Dish behind mass food poisoning of over 100 New Zealand university students identified

The New Zealand Ministry of Health has confirmed that a mass illness outbreak at two University of Canterbury student dormitories in Christchurch was caused by a minced chicken dish. Over 100 students experienced vomiting and diarrhea two weeks ago during the final exam period. The Ministry of Health worked closely with the Ministry for Primary Industries (MPI) to investigate the cause of the outbreak.

Dr. Claire Salter, a public health medicine specialist at the National Public Health Service, stated that after "epidemiological, laboratory, and environmental investigations," the source of the widespread illness was found to be contamination of the chicken dish due to "inappropriate food preparation processes." Laboratory testing of stool samples provided by some of the affected students identified the presence of Clostridium perfringens.

Clostridium perfringens is a bacterium that causes illness by producing toxins. Dr. Salter stated that this illness typically occurs after consuming food that has been kept at unsafe temperatures for too long. Vincent Arbuckle, Deputy Director-General of New Zealand Food Safety, stated that the unsafe handling of meat in terms of cooling, reheating, and hot holding was "consistent with the way the bacterial toxin grows and causes illness." The average time between food consumption and the onset of symptoms was about 11 hours, which Arbuckle stated is typical of this pathogen.

Arbuckle also stated, "If the issue was that the meat wasn't cooked properly, we would expect to see a different pathogen, other symptoms of illness and a different incubation period, usually around two to five days." He said that students can be assured that food safety officers have "fully checked the kitchen and there are no immediate and ongoing food safety risks at the hall." "If we thought students were at risk, we would take further steps to prevent that. We are continuing to review the kitchen practices and procedures to prevent a reoccurrence."

Students at both the university halls and the Ilam student accommodation reportedly consumed chicken from the same gyros. "Survey responses from students found that consumption of the minced chicken dish was the strongest predictor of illness," said Dr. Salter. The reported symptoms were consistent with those caused by Clostridium perfringens. Dr. Salter stated that it is important to ensure the risks are managed properly to prevent a recurrence, and food safety officers have "fully checked the kitchen and taken corrective actions."

An unnamed student earlier told _Stuff_ that there were long queues outside the bathrooms of one of the halls at 4 am on the day of the outbreak. "Over 200 students were either vomiting or experiencing severe diarrhea in the middle of the night," they said. A video sent by a student showed vomit falling from a dormitory window, reportedly because students could not reach the bathrooms in time. Food safety officers from New Zealand Food Safety arrived on site the day after the initial outbreak. The university has stated that students who were unable to sit their exams due to illness can apply for special consideration or resits.