Deep-frozen strawberries are said to be responsible for the recent outbreak of gastroenteritis that hit thousands of people in eastern Germany.

The Robert Koch Institute, Germany’s disease-control centre, has found a strong link between eating food prepared with deep-frozen strawberries and the cases of diarrhea and vomiting.

The gastroenteritis outbreak hit more than eleven thousand people, mostly kids at day-care centres and schools, in the eastern parts of Germany.

Authorities have stressed that food- or water-borne illness pathogen norovirus is most likely the cause of the outbreak, though they didn’t rule out the possibility of other pathogens as the cause of the problem.

However, the authorities also said that the illnesses were moderate and most of the patients recovered quickly without any need to be hospitalized.

Holger Eichele, spokesperson for Agriculture Ministry of the country, said that that the strawberries that triggered the health problem were believed to have been imported from outside the European Union (EU).