The fight to improve wages for Florida's tomato pickers hit the national stage over the past week, as part of the race for the Democratic presidential nomination.

Last Saturday, Vermont Democrat Bernie Sanders' campaign released a five-minute documentary highlighting the struggles – and successes — of tomato pickers in Immokalee, Fla. As Barry Estabrook documented in his 2011 book Tomatoland, these workers faced poverty wages and were subjected to pesticide-laden fields, abusive bosses and slave-like working conditions.

As we've reported, over the past half-decade, conditions have been improving for these workers, thanks to a combination of measures, including a premium of a penny-per-pound that corporate buyers like Wal-Mart and Whole Foods pay to growers.

The video from the Sanders campaign notes that the senator held hearings on the matter back in 2008, before efforts to improve the workers' lot had gained much traction. As the narrator, an unnamed female tomato worker originally from Mexico, says in the video, not many politicians visited Immokalee, but Sanders was there to support their fight.

And those hearings became the focus of a testy exchange between Sanders and Hillary Clinton at last night's debate in Miami. Clinton accused Sanders of siding with "Minute Men" and Republicans who voted against a 2007 immigration overhaul bill that, among other things, would have expanded the guest worker visa program.

That program would have let foreign workers in for two years at a time, but critics argued that it offered very few protections for workers. Sanders has said he opposed the bill because it would have left immigrant workers more vulnerable to exploitation and would have ultimately depressed wages for Americans, too.

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