Chopped parsley may have been the cause of Northern Ireland's worst E.coli outbreak.
More than 140 people fell ill after eating at Flicks Restaurant in Belfast during a three-month period in 2012.
An investigation by the Public Health Agency (PHA) found chopped parsley, used to garnish dishes, had not been adequately washed or refrigerated to kill bacteria.
The news comes after the owners of the restaurant were fined £110,000 after admitting a series of hygiene breaches.
During the outbreak 141 cases were clinically confirmed with 19 people admitted to hospital and a further 159 presented symptoms.
The PHA said poor practices within the restaurant contributed to the spread of the bacteria and that some meals may have been garnished by a food handler who had contracted E.coli. Staff toilet facilities were found to be inadequate with no soap or drying facilities.
The restaurant closed voluntarily on 11th October 2012, following advice from the Belfast City Council's environmental health staff. It will not reopen.
Flicks owner Michael McAdam told the BBC he was "devastated" that people had become sick. He said: "I am personally devastated that any business of mine could have caused people to become ill. "I would just like to take this opportunity, once again, to say how deeply sorry I am to anyone who fell ill as a result of eating at Flicks restaurant." The restaurant is not expected to re-open.