Jason Olsen, a Salt Lake City District spokesman, said the district's child-nutrition department became aware that Uintah had a large number of students who owed money for lunches.
As a result, the child-nutrition manager visited the school and decided to withhold lunches to deal with the issue, he said.
But cafeteria workers weren't able to see which children owed money until they had already received lunches, Olsen explained.
The workers then took those lunches from the students and threw them away, he said, because once food is served to one student it can't be served to another.
Children whose lunches were taken were given milk and fruit instead.
Olsen said school officials told the district that their staffers typically tell students about any balances as they go through the lunch line and send home notifications to parents each week.
The district attempted to contact parents with balances via phone Monday and Tuesday, Olsen said, but weren't able to reach them all before the child-nutrition manager decided to take away the students' lunches.
"Something's not working, and that's what the school and child-nutrition department are going to work on together," Olsen said of the notifications.
He said there's no plan to use the same tactic at other district schools.
"This can be easily prevented," Olsen said. "We need to make sure proper notification goes out to the parents and they have time to put money in the accounts."
But Olsen said he would not describe the tactic as a mistake.
"If students were humiliated and upset," Olsen said, "that's very unfortunate and not what we wanted to happen."
However, after further investigation, Olsen released an updated statement that was also posted to the district's Facebook page. It said: "This situation could have and should have been handled in a different manner. We apologize."
The post adds: "We understand the feelings of upset parents and students who say this was an embarrassing and humiliating situation. We again apologize and commit to working with parents in rectifying this situation and to ensuring students are never treated in this manner again."
Olsen said it's standard in the district to give kids fruit and milk in lieu of lunch if they don't have the money to pay for lunch.
He said it's unclear how Uintah had been handling such situations before this week. Attempts to reach Uintah's principal were unsuccessful.
Olsen said the district encourages parents to use its electronic system to pay for lunches and set up email notifications. He said the software for the system is new this year, though it's not much different than the old one.
Lukes said she never received a notification that her daughter would have her lunch taken.
She said it was a difficult day for her daughter and other kids. She said her daughter told her one of the cafeteria workers cried at the sight. And her daughter's best friend was so upset that she went home Tuesday night and made lunches for all the students who had theirs taken, she said.
"You would think in a public school system your child wouldn't be turned away from lunch," Lukes said, "especially when people usually settle their balances."