15 August 2014, 17:13 | Updated: 15 August 2014, 17:21
Health officials are investigating a national outbreak of salmonella that's left more than 150 people ill, including 25 in London.
Public Health England (PHE) say they are looking into an outbreak of Salmonella Enteritidis which has affected 156 people across London, Hampshire, the West Midlands and Cheshire and Merseyside.
Salmonella is one of a number of bacteria that can cause food poisoning.
The cases occurred in "isolated clusters" over several months but officials now say they could be potentially linked.
Genetic tests suggest that the cause of illness in the 156 people could have come from a single source, PHE said.
PHE investigators are working alongside the Food Standards Agency to look into the cause of the outbreak - which may have also affected people in France and Austria.
Dr Paul Cleary, a consultant epidemiologist leading the PHE investigation, said: "We are working with our colleagues across PHE, at the Food Standards Agency, in local authorities and with other public health organisations in Europe to investigate the cause of this outbreak. We are making good progress and hope to have more conclusive evidence shortly.
"We will continue to monitor the situation and if there is any further public health action necessary then we will ensure that this takes place."
Across England experts are examining 55 cases in Hampshire, 32 of which have been connected with an oriental restaurant, and 33 cases in Cheshire and Merseyside, 31 of which have been linked to one oriental takeaway.
PHE are also looking at 43 cases in the West Midlands, 34 of which were connected with the Birmingham Heartlands Hospital outbreak.
Salmonella Enteritidis is a strain of bacteria that causes gastrointestinal illness and is often linked to poultry or eggs.
Professor Anthony Hilton, head of biological and biomedical science at Aston University, said: "If the cases are related, the next important stage will be identifying common risk factors which are associated with the infected individuals. This might be consumption of a contaminated food or ingredient or even a common exposure at an event or activity.
"Compiling food and exposure histories of cases occurring over several months can be complex and time-consuming, depending on the quality of the information available, and it may be some time before we know the true extent of the outbreak and the causative link, if any."