French dairy group Lactalis, which is facing a growing scandal over salmonella-tainted baby milk, did not report the bacteria had been found on products in the same factory in 2011 despite an obligation to do so, a government official said.
Dozens of babies fell ill after drinking baby milk contaminated with so-called Salmonella Agona produced by Lactalis, one of the world's largest dairy groups, prompting the recall of 12 million tins.
"There has been a lag between elements given to inspection services and the self-checks that we have been able to recover as part of the crisis," the head of the French government's food department, Patrick Dehaumont, told a Senate commission.
"Salmonella Agona had been found in 2009, 2014, one on products in 2011 and other serotype in 2013 and 2014," he added.
Lactalis Chief Executive Emmanuel Besnier said earlier this month in an interview that Salmonella Agona had been found in the environment between 2005 and 2017, so it could not be excluded that babies had consumed contaminated milk over that period.
The company had made no public reference to positive tests on products.
Lactalis spokesman Michel Nalet declined to comment.
Companies in France must report to the authorities tests that show salmonella in a product. They are under no obligation to do so for tests showing the bacteria in the environment but must provide the results if asked to do so.
Asked to confirm that positive Lactalis self-checks had not been handed to the authorities, he replied: "That's it".
"What's unfortunate, is that there was no questioning by the company about the fact that it was still amazing to find a Salmonella Agona several times over the years after it was found in 2005," Dehaumont said.
More than 200 babies in France have been contaminated with Salmonella Agona since 2005, including 38 between mid-August and December last year, as well as 25 between 2006 and 2017 and 141 in 2005, said the Institut Pasteur, a French organisation that monitors micro-organisms and diseases.