As many as 10,000 German school children stricken since Friday  by a vomiting virus may be suffering from eating cafeteria food, health authorities say.

While the investigation is far form over, attention has focused on the food services company called Sodeco that supplies cafeteria food to many schools and day care centers in areas of German experiencing the outbreak.

Berlin health officials expect most children will recover from the norovirus symptoms within a few days, but in the meantime the young people are suffering from vomiting, diarrhea, nausea, stomach pain, fever, and head and body aches.

Laboratory testing is currently underway to determine the cause of the massive outbreak of illnesses.   The prestigious Robert Koch Institute has told the media that a single food supplier did serve all the schools and day care facilities reporting illnesses.

Until the source of the virus is found and the outbreak is over, German school and pre-school children are being encouraged to pack their own lunches.

Children who are ill are being told to remain hydrated and to avoid sugary beverages because such drinks can make the symptoms of diarrhea worse.

A task force of state and national officials was set up on Friday to investigate the cause of the illnesses, as the number of sick German school children grew rapidly.

The Robert-Koch Institute told the newspaper Die Welt that the ill children attend schools and pre-schools in  Berlin, Brandenburg, Saxony and Thuringia.

Consumer Affairs Minister Ilse Aigner said the goal was “to find the cause of the illnesses as soon as possible and to stop its entry into the food chain.”

A spokesman for Sodexo said less than five percent of the schools it serves has sick children.   He said the cause of the illnesses may be a norovirus that is not food related.

“The reason that almost all of the children ate food from our kitchens is simply because we deliver food to a lot of schools. We hope that the children feel better soon,” he said.

However, the Robert-Koch-Institute  told Die Welt that it stood to reason that the children were suffering from a food-borne illness, and that some of them had tested positive for the norovirus.

The norovirus, which causes vomiting and diarrhea , is highly contagious, and can be transmitted by contaminated food or water, infected people, or contaminated surfaces.

Some German schools have closed as a precautionary measure.