Recovery of 15 pure strains was tested in the prestudy and recovery of one strain from foodstuffs was tested in the collaborative trial. Results from the prestudy did reveal statistical difference of the media but recoveries on all media were within the microbiological limits (F 30%) of IS, which was set as a reference medium. Recoveries on the media tested in the collaborative trial were statistically different as well, but these differences were of no microbiological–analytical relevance.