Oxoid CM0862B 李斯特菌增菌肉汤 LISTERIA ENRICHMENT BROTH B.

Oxoid CM0862B 李斯特菌增菌肉汤 LISTERIA ENRICHMENT BROTH B.

OXOID 李斯特菌增菌肉汤

货号:CM0862B

规格:500g

品牌: OXOID

LISTERIA ENRICHMENT BROTH BASE

Code: CM0862

Typical Formula*

gm/litre

Tryptone soya broth

30.0

Yeast extract

6.0

pH 7.3 ± 0.2 @ 25°C
* Adjusted as required to meet performance standards

LISTERIA SELECTIVE ENRICHMENT SUPPLEMENT

李斯特菌选择性富集补充剂

Code: SR0141

Vial contents (each vial is sufficient for 500ml of medium)
per vial
per litre
Nalidixic acid

20.0mg

40.0mg
Cycloheximide

25.0mg

50.0mg
Acriflavine hydrochloride

7.5mg

15.0mg

Directions
Suspend 18g in 500ml of distilled water. Add the contents of one vial of Listeria Selective Enrichment Supplement (SR0141), reconstituted with 2ml of distilled water. Sterilize by autoclaving at 121°C for 15 minutes. Cool to 50°C, mix well and distribute into sterile containers in volumes as required.

LISTERIA SELECTIVE ENRICHMENT SUPPLEMENT (modified with 10 mg/litre of Acriflavine)

Code: SR0149.

Vial contents (each vial is sufficient for 2,250mls of medium)
per vial
per litre
Nalidixic acid

90.0mg

40.0mg
Cycloheximide

112.5mg

50.0mg
Acriflavine hydrochloride

22.5mg

10.0mg

Directions
Aseptically add 10ml of distilled water to one vial and invert gently to dissolve. Add the vial contents to 2.25 litres of Listeria Enrichment Broth Base. Sterilize by autoclaving at 121°C for 15 minutes. Cool to 50°C, mix well and distribute into sterile containers in volumes as required .

Description
Listeria Selective Enrichment Medium is based on the formulation described by Lovett et al.1 and is recommended for the selective enrichment of Listeria species from food. The enrichment procedure has been shown to recover an inoculum of less than 10 cfu/ml from raw milk.

In order to achieve a higher isolation rate it is recommended that the enrichment broth is subcultured onto Listeria Selective Agar plates after 1, 2 and 7 days. Agello et al.2, have shown that extending the incubation period to 7 days allows better recovery of environmentally stressed listeria from milk and milk products.

Technique
1. Add 25g or 25ml samples to 225ml of Listeria Selective Enrichment Broth. Homogenise if required.
2. Incubate at 30°C for 7 days.
3. Subculture from the Listeria Selective Enrichment Broth onto Listeria Selective Agar plates (see Note) after 1, 2 and 7 days by:
(i) Direct plating onto Listeria Selective Agar plates.
(ii) Adding 1ml of the Listeria Selective Enrichment Broth to 9ml of 0.5% KOH, vortex mixing, and plating onto Listeria Selective Agar plates.

Note:
Suitable Listeria Selective Media are:
1. Listeria Selective Medium (Oxford formulation) (Oxoid CM0856 and Oxoid SR0140).
2. PALCAM Medium (Oxoid CM0877 and Oxoid SR0150).

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium at 2-8°C.

Appearance
Dehydrated medium: Straw coloured, free-flowing powder
Prepared medium: Straw coloured solution

方向
在无菌条件下向一个小瓶中加入 10ml 蒸馏水并轻轻倒置以溶解。将小瓶内容物添加到 2.25 升李斯特菌浓缩肉汤基质中。通过在 121°C 高压灭菌 15 分钟进行灭菌。冷却至 50°C,充分混合并根据需要分装到无菌容器中。

描述
李斯特菌选择性富集培养基基于 Lovett 等人 1 描述的配方,推荐用于从食品中选择性富集李斯特菌。已显示富集程序可从原料奶中回收低于 10 cfu/ml 的接种物。

为了获得更高的分离率,建议在 1、2 和 7 天后将富集肉汤传代培养到李斯特菌选择性琼脂板上。 Agello 等人 2 表明,将潜伏期延长至 7 天可以更好地从牛奶和奶制品中恢复环境压力李斯特菌。

技术
1. 将 25g 或 25ml 样品加入 225ml 的李斯特菌选择性富集肉汤中。如果需要,均质化。
2. 30°C 孵育 7 天。
3. 1、2 和 7 天后,将李斯特菌选择性富集肉汤传代培养到李斯特菌选择性琼脂平板(见注)上:
(i) 直接铺板到李斯特菌选择性琼脂板上。
(ii) 将 1 毫升李斯特菌选择性富集肉汤加入 9 毫升 0.5% KOH 中,涡旋混合,然后铺板到李斯特菌选择性琼脂板上。

笔记:
合适的李斯特菌选择性培养基是:
1. 李斯特菌选择性培养基(牛津配方)(Oxoid CM0856 和 Oxoid SR0140)。
2. PALCAM 培养基(Oxoid CM0877 和 Oxoid SR0150)。

储存条件和保质期
将脱水培养基储存在 10-30°C 并在标签上的有效期之前使用。
将准备好的培养基储存在 2-8°C。

外貌
脱水介质:稻草色、自由流动的粉末
制备培养基:稻草色溶液

Quality control

Positive control: Expected results
Listeria monocytogenes ATCC® 7644 * Turbid growth
Negative control:
Enterococcus feacalis ATCC® 29212 * Inhibited
* This organism is available as a Culti-Loop®

Precautions
Note the precautions stated under Listeria Selective Medium (Oxford) CM0856 and SR0140. Broth cultures are more dangerous than colonies on agar plates.
Store prepared medium away from light. Acriflavine can photo-oxidise to form inhibitory compounds against Listeria.
Supplement SR0141 used in this medium contains a toxic concentration of cycloheximide. Note the precautions to be taken under HAZARDS.

References
1. Lovett J., Francis D. W. and Hunt J. M. (1987) Journal of Food Protection 50. 188-192.
2. Agello G., Hayes P. and Feeley J. (1986) Abstracts of the Annual Meeting, ASM, Washington DC p5.

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