Boiled salmon linked to five food poisoning outbreaks
What it found
Five large outbreaks of food poisoning in people were linked to boiled salmon served cold.
The bacterium Clostridium perfringens was found in the fish and in sick people.
What they found
Studies in people
Outbreaks and symptoms
Five outbreaks of food poisoning were linked to boiled salmon served cold. People had severe diarrhoea, stomach cramps and nausea, usually starting 6 to 30 hours after the meal.
Largest outbreaks
In the two largest outbreaks, about 500 people were affected in one and 284 of 371 people who replied to a questionnaire were affected in the other. The salmon was the food most strongly linked to illness.
Studies in people and animals
Bacteria in food and people
Clostridium perfringens was found in the salmon and in stool samples from sick people. In some outbreaks the bacteria from the fish and from patients were the same serotype.
Other findings
Cooling and storage
In all outbreaks the fish had been boiled then cooled or stored for a long time before being eaten. The authors think the bacteria multiplied during this time.
Preparation advice
The authors recommend dividing large salmon before or soon after boiling, removing fish from the cooking liquid to cool for no more than one and a half hours, and chilling quickly in thin layers.
What the authors conclude
- They conclude that the illness in all five incidents was caused by Clostridium perfringens and that salmon was the food in which it multiplied.
- They recommend that large whole salmon be divided before or soon after boiling to speed cooling.
- They advise removing fish from the liquor after boiling and cooling it covered but not wrapped for no more than one and a half hours.
How it was done
Food poisoning from Clostridium perfringens is usually linked to meat or poultry. The authors wanted to describe five outbreaks where boiled salmon served cold was the likely cause.
They investigated five outbreaks of food poisoning between 1974 and 1985 in England. They examined food, stool samples and questionnaires from people who became ill after eating boiled salmon.
What it can’t tell you
- This paper describes outbreaks and investigations. It cannot prove that every case was caused by the salmon, especially where food samples were not available.
- The authors relied on people's memories of what they ate and how the food was prepared, which may not be completely accurate.
The paper
- Title
- Large outbreaks of Clostridium perfringens food poisoning associated with the consumption of boiled salmon
- Type
- Study
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Hewitt JH, Begg N, Hewish J, Rawaf S, Stringer M, Theodore-Gandi B (1986). Large outbreaks of Clostridium perfringens food poisoning associated with the consumption of boiled salmon. The Journal of hygiene. doi:10.1017/s0022172400064366Free full textPubMed 2874173DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error