LOS ANGELES – As children return to school, parents again will ask the question they have pondered for ages: What happens to lunch money? Bullies? Pockets with holes? Kids who eat too many Twinkies?

Computer technology might have solved the mystery. A program called MealpayPlus, from Horizon Software International of Duluth, Ga., lets parents track what their kids are buying with their lunch money and see exactly what they're eating. Parents also can control lunch purchases, nixing junk food.

More than 250 school districts use the system, including Dallas, Cedar Hill, McKinney and Birdville, as well as the Los Angeles Unified School District.

"If parents don't understand how their student goes through $30 in three days, they can view their students' current account balance," said Ashley Steele, senior product coordinator for MealpayPlus.

Students pay for their lunches with MealpayPlus in different ways, depending on the school district. Some will get a scan card. Others get a PIN. Some school districts will take images of students' fingerprints, using biometrics to track lunch spending.

Busy parents can go online and add money to their children's accounts. They also can flag foods to which their kids are allergic and elect whether their child can buy meals only or also snacks.

The Hacienda La Puente district in California's San Gabriel Valley has used the service for a few years. Geri Dee, director of food services, said it allows parents to make sure their kids are eating healthfully.

The service also makes buying lunch less embarrassing for students getting reduced-price meals, said Vera Iosua, a Hacienda La Puente office manager.

In 2007, she signed up her children, Chelsea, 16, and Howard, now 18, for MealpayPlus. Her kids only had to enter their PINs to pay for lunch rather than fork over cash, which meant it was harder for others to tell that they were paying less for meals.

She saw from computer tracking that her son ate a lot of pizza but, she was relieved to know, sometimes had a salad.