LOS ANGELES (AP) — Eva Longoria says she lent her support to “The Harvest,” a documentary about child migrant laborers, not just because of her Latin American roots but also because she wants to know where her food comes from and take responsibility for it.

Much of the harvesting work in the United States is done by migrants from Latin America, especially Mexico. But Longoria’s interest in the subject didn’t spring from her roots, but from concern over children growing up in the fields, the “Desperate Housewives” star says.

“I’m ninth-generation Mexican-American. We have ranches in Texas but you don’t have to have that to have compassion,” Longoria said. “I eat food and I’m a responsible human being and if you are responsible, you have to know where your food comes from.”

Longoria said a quarter of food eaten in the United States is harvested by children. That estimate could not be immediately confirmed by The Associated Press. Human Rights Watch reported in 2010 that at least 10 percent of hired farm laborers in the United States were under 18, but said that accurate numbers were hard to come by.

The documentary says that more than 400,000 children work in U.S. farm fields.