Any one of the media evaluated can interchangeably be used as an obligatory isolation medium for the detection and enumeration of L. monocytogenes in foods, and for the detection in feed-stuffs. The L. monocytogenes specific plating media that were evaluated shorten the time of analysis and significantly reduce the work load. The detection of positive samples mostly after Half-Fraser enrichment, reduces the analysis time further, and makes it possible to skip the secondary enrichment. However, secondary enrichment cannot be totally left out, because samples with low levels of L. monocytogenes, with high levels of competing flora, and with injured L. monocytogenes, do need secondary enrichment.
