* High commodity prices lead to drop in gov't food donations
* Food banks increase food purchases, straining resources
* Hunger relief groups bracing for more cuts to food stamps
LOS ANGELES, Nov 21 (Reuters) - The worst U.S. drought in more than half a century has weakened the safety net for the 50 million Americans who struggle to get enough to eat, and the nation's food banks are raising the alarm as the holiday season gets into full swing.
Demand for food assistance - unrelenting as the U.S. economy slowly recovers from the worst recession since the Great Depression - ticks higher during the winter holidays.
This summer's crop-damaging weather in the U.S. farm belt has driven up costs for everything from grain to beef. That means higher prices at the grocery store, but it also means the U.S. government has less need to buy key staples like meat, peanut butter, rice and canned fruits and vegetables to support agricultural prices and remove surpluses.
Most of the products from those government purchases are sent to U.S. food banks, which then distribute them to food pantries, soup kitchens and emergency shelters that are a lifeline for people who struggle with hunger - including low-income families, senior citizens and people with disabilities.
The decline in government donations is exacerbating the pain inflicted by stubbornly high unemployment and a lack of income growth for many low-wage workers.
"People have been coping with economic distress for a really, really, really long time ... After several years of tapping all the resources we have, we're starting to see that we're coming up short," said Carrie Calvert, director of tax and commodity policy at Feeding America, the nation's largest hunger relief organization.
Executives at major food banks across the United States worry they will not be able to keep pace with demand, which they don't expect to ease until more Americans find better paying jobs. In a sign of how stressed the budgets of many Americans are, a record 47.1 million people used food stamps in August 2012, up from 45.8 million the year earlier.
With such pressures at work, on-hand supplies at the Los Angeles Regional Food Bank have fallen from a peak of about 3.3 weeks in 2010 to less than two weeks - the lowest in recent history, according to its president and CEO, Michael Flood.
Tightening food supplies last summer forced the food bank to start a waiting list because it does not have enough inventory to expand beyond the 640 agencies it already supplies with food. There are now 565 nonprofits on the waiting list, Flood said.
Government commodity purchases through The Emergency Food Assistance Program (TEFAP) fell by more than half to $352.5 million for the fiscal year ended Sept. 30, from $723.7 million three years earlier, according to the U.S. Department of Agriculture.
While the stated goal of such purchases is to support agriculture prices and remove surpluses, they also have been vital to fighting hunger.
USDA told Reuters it would do all that it could through TEFAP to support hunger relief efforts. It already is assisting in New Jersey and New York, which were hard hit by Superstorm Sandy.
Government commodities once made up 28 percent of the food flowing through the Feeding America network, which includes about 90 percent of U.S. food banks and provides food for about 37 million people during the year. This year those commodities account for 17 percent, Feeding America said.
The Second Harvest Food Bank of Northwest North Carolina has seen its monthly supplies of TEFAP products plummet by roughly two-thirds to about 170,000 pounds from 500,000 pounds. At the same time, state budget cuts have slashed its annual funding by about half to $500,000, Executive Director Clyde Fitzgerald said.
"Either one without the other would be enormously adverse to our ability to meet the need," Fitzgerald said. "We've spent $1 million buying food, but we haven't come close to making up for that shortfall."
Barbara Prather, executive director of the Northeast Iowa Food Bank, also is buying more food after government commodity donations fell by 50 percent to 700,000 pounds in the fiscal year ended June 30.
"We were, because of purchasing and local donations, able to bridge that gap by about 300,000 pounds, so our net difference was about 400,000 pounds," Prather said.
The picture is similar elsewhere.
At the Greater Chicago Food Depository, food purchases have more than doubled in recent years to account for 27 percent of overall supply, a spokesman said.
That strain shows up in the size and quality of food packages that nonprofits give to people who need to supplement food stamp benefits or whose meager incomes are a bit too high to qualify for food stamps or other government assistance.
Last week, women with young children, single men dressed in combat fatigues and senior citizens - some in wheel chairs - gathered at Monrovia, California's Foothill Unity Center to pick up rations, including staples like eggs, salad, milk and bread.
"We used to give more in those shopping carts," said Betty McWilliams, the executive director of the Los Angeles-area center. For example, carts now have six or seven cans of food rather than nine, she said.
Thus far the center, which is supplied by the Los Angeles Regional Food Bank, has not had to turn anyone away.
Rochelle Fisher, 52, was grateful for what was available and credited the center's free food and healthcare services for getting her back on her feet.
"If they wouldn't have been there for me, I would have been starving to death," said Fisher, who just got a job at a homeless shelter where she used to stay.
Anti-hunger groups expect some relief from a planned $170 million TEFAP purchase that will send pork, chicken, lamb and catfish to U.S. food banks over the coming months.
But they are bracing for more challenges in 2013. Food prices are forecast to move even higher, making it harder for people with limited means to stretch their money.
Current proposals for the new U.S. farm bill - which sets funding for TEFAP and the food stamp program - include small increases for TEFAP.
But those increases would be dwarfed by proposals for billion-dollar cuts to the food stamp program.
Washington's the "fiscal cliff" fight over planned tax increases and spending cuts due to start in January is adding to the anxiety, since sharply partisan U.S. lawmakers need to come together to avert a big hit to the economy that likely would hurt the country's most vulnerable.
Donors such as Wal-Mart Stores Inc and Kroger Co say they have increased both cash and food donations.
Most food bank executives quoted in this article said private and corporate donations seem to be holding up, despite increased competition for every dollar. Still, they say such charity is not enough to offset the decline in federal support.
Joel Berg, executive director of the New York City Coalition against Hunger, worries that funding for feeding programs could fall victim to the optimistic American view that things will always work out in the end.
"Often, in the real world they don't. People suffer more," Berg said.