The school board, Conseil scolaire de district catholique Centre-Sud, said in a statement Thursday that the teacher's actions reflected poor judgement.
Although the teacher has apologized, the French Catholic school board says her behaviour was unacceptable and does not meet the board's standard of professional ethics.
The board says it regrets the incident at a Simcoe, Ont., school took place and offered "sincere apologies" to the eight-year-old student and her family.
The girl's mother says the teacher took the banana from the garbage, peeled it with her bare hands, broke off a piece, ate it, then instructed the girl to eat the rest.
She says her daughter said it was black all over but she ate around the black spots.