Isolation and identification of L. monocytogenes. Samples (25 g) were blended in 5 to 10 ml of sterile distilled water by a stomacher and added to enrichment media (11). L. mono- cytogenes was isolated with or without alkaline treatment on
LiCl-phenylethanol-moxalactam agar and identified by bio- chemical, motility, and CAMP tests (11). The suspected isolates were also identified by the API 20 Strep test (API System, Montalieu Vercieu, France).