Selective plating medium for quantitative recovery of food-borne Listeria monocytogenes.
A new plating medium (lithium chloride-ceftazidime agar [LCA]) was designed to quantitatively recover food-borne Listeria monocytogenes in the form of large colonies while inhibiting most other food-borne microorganisms. This medium included brain heart infusion agar as the nutritive agar base and a combination of selective agents (LiCl, glycine anhydride, and ceftazidime). Comparison of LCA and lithium chloride-phenylethanol-moxalactam agar (LPM) indicated that both were equally effective for the enumeration of the cold-tolerant pathogen in artificially and naturally contaminated foods. However, LCA was more effective than LPM in the recovery of sublethally heat-injured cells. Moreover, Listeria colonies on LCA exhibited a more distinct bluish hue than those on LPM when viewed by the Henry oblique transillumination technique.
Lachica
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U.S. Army Natick Research, Development and Engineering Center, Massachusetts 01760.
D003470:Culture Media; D005506:Food Contamination; D005516:Food Microbiology; D006358:Hot Temperature; D008089:Listeria monocytogenes / Q000254:growth & development* / Q000302:isolation & purification; D008460:Meat; D008461:Meat Products
D003470:Culture Media