Dozens of kindergarten children reported symptoms of food poisoning after lunch at a school in Fujian province on Wednesday, renewing the debate on food safety on Chinese campuses.
The Fujian outbreak involving 170 children came after an international school in Shanghai was found in October to have stored mouldy vegetables and expired seasonings and led to citywide hygiene checks.
In the latest incident, administrators at Shizhe Kindergarten in Yongchun county, Quanzhou, told the county's education bureau that pupils had become unwell.
Of the 170 who sought medical attention, 10 were kept in hospital overnight for treatment and observation, the bureau said.
A sample taken from a pupil and examined by disease control centre officials was found to contain norovirus, which commonly breaks out in winter months.
Norovirus can be contracted by eating shellfish and salad ingredients that have not been properly prepared or by eating food prepared by an infected person.
It can also be transmitted through the air and infect people close to sources of contamination such as bodily fluids or toilets.
The county education bureau said it was still investigating the case.
"The hospital was full of children. All of them threw up and some had diarrhoea," Li, the father of a four-year-old boy, told the Quanzhou Evening News.
Another parent said her child complained of a stomach ache after school and then started vomiting, according to the report.
"His face turned white, and his lips turned white. I thought it was a flu or intestinal problem, but many parents started saying the same thing later," she was quoted as saying.
According to the head teacher, identified by local media by his surname Chen, the school offered pupils noodles, sausages and dessert for lunch and porridge at 2.30pm on Wednesday. They began to report feeling unwell and vomiting shortly afterwards.
The classes affected were closed and the campus was fully cleaned, Chen said.
News of the outbreak led to angry reaction online.
"Food safety at schools, again?" wrote one Weibo user.
"If our level of control over food, medicine, water, and air can reach half of that over trains, subway and planes, our society will be good enough," another post said.
In June, 103 pupils from a nursery school in the Minhang district of Shanghai contracted norovirus. About 30 children at a kindergarten in Changsha, Hunan province, contracted the virus in November 2017.
Children under five are the most affected by the virus, but patients typically recover within one to three days. Prevention involves proper hand washing and disinfection of contaminated surfaces.
This article was first published on South China Morning Post.