Who is responsible for paying America's farmworkers a fair wage, the farmers that employ them or the corporations who control pricing all the way down to the bottom of the supply chain?

That is the question posed by Food Chains, a documentary about the immigrant farmworkers who toil in America's tomato fields earning slightly more than a penny per pound of fruit picked. The movie, which opens Friday, is in many ways a protest film for executive producers Eva Longoria and Eric Schlosser, the author of "Fast Food Nation." Food Chains is the first feature film for director Sanjay Rawal, who previously ran an agricultural genetics company while working in the nonprofit and government sectors.

Like the 2008 documentary Food Inc., which Schlosser also produced, Food Chains is a movie with a mission: reforming an agricultural system that puts profits over people. The victims, in this case, are the tomato pickers of Immokalee, Florida, many of them undocumented immigrants too scared to fight for a legal wage for fear of being deported.

Rather than appealing to farmers for higher pay, the Coalition of Immokalee Workers (CIW), a small group of tomato pickers past and present, makes its case to the biggest purchaser of tomatoes in Florida, the supermarket Publix, whose purchasing power allows it to dictate the price of the tomatoes it buys. Though an increase of just one cent per pound of fruit picked would double the farmworkers' pay, Publix, an employee-owned company, refuses to even sit down at the table with the CIW and--perhaps unsurprisingly--denies that it controls the price of tomatoes.

"When I think about some of the great problems facing this country, and how difficult to solve they are, this is not one of them," Schlosser says.

The backstory

Part of what makes Food Chains so compelling is the way the film chronicles the history of exploitation in American agriculture. Footage from a 1960 CBS News broadcast entitled "Harvest of Shame," narrated by Edward R. Morrow, helps underscore the way farm labor in the U.S. has long relied on the desperately poor.

Going back decades, the film explains how Chinese, Japanese, Punjabi, Haitian, Jamaican and Mexican immigrants have all, at various times, served as the engine of the U.S. agricultural economy by working for a wage that U.S. workers won't accept.

While U.S. labor laws have improved over the years, farmworker pay, almost unbelievably, has gotten worse. When factoring in inflation, tomato pickers today earn about half of what they earned 30 years ago. Due to the rising cost of gasoline and pesticides, growing tomatoes today costs roughly three times what it did in 1960.

As the film explains, corporations have helped pass much of that cost down to the farmworkers. During the 1980s, Walmart essentially upended the agricultural system by selling produce, forcing the rest of the industry to consolidate to stay competitive. During the past three decades, the unprecedented power of supermarkets has drained the revenue from the rest of the supply chain.

"Agriculture is doing great, as long as you're not a farmer," says Barry Estabrook, author of "Tomotoland." 

While Food Chains focuses primarily on the migrant workers of Immokalee's tomato fields, the film also shines a light on similar injustices affecting farmworkers in other part of the U.S., such as California's wine country, where housing is so unaffordable that some vineyards employ workers who are homeless.

Though the farmworkers at the center of the film are predominantly men, many women also work picking fruits and vegetables on America's farms, where an estimated 80 percent are subject to sexual harassment. Worse still are the instances of modern-day slavery depicted in the film, some of which have involved forced servitude of immigrants in Immokalee, where a slavery ring was uncovered in 2010.  

A week without food

In an effort to get Publix to sign the Fair Food Agreement, which requires an extra penny per pound of fresh tomatoes, the CIW organizes a six-day hunger strike. Similar efforts by the coalition, which has held dozens of protests since the mid-1990s, have convinced grocery chains such as Trader Joe's and Whole Foods to sign the agreement, with Publix the last major hold-out among the largest supermarkets.

One of the few uplifting moments during Food Chains comes when Taco Bell joins fast food chains including McDonald's and Burger King and signs the Fair Food Agreement. Publix, however, with annual sales of $27 billion, proves a more difficult opponent for the coalition. 

In a particularly moving scene near the end of the film, Robert F. Kennedy Jr. speaks at the conclusion of the CIW's hunger strike, which took place 44 years to the day Robert F. Kennedy ended a hunger strike with farmworker Cesar Chavez, the founder of the National Farm Workers Association and one of the first organizers to fight for farmworker rights.

"If we cannot win this fight," Kennedy says, "we've lost the soul of America."