The Chicago Tribune reports that the USDA knew of a positive E. coli test from a meat sample and a human sample over two weeks before a recall was initiated in regards to Topps Meat Company.

Amanda Eamich, a USDA spokeswoman, said that the USDA's recall committee first met on Sept. 25 to consider the Topps case, 18 days after E. coli was confirmed in a Topps hamburger, according to Robertson's e-mail, which was provided to the Tribune.

The committee, comprised of department officials, concluded then that it should request a Class I recall of the Topps meat. Class I is the USDA's most serious recall class. It means that there is "a reasonable probability that eating the food will cause health problems or death."