A loophole in the food safety system allows E. coli-contaminated ground beef to become part of pre-cooked products destined for the frozen foods section at grocery stores and school lunches through the USDA’s National School Lunch Program, according to the Chicago Tribune.

Food Safety and Inspection Service inspectors believe that the amount of E. coli contamination in ground beef products has not declined nearly as much as has been touted in the last several years.

If a company tests ground beef, and it is positive for E. coli and shifted to a "cook only" line, USDA testing is apparently not performed on the product.

After ConAgra recalled 19 million pounds of ground beef for E. coli contamination in 2002, the company planned to "recycle" the ground beef it recovered by using it in canned chili products and pet food. After consumers learned of ConAgra’s plan, the company ultimately announced that it was destroying the ground beef instead of re-using it.