Public Health England is investingating into an outbreak of E.coli O157 linked to prepackaged salad that has sickened 38 people.
Though whole genome sequencing, Verocytotoxigenic E. coli (VTEC) were first identified in early August 2015.
While 38 cases have been confirmed, PHE added that there is one probable case and four possible cases awaiting results.
Majority of the cases have been reported from Anglia, Cheshire, and Merseyside, while most of the patients are females aged between 18 and 73 years.
A review of VTEC questionnaires has indicated that 33 victims had consumed prepackaged salad and 19 of them had bought the product from at the same supermarket chain.
Investigations are underway to ascertain the source and exact cause of contamination. Analysis of the enhanced VTEC questionnairs found that of the 38 cases, 33 confirmed to have eaten the pre-packed salad and 19 of them had purchased the salad at the same supermarket chain.
The food safety watchdog has initiated traceback, and one distributor who has been supplied by three farms has been identified, reported Food Safety News.
Samples are being collected from supermarket chain outlets, from the distributors and supply farms.