Bent on making fresh fruits and vegetables available to more Americans, the U.S. Department of Agriculture sent one of its top officials Thursday to the Clark Park Farmers Market to tout its efforts at doing just that.

"We're trying to nudge low-income households to eat more nutritious foods," U.S. Department of Agriculture Under Secretary Kevin Concannon said in an interview before talking to the merchants and shoppers about ways to get more healthy foods in their diets.

Americans on food stamps spent a record $18.8 million at farmers markets and local farm stands last year, a roughly sixfold increase since 2008, according to Concannon. Some of that increase was due to low-income families having more access to fresh produce.

Looking around the farmers market at 43d Street and Baltimore Avenue, which has only been around since 1999, the fruits of those efforts were on display.

While some shoppers handled and assessed the fruits and vegetables nestled among the nutrition bars and other prepared foods for sale under two rows of tents, others watched a food demonstration on kale.

"Chef Stephen" - Stephen Schaeffer of the Food Trust, a Philadelphia nonprofit that focuses on nutrition education and access - prepared a kale salad as a colleague engaged roughly a dozen onlookers with an animated conversation about the importance of fiber. It lowers cholesterol, among other benefits.

The Food Trust puts on food demonstrations such as this every week.

"We want people to take advantage of the market," Schaeffer said.

Bringing fresh and healthy foods to low-income families - who often lack access to expensive fruits and vegetables - is a challenge.

To that end, Concannon said Department of Agriculture officials have been charged with increasing the number of farmers markets that take food stamps, formally known as the Supplemental Nutrition Assistance Program and commonly referred to as SNAP. They also need to encourage low-income families to purchase fresh food at those markets.

Roughly 6,400 farmers markets nationwide now accept SNAP, compared to 753 in 2008, according to the Department of Agriculture.

In Pennsylvania, 181 markets participate in the program. SNAP redemptions in the state totaled $414,624 in fiscal year 2014, up from $9,358 in 2008.

Concannon attributed the increase to several recent USDA efforts, such as offering participating farmers markets wireless equipment to instantly process SNAP benefits electronically.

The USDA has also tried to incentivize shoppers to go to farmers markets through its Food Insecurity Nutrition Incentive grants, awarded to organizations to develop programs to encourage low-income families to buy healthy food.

A FINI grant funds Philadelphia's Philly Food Bucks program, for example, which offers low-income shoppers a $2 coupon to buy fruits and vegetables when they spend $5 in SNAP benefits at participating farmers markets.