More than 400 American meatpacking plants inspected by European technicians have failed to meet European Economic Community (EEC) standards, but the inspection reports have been stamped "confidential" by the State and Agriculture departments on grounds of potential damage to national security.

The standards were adopted in 1972, and most countries that send fresh meat to the EEC have complied with them. Enforcement on American meat exports to Europe is to begin next October, an action that could put a substantial dent in the amount of U.S. meat allowed into the European market.

The inspection reports on American packing plants were compiled by teams of EEC technicians beginning early last year. More than half of the plants that failed would require major changes to meet EEC standards. The rest could comply by making less rigorous changes in their procedures.

A spokeswoman for the Agriculture Department's Food Safety and Inspection Service (FSIS), which asked State to wield its classification stamp earlier this year, said the action was taken at the request of the EEC and because USDA feared that disclosure would undermine American consumers' confidence in the quality of their meat.

"People would talk about these as deficiencies, and we don't consider them deficiencies," said Nancy Robinson of the FSIS. "We're saying that the EEC's requirements are different than ours, but that ours bring the same quality and wholesomeness."

Ella Krucoff, an EEC official in Washington, said "many" of the 400 inspected plants eventually will meet the EEC standards because the argument involves inspection methodology rather than sanitation.

According to the USDA, differences include such issues as systems used for cleaning vehicles and disinfecting plants, types of equipment allowed in U.S. plants, the extent of veterinarian involvement in the inspection process, post-mortem inspection procedures and certification of plant employes' health.

American and EEC officials, meanwhile, are continuing high-level negotiations aimed at resolving the dispute over the standards. In case the negotiations fail, however, the USDA has set up a technical assistance program to help U.S. packers come into compliance with the requirements if they intend to continue exporting to Europe.

Last year, the meat trade was in rough balance. The United States sent 308 million pounds of fresh and frozen red meat and edible organs to the EEC; about 322 million pounds of red meat came here from Europe. About one-sixth of the U.S. exports were horse meat, according to USDA records.

Officials on both sides acknowledge that the dispute stems more from major differences in inspection and sanitation requirements than from disagreement over the quality of product. The EEC visits, however, resulted in a warning to community members that purchases from 11 plants should stop now because of unsanitary conditions.

Both sides also acknowledge the "sensitivity" of the dispute, which is one of a number of contentious agricultural trade issues separating the EEC and the United States. Both sides have indicated guarded optimism about a settlement before the enforcement deadline next fall.

But in a letter to Rep. Ted Weiss (D-N.Y.), chairman of a House Government Operations subcommittee that sought copies of the EEC reports, FSIS official L.L. Gast said, "We cannot overemphasize the potential damage to U.S. agricultural export markets that could result from improper disclosure of these reports.

"We believe that the EEC would be seriously offended by such disclosure; that there would be on the part of the U.S. industry a vocal demand for retaliatory actions by the U.S. . . . and that the American public would be seriously misled about the regulatory protection of its meat supply," Gast said.

An aide to Weiss indicated that the subcommittee has taken no further action on the issue of classification because of apparently legitimate differences between the two sides over the adequacy of their respective meat inspection procedures.

"It is highly sensitive because of the consumer and national interests," said the EEC's Krucoff. "I've had some calls from around the country from excited consumer reports . . . . There is a lot of alarm in local communities about whether people are getting bad meat and whether USDA standards are good enough."