PARIS -- French investigators were searching the headquarters of dairy giant Lactalis on Wednesday as part of an investigation over salmonella contamination that affected scores of infants and triggered an international recall, state-run radio reported.

Gendarmes and officers from the National Investigation Service of the Directorate-General for Competition, Consumer Affairs and Fraud Control (DGCCRF) raided also four other sites of the French company, including factory in Craon, northwest France where the milk had been tainted, France info said.

The search is part of an inquiry opened last month by the health division of Paris prosecutor office for "involuntary injuries", "putting in danger of the life of others", "non-performance of recall procedure."

"As we have indicated, Lactalis puts itself at the disposal of the justice and will bring all the elements necessary for the good progress of the investigation," Michel Nalet, Lactalis spokesman was quoted as saying by local media.

Thirty-five infants in France, who had consumed infant milk products manufactured by Lactalis' factory in Craon have been confirmed with salmonella infection during the last few months.

The food safety affair worsened after France's retailers including Carrefour, Auchan and Leclerc admitted they sold the products recalled in December.

The salmonella scare had forced the family-owned dairy group, one of the world's leading dairies to recall more than 12 million tins of baby milk.