Enumeration of L. monocytogenes in positive samples is performed on reserve sample by colony count on L. monocytogenes differential selective agar in conjunction with MPN enumeration using selective enrichment in BLEB with subsequent plating on ALOA or BCM differential selective agar.
The major revisions to the Listeria methodology follow.
Certain prescribed rapid detection kits and their enrichments are now authorized screening alternatives to the standard selective enrichment.