The U.S. Department of Agriculture estimates that 21 percent of the available food in the nation goes uneaten by consumers.

The agency unveiled a new tool Thursday in its efforts to reduce the amount of food waste in landfills.

Foodkeeper, a free app for smartphones and tablets, offers users detailed information about how to properly store food and when it is likely to spoil.

Kootenai County Solid Waste Department Principal Planner Laureen Chaffin said food scraps account for 26 percent of the waste received at the county's two landfills. Having that organic material is a positive, she said, because it allows the department to produce more methane gas, which is used to generate electricity.

"But I also recognize that part of our goal is to save as much air space as we possibly can in the landfill so it has a longer life," Chaffin added. "So I'm pleased to see that the federal government is doing something that gives the consumer a little bit better way of planning ahead."

The app offers Android and Apple device users storage timelines for more than 400 food items, and cooking tips for meat, poultry, seafood and egg products.

Consumers can also use the Foodkeeper app to track the freshness of foods in their pantries and refrigerators. Calendar integration allows users to enter the purchase dates for products and offers notifications when products are nearing the end of their recommended storage timelines.

The development and launch of the Foodkeeper app is part of the U.S. Food Waste Challenge, a campaign launched in 2013 by the USDA and U.S. Environmental Protection Agency. The challenge calls for organizations and individuals throughout the food chain - including farms, food manufacturers, grocers and restaurants - to reduce food waste through better purchasing, storage and inventory processes. The effort works to connect potential food donors with food banks and recycle food waste to create compost and other agricultural products.

Carolyn Shewfelt, manager of the Community Action Partnership food bank in Coeur d'Alene, said her organization relies heavily on what they call their "grocery rescue program."

"It's most of our food that comes in, and goes right out the door," Shewfelt said.

Food bank personnel visit local grocers, she said, and pick up foods the businesses cannot sell - perishable items that are safely edible but past their "sell-by" dates or have been "rotated out" with fresher items.

Most stores in the area donate bread items, she said.

A few donate meats, but there are two local grocery stores that don't because of corporate policies. Shewfelt would not name the stores.

"The local managers are really frustrated. It's not that they don't want to donate the meats ... some of them actually throw it into the garbage," Shewfelt said.

The quality of the items the food bank picks up through the grocery rescue program is mainly good, Shewfelt said.

A strawberry or blueberry might have some mold on it, but that happens when consumers buy those items off the shelves at the store, she said.

"We do what everybody does. We just pick them out," Shewfelt said. "The stuff that is not good enough quality to give out, we put in bins for our pig farmers, so they can turn it into bacon."

Staff writer Maureen Dolan contributed to this story.