"Are you crying?" my 10-year-old son asked, horrified, as we watched the film together for the second time. No, not a film, exactly. More like a commercial. A fast food commercial.

In my defense, a lot of people had an emotional reaction to the two-minute spot for Chipotle Mexican Grill, the Denver-based "fast-casual" burrito chain. The company's first-ever national TV ad aired during Sunday night's Grammy telecast. Produced last year, it's titled "Back to the Start" and features a roly-poly animated farmer who gradually shifts his adorable livestock from their bucolic pasture to a factory farm. Then, dismayed with the results of the industrialized system, he moves them back again. The unmistakable twang of Willie Nelson, singing a craggy cover of Coldplay's "The Scientist," is the only audio accompaniment.

To its immense credit, the film manages to effectively convey the sad lot of industrially raised livestock -- and the persuasive advantages of returning animals to their pastures -- in two wordless minutes. AdAge, the New York Times, and perhaps most surprising, Fox News, all gave the effort raves, for both creativity and underlying message. Obviously, to my son's chagrin, I was sucked in, too. (I blame Willie -- that voice gets me every time.)

This isn't Chipotle's first time at the "let's fix the food system" rodeo. The company has staked much of its identity on its "Food With Integrity" message, describing itself in a recent position paper as "unique in its holistic approach to improving food culture in America." The chain says it served 7 million pounds of organic beans in 2011, about 40 percent of the total it sold.

Chipotle also claims to be the restaurant industry's largest purveyor of "naturally raised meat," which it defines as receiving humane treatment and no hormones or antibiotics. Even during the years when Chipotle was majority-owned by fast food behemoth McDonald's (which began backing founder Steve Ells' business plan in 1998, allowing the chain's expansion beyond Colorado, and sold out only in 2006), Chipotle held firm that it would serve ethically produced meat whenever possible. Even the company's critics (more on them in a minute) agree that it does laudable work to better the existence of commercial livestock.

Family farms are another cause that Chipotle champions, often through the work of its in-house charitable foundation, Cultivate. Last year, Chipotle released another short film, "Abandoned," addressing the plight of small-scale family farmers. (Like the new film, this one also has a retro-hipster soundtrack, a Karen O. cover of "Mammas, Don't Let Your Babies Grow Up To Be Cowboys." Brilliant? Quite possibly.) The progressive company even sponsored free screenings of Robert Kenner's documentary Food, Inc. in 2009. So far, so good.

I see one fly in the Chipotle kitchen, though, and it's the company's attitude toward labor practices. Like many fast food restaurants, Chipotle relies heavily on immigrant workers. The chain was targeted by the U.S. government in a 2010 Immigration and Customs Enforcement audit. It quickly dumped hundreds of undocumented workers, which led to a backlash from both sides of the immigration debate.

And another labor issue gets right to the heart of the "Food With Integrity" stance: Chipotle long resisted extending its ethical practices to the treatment of workers elsewhere in the supply chain … which brings us to the territory of one of my fellow OnEarth contributors, Barry Estabrook: the tragedy of American tomato farming.

If you've read Barry's brilliant, infuriating 2011 book Tomatoland (and if you haven't, do it now -- I'll wait), you know that most off-season tomatoes in this country are produced in Florida and, at some point in their journey from field to plate, handled by slave labor. If you're new to this story, I'll wait while you read that sentence again. Yes, we're talking about real slaves: workers who have been kept against their will, through intimidation and physical violence, and held in indentured servitude while working in Florida's tomato fields. (If you don't have time for Tomatoland, Barry's 2009 article "The Price of Tomatoes" in Gourmet magazine will give you the horrifying basics.)

A group of these farm laborers organized themselves in 1993, creating the Coalition of Immokalee Workers to improve the lot of the pickers. In the last decade, aided by the coalition, the state of Florida has successfully prosecuted seven slavery cases involving more than 1,000 farm workers. One of the coalition's key strategies is to improve conditions for workers by getting tomato customers (the big ones: fast food chains, grocery store chains, institutional food providers like Aramark and Sodexo) to agree to a one-penny-per-pound increase in the price they pay for tomatoes. This tiny increase translates to a 64 percent increase in the wages paid to pickers -- the difference between a life far below the poverty line and one where workers can just squeak by.

Companies who have signed the workers' Fair Food pledge now include food service giants Aramark and Sodexo and fast food leaders Burger King, Taco Bell, and, believe it or not, McDonald's. Last week, Trader Joe's signed on. One notable holdout? Chipotle.

Chipotle consistently resisted the coalition's efforts, unmoved even by a public letter signed in 2009 by (among many others) its Food, Inc. allies: director Robert Kenner and writer and activist Eric Schlosser (Fast Food Nation). Protesters supporting the Coalition of Immokalee Workers showed up at several Food, Inc. screenings. Then, to the outrage of many food activists, Chipotle loudly (and incorrectly, say critics) took credit when a separate agreement to enact the "penny per pound" price rise was negotiated by the coalition with large tomato grower East Coast Farms.

At the time, Chipotle said its refusal to sign the pledge hung on the coalition's inability to enforce its victory: a consortium of tomato growers was refusing to pass the price increase on to the workers, as was intended. Since that time, says coalition spokesman Marc Rodrigues, "With the growers, we've actually had a major breakthrough. In late 2010 the Florida Tomato Growers Exchange relented and signed an agreement with the CIW. In many ways we're actually seeing the dawn of a new day in Florida's fields as a result of this agreement and our ability now to implement the CIW's Fair Food Program on farms across the state."

And Chipotle? Though it has continued to resist following the lead of the fast food industry's major players, the chain now buys its Florida tomatoes from the same Fair Food-compliant distributor that McDonald's does. As a result, says Chipotle spokesman Chris Arnold, "All of the Florida tomatoes we buy come from growers who have signed on to this program to pay an additional 'penny per pound' for tomatoes their workers harvest."

Until Chipotle signs its Fair Food pledge, though, the Coalition of Immokalee Workers remains unsatisfied. Says Rodrigues: "The difference between Chipotle and McDonald's, and the concern that we have, is commitment. Without a real commitment to the Fair Food Program, Chipotle could decide next week or next month or next year, or whenever it feels like the public scrutiny has waned, to stop paying the penny premium."

I'm a fast food avoider who has only ever eaten one not-so-memorable meal at Chipotle, so I can't fairly comment on the tastiness of its carne asada. But I admire the company for bringing the issue of factory farming to a wide audience. And I applaud its work on behalf of the treatment of livestock, which may well have influenced the McDonald's decision this week to ask pork suppliers to stop using inhumane gestation crates.

Is Chipotle's record unblemished? No. Is the company working to practice environmentally responsible big business? Yes.

Let's hope Chipotle continues to encourage humane treatment, throughout its food supply chain, so it can truly live up to the commitment to "Food With Integrity." Here's an idea: maybe its next film could expose the plight of farm workers and announce the company's adoption of the Fair Food pledge. Now that's an idea that would definitely bring tears to my eyes.