The nation's food banks, struggling to meet demand in hard times, are turning to prison inmates for free labor to help feed the hungry.

Several states are sending inmates into already harvested fields to scavenge millions of pounds of leftover potatoes, berries and other crops that otherwise would go to waste. Others are using prisoners to plant and harvest vegetables.

"We're in a situation where, without their help, the food banks absolutely could not accomplish all that they do," said Ross Fraser, a spokesman for Feeding America, a national association of food banks.

The number of Americans who couldn't afford food jumped 30 percent from December 2007 to December 2008, according to a survey by the group. Demand at some pantries have more than doubled, Fraser said, as job losses and wage cuts have strained family budgets.

State governments, with their own historic revenue shortfalls, can't keep pace with the need. Many have cut budgets of social service agencies, including those that provide food assistance to the poor.

Ohio and Michigan are among states that have expanded inmate farming projects specifically to feed the hungry. Other states, including Illinois and California, have increased help to food banks.

Texas and Arkansas plan to enhance their food bank work-training programs, which provide labor and help make offenders employable when they're released. Food banks use inmates to sort, clean, shelve and cook food.

A 23 percent increase in food demand in Arkansas prompted Gov. Mike Beebe to allow inmates to gather otherwise wasted crops for food banks, said Phyllis Haynes, executive director of the Arkansas Food Bank Network.

Outside the Faith Mission in downtown Columbus, Ohio, Catherina Moore, 26 and homeless, said she's concerned that criminals might tamper with soup kitchen food. But she supports the practice of teaching farming skills to inmates.

"There's nothing wrong with teaching a man to grow food," she said. "A person can use those skills to survive. I think they deserve that training."

Most of the prisoners who work in food bank programs are nonviolent, short-term offenders convicted of such crimes as drug possession or theft, prison and food bank officials said.

"Prisons are full of people who have taken all their lives, and this is giving them an opportunity to give back," said Ernie Moore, assistant director of the Ohio Department of Rehabilitation and Correction, whose farming program begins with donated seeds and fertilizer from the state food bank network.

Alison Lawrence, a policy specialist at the nonpartisan National Conference of State Legislatures, said states battling high unemployment have found little downside to using inmates to fill food banks' mostly volunteer jobs.

"The underlying economic factor you have to weigh as a state with inmate labor is whether they're taking jobs from free, able-bodied people," she said.

In some areas, established inmate farm programs, seen as uneconomical or not relevant, are being eliminated.

New York plans to cut its state prison farm program later this year because the rural farming skills it teaches are viewed as impractical to prisoners returning primarily to urban settings.

In Arizona last year, food banks barely managed to save a program that uses inmate labor in Maricopa County.

Ginny Hildebrand, president and chief executive of the Association of Arizona Food Banks, said the state initially said it was too costly to employ enough guards to prevent inmate escapes. But the food banks argued that axing the program would mean the loss of millions of pounds of produce gathered by inmates at a time when demand had jumped 43 percent.

Eric Cooper, executive director of the San Antonio Food Bank, said inmates in the Texas Second Chance program can learn skills used at the warehouse where donated food is stored, such as forklift operation, inventory and sanitation. Or they can enroll in the food bank's culinary school, cooking for soup kitchens and learning food safety and the tools of the hospitality trade.

"It's an incredible win for them, the students, to be able to come out of prison each day and work a full day with us, to get a great meal there at the food bank, and to learn skills that will translate into good-paying jobs," Cooper said. "Meanwhile, the food bank gets a great source of labor."

Participating in Second Chance was a game changer for Peter Worthen. At 28, he's now out of prison and working as inventory coordinator at Cooper's food bank.

"Rather than being with all the drama inside the unit all day, it was an advantage to get out and do something different, to work around people, and learn new skills," said Worthen, who served 23 months for marijuana possession.

"Since you're working for free regardless, it just felt better that somebody was being helped out by what you did."