One person has died and hundreds more have fallen ill with salmonella food poisoning in a major outbreak which health officials believe is linked to contaminated imported eggs.

The UK Health Security Agency (UKHSA) said the surge in cases was caused by a single strain of the bug. They are investigating the outbreak, which has seen 207 cases detected since the start of the year.

The vast majority of the cases have been in England, with more than a third of those struck down needing hospital care.

Those affected include babies and patients in their 90s, and two have developed life-threatening blood infections.

Salmonella usually causes a fever, nausea, vomiting and diarrhoea which clears up in a few days. But it can be fatal. 

It is typically caught by eating contaminated food such as poultry, meat, eggs, raw fruit and vegetables and unpasteurised dairy products. 

According to the UKHSA, the current outbreak appears to be related to a previous bout of cases in 2025, which was also linked back to contaminated eggs. 

Of the 207 cases confirmed as of August 13, 114 been linked back to five food businesses, with cross-contamination risks identified at two of these premises. 

However, the UKHSA warned: 'At this time there is no identified link to UK-produced eggs or poultry.'  

Health officials are now urging people to take precautionary measures against catching the bacteria, which it said are common causes of food poisoning.

Those in vulnerable groups may develop more severe illness such as bloodstream infections, infection of metastatic sites, sepsis and multiorgan failure, it added. 

Hannah Charles, lead epidemiologist for gastrointestinal infections at the UKHSA, said: 'We’re working with Food Standards Agency and other public health agencies to investigate a salmonella outbreak that may be linked to eggs imported from outside of the UK.

'Salmonellosis is often caused by eating or handling contaminated food and can be spread rarely from person to person. 

'Symptoms - which can take up to 72 hours to develop - include diarrhoea, stomach cramps and sometimes vomiting and fever.

'Anyone who is concerned about symptoms should contact their GP or out-of-hours service in the first instance.

'There are simple steps to prevent the spread of salmonella – wash your hands thoroughly after using the bathroom and before preparing and handling food, cook food thoroughly, and if you have any symptoms, avoid handling food for others where possible.'

Of the 207 cases, 199 are in England, six are in Scotland, one is in Wales and one in Northern Ireland.

In England, London has seen the highest number of cases, with 47 cases confirmed, followed by Yorkshire and Humber where 38 people have fallen ill. 

In response, Dr Damien Tully, Associate Professor at the London School of Hygiene said: 'This is a sizeable outbreak, but the number of confirmed cases is likely to be just the tip of the iceberg. 

'Many Salmonella infections cause relatively short-lived gastrointestinal illness and people may recover without ever being tested, meaning the true number of infections associated with an outbreak can be considerably higher than the number identified through laboratory surveillance.' 

'While Salmonella infections occur every year in the UK, outbreaks linked to a single food source that result in hundreds of illnesses and a reported death are relatively unusual and are understandably a cause for concern,' Dr Aiden Taylor, microbiologist at the University of Reading, said.

'The government's decision to issue a food safety alert reflects the importance of identifying and removing contaminated products from the food chain as quickly as possible.'

There is no reliable way to tell whether an egg is carrying salmonella simply by looking at it, smelling it or checking its shell. 

The safest option is to buy eggs from reputable retailers, keep them according to the instructions on the pack and check the best-before date. 

UK-produced eggs carrying the British Lion stamp or the laid in Britain logo on the shell have additional salmonella controls, including vaccination and testing, and eggs under them are considered very low risk.

If you are unsure of the eggs' origin, cook them thoroughly until both the white and yolk are firm. 

Washing your hands after handling raw eggs and taking care not to let raw egg come into contact with ready-to-eat food can also help minimise the risk of infection. 

Importantly, there is currently no advice to avoid all eggs. UKHSA says the current outbreak may be linked to eggs imported from outside the UK.