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.
The hospital effectively turned my wife away when there could have been more of a chance of saving her life.
It was disgusting the way she was dealt with.
We were about to celebrate our 25th wedding anniversary.
Della was so fit and healthy, I can’t believe it. This is devastating.
Dr Mike Gill, Medical Director at Queen's Hospital, said:
A patient attended our Emergency Department on Boxing Day with what appeared to be food poisoning. The patient was seen and fully assessed by a senior clinician, and given appropriate treatment and advice before returning home.
The Trust followed accepted medical practice. We will be fully reviewing the case. We have written to the family offering our condolences at this very difficult time and inviting them to meet with medical staff who can answer any queries or concerns they may have.
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 local authority is investigating an alleged food poisoning outbreak at the Railway.
We are fully co-operating.
Until the investigation is complete we can’t speculate about a possible cause or source.
– Havering Council spokesperson
We are very sorry that to hear of this sad death and our thoughts are with the family at this time.
Havering Council is currently investigating a food poisoning outbreak along with the HPA.
Our initial findings indicate that this seems to be a serious but isolated incident and the venue is cooperating fully with the investigation.
Our officers conducted a second site visit yesterday to gather further evidence and statements from employees.
Our thoughts are with the family at this sad time. We have been working with Environmental Health Officers at Havering Council to identify the cause of illness and any links to food eaten at the venue.
The venue has been cooperating fully with our investigations.
Clostridium perfringens bacteria are the third most common cause of food poisoning in the UK and this mostly occurs in relation to red meat or poultry.
Indications suggest that this outbreak is an isolated event.
People become unwell on average after about 12 hours of eating food contaminated with Clostridium perfringens, with diarrhoea and abdominal pain being the main symptoms.
The illness generally lasts no more than a few days although vulnerable groups such as very young children, elderly people, and those with underlying health problems can be more seriously affected.
It is rare for a person to die as a direct result of food poisoning.
– Dr Deborah Turbitt, director of the Health Protection Agency’s local Health Protection Unit
People who become unwell with symptoms of food poisoning are advised to drink plenty of fluids and take rest at home.
If symptoms are particularly severe or do not settle within two days then they should seek medical advice.
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.