Supply chain experts at Burgerville worked closely to develop specs and safe handling procedures with Liepold Farms, supplier of berries for the chain's seasonal milkshakes.

"It's a great differentiator. Not many [chain] restaurants do this," says Jeff Harvey, chief executive of Burgerville, a Vancouver, Wash.-based restaurant chain that sources the majority of its products from local producers.

Yet sourcing ingredients locally raises serious food safety concerns: Are local producers properly inspected? Are they practicing sound food safety techniques in their growing fields and processing plants?

Seattle attorney Bill Marler, a well-known food-safety expert, ranks "local food and/or farmers markets" second among the most important food safety challenges this year. "Community-supported agriculture groups and food co-ops need to demonstrate knowledge and practice of food safety, and be inspected. In addition to produce and meats/fish, prepared items are currently unsupervised in some but not all locations," he writes on his blog.

Despite the concern, the attraction of becoming known as socially conscious operator—and the ability to market that position—is hard for operators to resist given consumer interest. A survey from the National Restaurant Association shows that 70 percent of adults say they are more likely to visit a restaurant that offers locally produced food items.

Meatless burgers come fully cooked and frozen from a small company in Wilsonville, Ore.

Consider 39-unit Burgerville, which has hired five people in recent years to manage a supply chain infrastructure that depends heavily on local producers. About 75 percent of the quick-service chain's ingredient list is produced within a couple hundred miles from headquarters.

Harvey, who joined Burgerville as CEO five years ago, says the company first dipped its toe in local waters 13 years ago. When he arrived, he began "ramping up" the company's relationships with local vendors to make the chain distinctive. Today, Burgerville does business with 14 local vendors, which supply everything from smoked salmon to frozen yogurt.

Not all of these concerns are small and artisanal. Burgerville's french fry vendor, which happens to be located in Pasco, Wash., is one of the country's largest potato processors. Its frozen yogurt manufacturer, headquartered in nearby Portland, Ore., rang up $43 million in sales last year.

Small, artisanal purveyors, however, may spark worry that food safety standards are not as stringent as they would be in larger companies, a notion largely disabused by the recent spate of foodborne illness, which involved both industrial farms and processing plants.

Purchasing consultant Lauren Cahill-LeFranc says that small growers, particularly on organic farms, are likely to pay close attention to food safety practices. But she nonetheless advises operators to consider the whole supply chain scenario before making any purchase decisions. That would include, she adds, working with distributors who truck the product to your restaurants.

"What's the temperature chain from farmer to restaurant," Cahill-LeFranc explains. "A basic question is: Are your trucks refrigerated, and are the temperatures working?"

"That's a conversation everyone has to have, regardless of the size, regardless of location," offers Kathy Means, vice president of government affairs for the Newark, Del.-based Produce Marketing Association, which represents growers, distributors and restaurant companies. "I would ask the distributor, 'You've checked out this company's food safety program, right?' Or if you are buying it direct, then you check it out yourself."

Burgerville does. "We believe strongly that anytime we can build a relationship with a source, we feel better insofar as not only guaranteeing the safety of a product but sharing the story of a small, local producer practicing a sustainable business," explains Alison Dennis, director of supply chain. "Safety practices and process improvement opportunities are part of our ongoing supplier-relations dialog throughout the year."

Burgerville purchases ground beef from a co-operative of local cattle ranches, like this one in Brothers, Ore., that maintains control of the product until it reaches the restaurants.

It included working with the owners of Liepold Farms, a small grower in Boring, Ore., that supplies fresh strawberries, raspberries and blackberries used in the chain's seasonal milkshakes. "Alison went there and worked with leadership and spelled out the specs for our products," Harvey recalls, adding the farm ships the berries to a local processor, which turns them into slurry suitable for blending into ice cream. "She explained the condition the berries need to be in and how many twigs and leaves are acceptable."

Wait. Twigs and leaves? "Sometimes a bug or twig can get in there," Harvey notes. "It underscores the idea, 'Oh, I get it. This comes form the farm.'"

MORE: Many aspects of going green enhance, rather than compromise, food-safety programs.