The Russian Ministry for Emergency Situations said Monday the remainder of the 259 kindergarten students at the Bratsk, Russia, school were being kept under the supervision of medics in their homes, ITAR-TASS reported.

The consumer rights group Rospotrebnadzor said the illness resulted from tainted rissoles made of rice, eggs and chicken liver served for lunch at the kindergarten.

The mayor of Bratsk declared a state of emergency after the students and staff began to fall ill Wednesday and food items supplied to schools, orphanages and boarding schools in the city were being closely scrutinized.