Local weather forecasters are to offer a service next year, which will tell people of the risk of bacterial food poisoning based on temperature and humidity conditions.

A red alert will mean a 25-percent or more risk of bacterial food poisoning, a yellow alert means there is a 15 to 24-percent possibility.

There will be no alert if the risk is low. Bacteria is the cause of three quarters of local mass food poisoning cases.

The different alerts will be sent to local food authorities, restaurants, food producers, school cafeterias and residents, along with precautions about how to prepare food, based on weather conditions.

A trial of the scheme will be launched from April to October next year, and the warning will be sent via text message or by e-mail every day.

The service will be incorporated into media weather reports before the 2010 Shanghai World Expo.

The April to October period is the peak season for bacterial food poisoning cases.

A research team of officials from the Shanghai Climate Center under the Shanghai Meteorological Bureau and the Shanghai Food and Drug Inspection Institute said yesterday that bacterial growth is closely related to temperature and humidity, plus the type of food and its acid and alkaline levels.

"Bacteria grow fastest between 20 and 40 degrees Celsius and high humidity is an ideal cradle for bacteria production," said Li Jie of the Shanghai Food and Drug Inspection Institute.

"This is the first time Chinese food-safety and weather authorities have cooperated to forecast bacterial food poisoning," she said.

The research team worked out the alerts by comparing weather conditions with mass food poisoning cases in the city between 1992 and 2006, and improved their accuracy by using the format to check cases in 2007 and 2008.

"Most mass food poisoning cases in 2007 and 2008 took place within three days of red or yellow-alert conditions," said Yuan Zhaohong, vice director of the Shanghai Meteorological Bureau.

On average, there are 19 days with red-alert conditions and 44 to 45 yellow-alert days recorded each year in the city.

(Shanghai Daily December 25, 2008)