"So has it been a good experience?" U.S. Department of Agriculture official Joani Walsh asked, snacking on cherry tomatoes as an elderly woman reached around her for the white sweet corn stacked high on the table.

As Walsh toured Clark Park Farmers' Market on Saturday, she was greeted with smiles and nods of approval.

She met various growers - the high school students experimenting with urban farming, the owner of a year-old mushroom farm - and talked with various customers, including a mother of four who drives from the suburbs several times a month and a local mother of seven who makes the short walk twice a week.

Walsh, deputy undersecretary for marketing and regulatory programs at the USDA, was speaking with producers and visitors as officials from the city's Department of Health and the Philadelphia nonprofit the Food Trust touted the city's successes.

"We've been paying a lot of attention to Philadelphia for quite some time. It's really exciting," Walsh said. "Philly's just really been out in front with some groundbreaking work."

Philadelphians have increased access to farmers' markets in the last few years, Walsh said, and that has led the way for the rest of the country.

Such progress is particularly important for Philadelphia, with its 25 percent poverty rate among the highest of major cities.

A combination of local, state, and federal programs are aimed at getting fresh and healthy food to the poor to combat high rates of obesity and diabetes.

At the Clark Park market, customers in the Supplemental Nutrition Assistance Program (SNAP) can purchase food by filling out vouchers at individual sellers' tents. Market workers process the vouchers using the customers' benefits card through the Electronic Benefit Transfer system (EBT).

The Food Trust, which runs the Clark Park market, also offers a "Philly Food Bucks" program, begun in 2008. For every $5 that SNAP recipients spend at farmers' markets, they receive a $2 coupon that can be used at various markets throughout the city. Nicky Uy, senior associate at the Food Trust's farmers' market program, said this year's goal is to redeem $50,000 in Food Bucks vouchers.

Other Food Trust programs enlist corner stores to offer healthy foods. School programs teach young people about nutrition.

The tour of the Clark Park market in West Philadelphia, the city's largest year-round market, was Walsh's last stop on a trip celebrating the federal agency's National Farmers Market Week. In declaring Clark Park Farmers' Market an example of Philadelphia's national leadership, Walsh cited the EBT machines, nutrition outreach, Food Bucks programs, and the Food Trust's close relationship with the city.

The Food Trust, established in 1992, operates 26 farmers' markets; 10 were opened in 2010 and 2011 in a partnership with the Philadelphia Health Departmentas part of the "Get Healthy Philly" initiative. The markets were placed in zip codes with the highest poverty rates.

The added locations, EBT accessibility, and Food Bucks vouchers have made a substantial difference, she said. Food Trust marketing has begun to focus on SNAP redemption and the Food Bucks program. Food-stamp purchases have more than quadrupled over the last two years.

"Our advertising has changed," Uy said. "We used to advertise that it's fresh, it's local, it's delicious, but now we just put 'ACCESS CARDS' front and center in our advertising. It drives people to market, because all of a sudden there's a new place in their community where they can spend their benefits, where they know it's fresh, high-quality, and they get to talk to the grower. They want the same things that everybody does."

Longtime customer Erin Brennan, 35, agreed, pointing to EBT access as an initial draw to Clark Park.

"I can use my EBT, I can ask [growers] how the food is grown, I can give my money directly to them," Brennan said. She makes the 25-minute drive several times a month from Collegeville, in part because her area markets don't take EBT cards.

Even if they did, she plans to keep coming to the Clark Park market. "I've formed a relationship with the people here," she said. "I wish that all of our local families would go to farmers' markets, but they also have no programs like the Food Bucks."