Maggots were found in the milk given to children at a kindergarten in the southern province of Tay Ninh last month.
Dirty milk containers at the school are believed to be the source of the problem.
A mother, only identified as H., told Thanh Nien that she and several mothers discovered the situation on the morning of September 29 when they brought their children to An Co kindergarten and stayed to see how the children were fed.
The children were given hot milk in stainless steel cups, in which H. and other mothers found the maggots.
Tran Thi Mai Chi, the school principal, said the school has looked into the problem and found that milk containers at the school were not cleaned properly.
Milk at the school is made in a big vessel by mixing powdered milk in packages with hot water.
The milk is then poured into stainless steel kettles and into the children's cups, Chi said.
The nursery school currently takes care of 252 children.