In the United States, harvesting work tends to be done by migrants of Latin American origin, but Longoria's interest in the subject didn't spring from that, but from the children who are 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."
Twenty-five percent of the food we eat in the United States is harvested by children, Longoria said in a phone interview from the set of "Desperate Housewives," now shooting its final season. Every year, more than 400,000 children work in U.S. fields, according to the documentary.
"You have to be aware of the practices that are used to get the food we are eating," said the actress, who as executive producer of "The Harvest," raised nearly $1 million for the film, which will be released on DVD Tuesday.
"I've been involved with farm workers advocacy for a long time," she said, "but I recently found out, I didn't know there were so many children working legally in the fields."
"The Harvest" tells the story of three children who work as field laborers in Florida, Michigan and Texas to help their parents.
In the film, one of them, 12-year-old Zulema Lopez, notes that she started working at such a young age, she doesn't even remember her first day. She adds that picking onions in Texas from 5 a.m. to 5 p.m., she made $64 a week.
The child field workers work under an unforgiving sun and in paralyzing cold and run the same risks and suffer the same deprivations as adult laborers, the film shows. Lopez, for example, recounts how she had to throw dirt on a wound to stop it from bleeding. The film also explains how migratory work makes it difficult for children to receive a proper education.
The film has been shown to members of Congress to put a face on a bill sponsored by Rep. Lucille Roybal-Allard, D-Calif., that would raise the minimum age for field work in the U.S. from 12 to 14 years. It also seeks to create penalties for labor infractions against young field workers and reduce their exposure to pesticides.
"We want to use the film to change policy," Longoria said. "Children shouldn't have to choose between school and work."
Longoria says the most touching scene of the film for her is one in which Lopez fears she'll have to work in the fields her entire life, remarking, "I don't even think about having dreams."
"That was heartbreaking," Longoria said. "Her grandmother works in the fields, her mother works in the fields, and she feels stuck and does not see herself leaving the fields."