital responded to the information supplied by the patient at the time."