Vu Manh Duong, Director of Ninh Binh province’s Health Department, said that tests done on food samples showed the presence of yellow staphylococcus bacteria in the lunch served to pupils at the Dinh Tien Hoang Primary School on Friday.
A quarter of the school’s 1,300 pupils were hospitalized and diagnosed with food poisoning.
Duong said that the bacteria was found in the salted shredded chicken dish, which was part of the lunch, alongside rice, fried shrimp and tomato soup.
The bacterial would have come from stale meat, improperly preserved meat, undercooked meat or unclean cooking, he added.
As soon as the cause was identified, local authorities sealed the store that supplied the shredded chicken and destroyed the remaining stock, Duong said.
The school’s caterer has also been suspended, he added.
Among the students hospitalized, one currently has tonsillitis and two others have mild fever, Duong said, adding that none of them have nausea or stomachache.
Around 953 pupils had the school lunch, served for VND15,000 ($0.65), on Friday.
The school principal Do Van Tu said the same day that all food sources were carefully chosen from reliable suppliers to ensure safety and hygiene.
Mass food poisoning occurs several times every year in Vietnam, and most of the victims are eating from school and factory canteens.
In December last year, 142 pupils at An Phu Primary School in HCMC’s District 2 were hospitalized and diagnosed with gastrointestinal infections. They too, had consumed food served at the school.
The offenders in such incidents are rarely taken to court.
Official government data shows 53 food poisoning cases affected 1,300 people and killed 11 in the first half of this year.