Rancid noodles were to blame for last week's nitrite food poisoning incident at a primary school in Haikou, Hainan Province, a local official said yesterday.

One pupil is still in hospital but all the other 28 who were admitted with food poisoning have been discharged, Huang Xingguang, mayor of Haikou, said at a press conference.

The children, aged from six to 10, are from Changmao Primary School in Haikou. They fell sick at about 2 PM on February 16 after having had noodles for lunch at the school canteen.

About 600 children had lunch at the canteen. Many later complained of stomach pains, and suffered symptoms of vomiting, abdominal distension, and dizziness. A total of 35 pupils were sent to hospital for suspected food poisoning.

Tests showed that the children were suffering from nitrite poisoning. Nitrite is commonly found in pickled foods. However, the school canteen workers denied that they had provided pickled food for lunch.

Further investigations showed that canteen workers had used noodles left over from breakfast. The noodles were already rancid by lunchtime, according to Huang.

The local education authorities have issued a warning to the primary school and have handed out punishments to those responsible for the incident, Huang said.

(Xinhua News Agency February 24, 2006)