Furthermore, ConAgra was not required to immediately report the positive results to the Department of Agriculture, a "gaping loophole in our nation's food-safety laws," according to the letter, signed by Rep. Henry Waxman, D-Calif, Sen. Dick Durbin, D-Ill., Rep. Marcy Kaptur, D-Ohio, Rep. Rosa DeLauro, D-Conn. and Rep. Sherrod Brown, D-Ohio.
The E. coli findings came about a month before the production cycle that turned out 19 million pounds of beef linked to 20 E. coli infections across several states. The beef was recalled later.
But the Greeley plant, now under the name Swift & Co. after ConAgra sold its beef and pork division to a management company, was not required to immediately turn over the results to the government, according to the letter.
"Current USDA policy is to hope companies will act responsibly," the lawmakers wrote. "But this voluntary approach appears grossly inadequate to protect the public health."
Also, ConAgra did not "take legally required steps to end the life-threatening contamination," wrote the lawmakers, who demanded that Agriculture Secretary Ann Veneman consider seeking criminal penalties against the company for its "apparently reckless" behavior.
James Herlihy, a spokesman for the plant, said the plant followed all USDA reporting requirements.
"Any internal test results that may indicate a potential positive for E. coli are documented and made available to the USDA," Herlihy said.
Herlihy said the company did not know what, specifically, the letter alleges to be illegal behavior in not ending the contamination.
"We're not aware of anything being done that was not legal or any regulation that was not complied with," he said.
William Marler of Seattle, an attorney for 31 people sickened by the beef, said information uncovered in his litigation showed the E. coli was found in finished beef product and that ConAgra discarded only the 1,000-pound test lots and not any other beef in the day's production.
But Marler said lax USDA policies were mostly at fault.
"ConAgra was doing exactly what the government told them to do," he said. "But the government really failed us by not simply mandating that, if you get a positive E. coli test day after day after day, you should tell us."
The letter to Veneman also said that USDA inspectors "may have missed two opportunities to recognize the severity of the contamination" back in May, because the USDA did not know of ConAgra's positive E. coli results.