Researchers have been unable to find the original source in a Welsh Shigella outbreak that affected more than 50 people.
In February 2023, 52 cases of gastrointestinal illness were reported in customers of a takeaway in South Wales. Shigella flexneri serotype 2a was the causative organism.
In December 2024, operators of Marmaris Kebab House, Sami Abdullah and Hassan Saritag, admitted food hygiene offences at Newport Magistrates Court and were fined in relation to the incident.
Thirty-one patients and 29 controls were included in a study. Eighty-seven percent of patients and 76 percent of controls ate from the takeaway on Feb. 10, 2023. Coleslaw was the main factor associated with illness and a link with cabbage was identified. Shigella was not detected in staff samples. Stool samples provided by six close contacts of staff were also negative.
Food handler’s role
According to a study published in the journal Epidemiology and Infection, coleslaw was the most likely vehicle. Though the contamination route remains unknown, a food handler was the most likely source, according to the research report.
On Feb. 17, 2023, Public Health Wales (PHW) was contacted by a microbiology laboratory following nine reports of presumptive Shigella in fecal samples. Cases lived in two neighboring places in South-East Wales. Four people had been hospitalized as a result of their symptoms. Environmental Health Officers (EHOs) found all nine patients had eaten at the same takeaway on Feb. 10 or 11, 2023, with symptom onset reported between Feb. 12 and 13.
Thirty of the 52 cases were women and 11 people were hospitalized. The median age of patients was 41 but ranged from 1 to 75 years old.
Two patients did not eat at the takeaway. These people are thought to have been exposed to Shigella via direct contact with those who had eaten food from the restaurant.
An inspection of the takeaway identified missed opportunities for handwashing and equipment cleaning between handling raw and ready-to-eat foods, including dirty and washed vegetables. Temperature control in the display fridge exceeded UK standards of 8 degrees C (46.4 degrees F). This was previously noted during a routine inspection in May 2022.
The business voluntarily closed from Feb. 12 to 16, 2023, for planned refurbishment and cleaning, so it was not possible to sample food preparation services or to collect food samples for testing.
Coleslaw suspected
The case-control study identified coleslaw as the likely vehicle for infection. The high-fat content and large surface area of coleslaw make it an ideal vector for the transmission of foodborne illness. It is unclear how coleslaw became contaminated. Inspection of the takeaway by health officers noted that coleslaw was made fresh onsite daily.
Where customers ate both coleslaw and cabbage, the odds of illness were much greater than eating either item on their own, though the effect of cabbage alone was much smaller than that of eating coleslaw without cabbage. Cross-contamination may have occurred during food preparation, storage, or service.
The investigation used data from an online app as a source of case and control recruitment for the analytical study. Some controls had ordered from the takeaway via an online app. However, by the time data were made available, more than a month had elapsed since the outbreak occurred.
Four Freedom of Information requests were filed with Public Health Wales in relation to the outbreak and, after two refusal notices, a report was published in 2024.
(To sign up for a free subscription to Food Safety News, click here)
