Washington ? A congressional committee is investigating whether some private U.S. laboratories were instructed to withhold samples of tainted food so importers could get their goods into the U.S.

In a May 1 letter to 10 labs, the House Committee on Energy and Commerce suggests that they may have been encouraged by importing companies to discard test results that failed Food and Drug Administration standards.

“We’re gathering information from both the FDA and private industry about the labs almost being complicit in helping importers game the system,” said Rep. Bart Stupak, D-Mich., chairman of the Oversight and Investigations subcommittee that is investigating the labs and food companies. “Someone told us you pay for the result you want to get from the labs.”

The committee’s letter reiterates Stupak’s suspicion that testing on some samples was conducted repeatedly until the food passed. In other instances, the letter states, importers whose food failed tests at one lab would hire a different lab to continue testing until it obtained a positive result.

“This repeated testing is done without alerting FDA that potentially dangerous food has been imported into this country – a practice which we find deplorable,” the letter states.

The committee has also asked 50 multinational food companies for a wide range of recall and food import records dating back to 2000. A May 8 letter from the committee to the companies asks about instances when food was found to be contaminated with chemicals or bacteria such as E. coli, salmonella or listeria.

“We wish to assess the extent of microbiological and/or chemical contamination occurring during the processing of food and the extent to which controls have failed to prevent or eliminate contamination in food,” the committee wrote.

The role of food testing laboratories became an issue in February, when the CEO of one private lab, Anresco of San Francisco, said private labs don’t always tell the FDA when tests show that imported food may be contaminated.

That executive, David Eisenberg, told the committee that the FDA “requires that we sign a laboratory director’s statement that we’re submitting all work that we’ve done on a sample.” But in reality, he added, the importers that hire the labs control where the test results go.

“If the importer tells us not to submit the information to the FDA, the FDA never sees it,” Eisenberg testified under oath.