US poultry producer Pilgrim’s Pride knew that the listeria bacteria was present at its Pennsylvania plant months before its products were linked to a listeria outbreak that caused at least seven deaths and over 40 cases of illness, according to a federal meat inspector.

Vincent Erthal, a federal meat inspector for the night shift at Pilgrim’s Pride’s Wampler facility until September, said the company had found an “exceedingly high” number of the harmful bacteria in the plant months before the October recall. Erthal also alleged that the USDA inspector in charge, Debra Martin, knew of the listeria problem at least four months before the recall. USDA officials have, however, denied Erthal’s allegations, saying inspectors were not aware of a listeria problem at the Wampler plant until late September.

USDA Undersecretary Elsa Murano said Pilgrim’s Pride employees had routinely tested for listeria and found “a spike” in July and August for its presence, reported Reuters. The company did not share the information with the USDA because federal regulations do not require companies to test for listeria. Murano said the USDA only found out about the tests in late September when an investigation was carried out.

Wampler said in defence that it had tested for listeria since 1999 and has always shared its results with USDA inspectors.

“We routinely provide our environmental test results – both positive and negative – for USDA’s review,” David Van Hoose, chief executive officer of Wampler, was reported as saying by Reuters. “USDA inspectors, including Vince Erthal and the inspector in charge, Debra Martin, were periodically seen reviewing records… indicating to us that they certainly were familiar with the records we maintained for them and for their review.”