The U.S. Food and Drug Administration (FDA) has ordered the suspension of the food facility registration of Delaware food manufacturer Roos Foods, which has been identified as the source of the recent listeria outbreak, the federal agency announced.

The facility registration was revoked following an investigation by the U.S. Centers for Disease Control and Prevention, the FDA and a number of local agencies that revealed the multi-state outbreak was linked to cheese produced, stored or packed by Roos Foods. During the suspension period the company will not be allowed to sell or distribute food products manufactured at the facility, the FDA stated.

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As part of the inspection, the FDA took samples from various sections of the facility and found that 12 of the samples were contaminated with Listeria monocytogenes. Officials also detected a number of violations of safety practices, including serious problems with sanitation and hygiene.

According to the FDA, inspectors found that the roof of the facility was leaking and rain water was dripping directly into the cheese processing room, including onto processing equipment, while many metal parts of the ceiling and supports inside the facility were rusty and metal flakes prevented effective cleaning and sanitizing. In addition, food residue was discovered on various parts of the equipment despite the fact that it had already been cleaned. The FDA also stated that openings to milk storage tanks and transfer pipes were not covered to prevent the entry of contaminants into the milk.