Public health authorities adopted a hit-and-miss approach to dealing with E.coli in Northern Ireland, a politician has claimed.
An outbreak linked to a Belfast restaurant is the most significant seen in the province, a Department of Health official said.
Twenty-five confirmed and 154 probable cases of food poisoning were detected following an investigation at Flicks restaurant in north Belfast, the Public Health Agency confirmed.
Eight people were taken to hospital with one adult still an inpatient. Several children under the age of 14 are suspected to have contracted the illness, according to the department.
This is the second cluster of cases of E.coli linked to Flicks in recent months and Sinn Fein MLA Sue Ramsey asked whether action could have been taken sooner.
She said: "It is a lesson that people need to learn from this, that we do not have this hit-and-miss approach, that whenever this is serious that we look at it as a serious issue."
Stormont's health committee is investigating the matter.
The same restaurant was investigated after an August outbreak of the illness affected four people at the York Street eaterie. At the time, the Public Health Agency and Belfast City Council environmental health officers carried out an investigation and all tests on the restaurant were negative.
It was shut down voluntarily by its owner, Michael McAdam, after the latest cases were detected earlier this month. He said hygiene in the kitchen met the highest standards.
Dr Elizabeth Mitchell, deputy chief medical officer, told the health committee enhanced monitoring had been put in place.