U.S. Warns of Contaminated Dairy Products : Sanitation: Agriculture Department investigators say checks of some plants turned up rodents and insects in processing areas.

Contaminated butter, cheese and other dairy products could be reaching the nation’s groceries because processing plants are being allowed to operate under unsanitary conditions, Agriculture Department investigators say.

The department’s office of inspector general said in an audit that its checks of processing plants turned up rodents and insects in processing areas, mold on ceilings and walls and peeling paint or insulation dangling from ceilings above open cheese-making vats.

The audit said the department’s Agriculture Marketing Service had failed to identify violations at some plants or to promptly notify state or federal regulators who have authority to shut the plants.

“As a result, tainted or unwholesome products could be distributed to the public during the periods that such plants are allowed to continue to operate under unsanitary conditions,” said the audit, which was dated March, 1991.

It was obtained by the Associated Press under the Freedom of Information Act.

The report does not speculate on how much of a health threat the contamination could pose.

But Rod Leonard, executive director of the Community Nutrition Institute, a private group focusing on food safety, said the unsanitary conditions are an “indication that the first line of food safety defense has been breached. And sometimes you can’t correct it quick enough to prevent someone from getting sick.”

Floyd Gaibler, executive director of the American Butter Institute and the National Cheese Institute, which represent the butter and cheese manufacturers and processors, said he had not seen the report and therefore would not comment on it.

“Our products are of high quality, and they are quite safe for human consumption,” he said.

Clarence Steinberg, a spokesman for the marketing service, declined comment beyond the agency’s response included in the audit report.

The report said the marketing service has agreed to notify state or federal regulators within two working days whenever significant sanitation problems are identified in plant inspections. The agency is also seeking additional money to expand supervision of the inspections and to begin a training program.