称取本品 71.9g,加热搅拌溶解于 1000ml 蒸馏水中,分装三角瓶,每瓶 200ml, 121℃高压灭菌15分钟,冷至 50℃左右时,加入 1 套 PALCAM 琼脂添加剂( 添加剂 1 和添加剂 2 ),混匀倾入无菌平皿。
PALCAM添加剂
李斯特菌鉴别琼脂别名是PALCAM 琼脂吗实验方法
Techniques for the isolation of Listeria monocytogenes will depend on the material under test. It is usual for the test sample to be first inoculated into an enrichment broth to allow multiplication before isolation and identification. Depending on the type of sample used, the appropriate method and selective enrichment broth should be used prior to inoculation onto PALCAM Medium plates. As a general rule, use Listeria Selective Enrichment Medium for dairy products, and Listeria Selective Enrichment Media UVM and Fraser Broth for meats and poultry.
1.Inoculate one loopful of the selective enrichment broth onto the PALCAM Medium plates.
2.Incubate at 37°C for 48 hours under micro-aerophilic conditions.
3.Examine for typical colonies of Listeria after 48 hours incubation.
4.Colonies identified as presumptive Listeria spp. must be confirmed by biochemical and serological testing.
After 48 hours incubation, typical Listeria spp. form colonies that are approximately 2mm in diameter, grey-green in colour with a black sunken centre and a black halo against a cherry-red medium background. Occasional enterococci or staphylococci develop on PALCAM Medium to forming grey colonies with a brown-green halo or yellow colonies with a yellow halo.