A mail truck drove into the parking lot of a Cub Foods in Bloomington Saturday afternoon and pulled up next to a large moving van.

The postal worker wasn't there to deliver mail. Instead, he opened the truck door to reveal dozens of bags filled with food donations. One by one, volunteers carefully placed the bags in two large boxes.

Once filled, the boxes will go into the moving van and be driven to one of the local headquarters for Second Harvest Heartland, an organization that supplies donations to food shelves in Minnesota and Wisconsin.

Across the country, thousands of letter carriers went on their usual routes Saturday to pick up donations left in mailboxes for the 25th annual Stamp Out Hunger Food Drive, the largest single-day food drive in the United States.

In the greater metro area, those donations were taken to more than 20 Cub Foods stores, where hundreds of volunteers hoped to collect more than 1.2 million pounds of food.

"It seems like every year the need is growing," said Samantha Hartwig, food drive coordinator in the Twin Cities. "This food drive really helps out a lot of families in the community."

Stamp Out Hunger, which is organized by the National Association of Letter Carriers, has collected more than 1.5 billion pounds of food nationwide in its 25 years.

In last year's food drive, the Twin Cities fell short of its goal of 1.2 million pounds of food. Those donations help stock food banks and pantries for up to six months.

"People tend to give more when the weather is nice," Hartwig said. "Even if we don't hit our goal, it's food that wasn't there yesterday that will be there tomorrow."

Additionally, the Land O'Lakes Foundation matches up to $25,000 of monetary donations made online at 2harvest.org through May 18.

While all groups of people rely on food banks for nutrition, seniors are the fastest-growing population using them, Hartwig said. She attributes this to rising costs of living, which make it harder for people on fixed incomes to get by.

Heather Olson, director of corporate partnerships for Second Harvest Heartland, said one in 10 Minnesotans experience hunger, more than half a million people.

"Today makes a huge dent," she said.

Terri Krysan was the site coordinator outside the Cub Foods on France Avenue in Bloomington. An Iowa State University alumna, she was there as part of the school's volunteer program.

"This is one of those things, on a Saturday, when a lot of us can come, spend a few hours and do a good deed," she said.