France, Aug. 13 -- French investigators are working to trace the source of a deadly listeria outbreak as pressure mounts over delays in recalling contaminated cheese.

Health authorities say 21 people have been infected and two have died, with tests pointing to a well-known cheese producer in central France.

The Chavegrand dairy, based in the Creuse department in central France and famed for its Camembert, creamy cheeses and goat's cheese, has recalled more than 40 batches of pasteurised cheese after tests suggested a link to the contamination.

According to national health agencySante Publique France and the Ministry of Agriculture, epidemiological and microbiological investigations carried out in early August revealed "converging evide...