Almost 1,000 school-children in Japan have become ill in a feared outbreak of food poisoning.

The kids attended nine schools across Hokkaido island in the northern Japan. They started to became sick last week after eating lunch of miso soup, salad and Japanese radish with minced meat.

Thirteen children have been hospitalized in the city of Iwamizawa; while four dozen teachers and other school staff also have symptoms.

According to press reports, the poisoning outbreak spread swiftly Iwamizawa operates large central kitchens which deliver food daily to various schools.

Three of these kitchens have been shut as well while an investigation is carried out.

Local health authorities suspect salmonella may be the cause.