Meat inspectors repeatedly warned the Agriculture Department (search) that ground beef at a ConAgra (search) plant was contaminated with harmful bacteria months before a food-poisoning outbreak last year, but their concerns were ignored, an audit by the department's inspector general says.

According to the report obtained by The Associated Press, inspectors informed their managers at the department's Food Safety and Inspection Service (search) that meat at the Greeley, Colo., plant was testing positive for E. coli, but "supervisors were not always responsive to the inspectors' concerns relating to increasing levels of fecal contamination and positive E. coli testing results," auditors wrote.

E. coli, a bacteria found in cattle feces, was a continuous problem at the plant from January 2001 until the summer of 2002, when ConAgra issued a recall for 19 million pounds of meat linked to the outbreak, said the audit, to be released Friday.

If the department had evaluated the plant, it might have been able to conclude that the contamination problem at ConAgra was severe, "but FSIS did not perform any of these reviews," auditors wrote.

The audit also found that inspectors didn't perform their own tests and failed to review other test results available to them, even though law requires them to. However, the auditors blamed some of the inspectors' shortcomings on gaps in the Agriculture Department's meat safety policies.

For instance, the government didn't require plants like ConAgra to be subjected to testing by its inspectors, leaving it up the company to check for bacteria. Inspectors were unsure whether they had the authority to review the company's test results, so they didn't ask to see them, the audit said.

Still, "if the inspectors had reviewed the test results and been fully aware of the scope of the problem, they may have been in a better position to take prompt enforcement action," the auditors wrote.

In addition, auditors concluded the department does not want responsibility of overseeing its core meat safety program, hazard analysis and critical control point (HACCP). The program requires companies to come up with a plan to prevent meat contamination and get it approved by the government.

Garry L. McKee, administrator of the Food Safety and Inspection Agency, said auditors cannot blame the entire HACCP system for the problems that led up to the ConAgra recall.

"While we welcome the work that went into this report, FSIS feels it reflects conditions that existed more than one year ago at a single plant," he said. "Those conditions were not reflective of HACCP enforcement at the time, nor do they bear any resemblance to the state of HACCP enforcement programs today."

He said the department has corrected the problems noted in the audit, noting that the department now requires all beef plants to be subjected to government testing for E. coli.

Auditors also said ConAgra failed to respond to the contamination quickly. They noted the company was aware its own tests on meat trimmings, which are ground into hamburger, showed 63 samples were positive for E. coli months before the recall.

The company also "failed to provide assurance that the physical and biological hazards to the production process had been identified and controlled," the audit said.

Jim Herlihy, a spokesman for Swift & Co., which now owns the ConAgra plant, said the plant has added measures to guard against E. coli, such as using a hot water wash to clean away bacteria and holding products until tests show they are disease-free.

"We do treat every one of those positive test results as a warning, and we do examine them thoroughly to determine the most appropriate response," Herlihy said.

The audit was prompted by the Senate Agriculture Committee and sought by Rep. Henry Waxman, D-Calif.

Waxman said, "One can conclude from this report that last year's outbreak of life-threatening E. coli O157:H7 infections may have been prevented had USDA or ConAgra responded to numerous warning signs."

Sen. Tom Harkin, D-Iowa, who was chairman of the Senate Agriculture Committee at the time of the recall, said Congress should write legislation to close loopholes in the department's meat safety policies.