Kraft Food Group said about 735,000 cases of packaged cheeses in U.S. markets could spoil ahead of their labeled best buy date, forcing a product recall. The company said it was voluntarily recalling some varieties of Kraft and Polly-O string cheese and string cheese twist products, due to premature spoiling that could lead to product discoloration. The affected products, in 22 packing variations, all have code dates from Oct. 25, 2013 through Feb. 11, 2014, Kraft said. Kraft said it had received customer complaints that prompted the recall and that it was investigating the cause of the spoilage that involved products from a production facility in Campbell, N.Y. In the meantime, the company said it had \"ceased the production and distribution of the affected products from the relevant facility.\"