Parents in Utah are upset this week after school officials took lunches away from children and threw the food in the trash because their cafeteria accounts had run out of money.

The incident occurred Tuesday in the Uintah Elementary School in Salt Lake City and the Associated Press said the meals were taken away from as many as 40 students.

An official with the Salt Lake City School District's nutrition department told ABCNews.com they had to throw the students' food away due to safety and sanitation reasons. Specifically, once a lunch is served to one student it can't be given to a different child.

"Unfortunately, children are served lunch before they get to the computer for payment. The children who didn't have enough money in their accounts had their normal food trays taken from them and were given the fruit and milk," the district said in a statement on Facebook Wednesday night.

The district said in a statement that school officials called parents on Monday and Tuesday to inform them of their lack of funds, but parents have reported being surprised after learning of the negative balance on their accounts.

The statement expressed remorse for the incident and said the district is investigating the actions taken by school officials.

"Our jobs are to take care of our kids, not take their food away," said Salt Lake City School District Nutrition Supervisor Laura Larsen.

Diane Pratt-Heavner, spokesperson with the School Nutrition Association, told ABCNews.com that the incident points to a lack of regulation when it comes to school lunches.

"The USDA provides no guidance on children showing up without lunch money, which puts the school between a rock and a hard place," Pratt-Heavner said.

Her organization is calling on Congress to make the USDA inform schools of what "best practices" are applicable when dealing with students without lunch money. They say individual schools currently determine if students will receive meals without payment, which is a problem across the country.