Description
The method is intended for the detection of Listeria monocytogenes in foods and feedstuffs and for the enumeration of L. monocytogenes in foods. The method describes both the detection and the enumeration procedure of L. monocytogenes. In the detection procedure, two-step enrichment is used. The primary enrichment is carried out in an enrichment broth with reduced selectivity (Half-Fraser broth) at 30 C for 24 h. In the enumeration procedure, the initial suspension and/or its dilutions, carried out either in Saline peptone water (SPW), Buffered peptone water (BPW) or base medium for Half-Fraser broth, are surface plated on a L. monocytogenes specific isolation medium, ALOA, LCA or LMBA or chromogenic Listeria Agar with equal operating principle as ALOA.
This NMKL method has been validated in a collaborative study.