For Wal-Mart, which gets more than half of its sales from food and other groceries, the partnership is part of a strategy of working closely with suppliers to come up with new twists on existing foods or developing new ones, and getting them to the shelves faster. The company opened a food lab in June for that teamwork, a process that can cut costs and shave several months off a product launch, says Charles Redfield, executive vice president of food at Wal-Mart.