Farmworkers were leading a five-day, 45-mile (72-kilometer) trek this week from one of Florida’s poorest communities to a mansion-lined waterfront city that is one of its wealthiest in an effort to pressure retailers to leverage their purchasing power to improve worker pay and working conditions.

Farmworkers said they were marching to highlight the Fair Food Program, which has recruited companies like McDonald’s, Walmart, Taco Bell and Whole Foods to use their influence with farmers to ensure better working conditions and wages for farmworkers. They hoped to use the march to pressure other businesses, including Publix, Wendy’s and Kroger, to join the program that began in 2011.

The march began Tuesday from the farming community of Pahokee, one of the poorest in Florida, where median household income around $30,000. The march’s starting point was a camp where farmworkers were forced to work for barely a paycheck by a labor contractor who was found guilty and sentenced last year to nearly 10 years in prison. The contractor confiscated the passports of the Mexican farm workers, demanded exorbitant fees and threatened them with deportation or false arrest, according to the US Department of Justice.

The protesters were scheduled to arrive Saturday in the town of Palm Beach, which has a median household income of nearly $169,000 and is lined with the mansions of the rich and famous, including billionaire Nelson Peltz, who is the chairman of Wendy’s, and former President Donald Trump.

According to the Florida-based Coalition of Immokalee Workers, which organized the march, the program has ensured that farmworkers are paid for the hours they work; it guaranteed them security measures at work such as shade, water and access to bathrooms; and has reduced threats of sexual assault, harassment, and forced labor under armed guards in fields where tomatoes and other crops are grown. Immokalee is a southwest Florida farming town in the heart of the state’s tomato-growing area.

Growers have benefited as it reduces turnover and improves productivity, according to the coalition.