Dozens of kindergarten pupils are poisoned by their teacher who laced their porridge with a toxic chemical to 'seek revenge on a colleague' 23 pupils suffered from nitrite poisoning after teacher contaminated their food Teacher was trying to seek revenge on a colleague after a dispute, reports say Teacher has been detained by police and 22 of the pupils have been discharged By Kelsey Cheng For Mailonline Published: 17:44 BST, 1 April 2019 | Updated: 17:44 BST, 1 April 2019 Viewcomments Twenty-three kindergarten students have been hospitalised after they were poisoned by their teacher in central China. The teacher, who was trying to seek revenge on a colleague after a dispute, brought nitrites, a chemical additive commonly used as a preservative in cured meats, to the school in Jiaozuo, Henan province and added it to the children's porridge on Wednesday morning, local media reported. The children at Meng Meng kindergarten were taken to hospital with symptoms of vomiting and nausea shortly after their breakfast. Video footage shows nurses and doctors treating the sick children at a local hospital after they were poisoned by their teacher during breakfast in Jiaozuo, Henan province A father, surnamed Li, told reporters that he received a call from the principal that his four-year-old daughter felt sick after breakfast What are nitrites and nitrates? The salts of nitrite and nitrate are commonly used for curing meat and other perishable produce. They are also added to meat to keep it red and give flavour, while nitrates are used to prevent certain cheeses from bloating during fermentation. Nitrate is found naturally in vegetables, with the highest concentrations occurring in leafy vegetables like spinach and lettuce. It can also enter the food chain as an environmental contaminant in water, due to its use in intensive farming methods, livestock production and sewage discharge. Nitrite in food (and nitrate converted to nitrite in the body) may contribute to the formation of a group of compounds known as nitrosamines, some of which are carcinogenic - ie, have the potential to cause cancer. In 2015 the World Health Organisation warned there were significant increases in the risk of bowel cancer from eating processed meats such as bacon that traditionally have nitrites added as they are cured. Source: EFSA The unnamed teacher has been detained by police, according to Beijing News. Video footage shows nurses and doctors treating the sick children at a local hospital. Some of the children were seen lying unconscious in hospital bed and receiving IV drips. A father, surnamed Li, told reporters that he received a call from the principal that his four-year-old daughter felt sick after breakfast. 'When I arrived at the school, my daughter had already passed out. Besides my kid, there are three or four other children all looking sick and very pale,' Mr Li said. Mr Li and several other parents immediately rushed their children to the Jiaozuo No.2 People's Hospital, where they were all diagnosed with nitrite poisoning, according to the report. The children all had their stomachs pumped, Mr Li said. 'My child said the porridge tasted bitter and salty when it was supposed to taste sweet,' another parent said. Jiaozuo city police confirmed to Shangyou News that the teacher was seeking revenge on a colleague and decided to poison the children's food. Most of the children have recovered and have been discharged from hospital, according to Toutiao News. One student in critical condition has been transported to Zhengzhou city for treatment. Most of the children have recovered and have been discharged from hospital, according to Toutiao News. One student in critical condition has been transported to Zhengzhou city The local education bureau has halted operations at the kindergarten and the children have been attending other schools in the neighbourhood Located in the suburbs of Jiaozuo city, Mengmeng kindergarten is privately run with only three classes and just more than 50 children in total. It charges about 300 yuan (£34) per month. The local education bureau has halted operations at the kindergarten and the children have been attending other schools in the neighbourhood. Nitrites are used in the preserving process of meats such as bacon, ham and salami. Misuse or excessive use of any medicine or product containing nitrites, whether unintentionally or intentionally, can lead to poisoning. The current acceptable daily intake for nitrates, according to the EFSA, is 3.7 milligrams per kilogram of body weight per day. Share or comment on this article: All rights reserved for this news site dailymail and under his responsibility