| 培养基名称 | EC肉汤，大肠杆菌肉汤，EC培养基 |
|---|---|
| 英文名称: |
EC Broth，E.coli Broth，EC Medium |
| 培养基类型: | 鉴别培养基 |
| 产品目录号: | M247-02 |
| 产品规格: |
500g 其它规格请联系我们 |
| 保存条件: | 密封，阴凉干燥处保存。制备好的培养基2-8°C避光保存。 |
| 产品性状: |
麦秸色粉末。 琥珀色透明液体。 |
| 注意事项: | 避免摄入、呼入、皮肤接触。配制时在通风橱中进行，戴口罩、手套、护目镜。 |
| 相关产品: | 十二烷基硫酸盐胰蛋白示肉汤 |
产品描述：
EC培养基（EC Broth）是选择性液体培养基，用于增菌和检测食品和环境中的粪大肠菌群。
本产品配方采用《细菌学分析手册》、APHA、FDA规定的标准配方。
EC肉汤培养基工作原理
大肠菌群是革兰氏阴性杆菌，能够快速发酵乳糖产气（水不溶性气体）。更为准确的定义是35°C条件下能够在LST培养基和BGLB培养基中生长，并且发酵乳糖产气的革兰氏阴性杆菌。在44.5°C条件下，24-48h内，还能够在EC肉汤中发酵乳糖产气的属于大肠菌群的一个子集——粪大肠菌群，发酵乳糖产酸产气的是大肠埃希氏菌。
胰蛋白月示提供大肠菌群生长所需营养物质。胆盐是革兰氏阳性球菌和产芽孢菌抑制剂，尤其是粪链球菌和芽孢杆菌。乳糖是大肠菌可发酵糖类。磷酸盐是pH缓冲系统，与氯化钠一起可以通过减慢乳糖发酵微生物生长速度来改善产气量。
EC培养基的用途：
EC肉汤培养基用于增菌和检测食品和环境中的大肠菌群。
EC肉汤培养基用于鉴别粪肠菌群。
EC肉汤培养基用于大肠杆菌E.coli的验证试验。
EC肉汤培养基也适合用于MNP法增菌牛奶和奶制品中的大肠杆菌。
EC培养基配方与配制方法
| 培养基成分： | 含量：/L |
|---|---|
| 胰蛋白示 | 20.0 g |
| 乳糖 | 5.0 g |
| K2HPO4 | 4.0 g |
| KH2PO4 | 1.5 g |
| NaCl | 5.0 g |
| 胆盐3号 | 1.5 g |
| 终溶液pH | 6.9 ± 0.2 |
配制方法：
1. 称取37.0g本品，加水1L去离子水溶解。
2. 分装8ml培养基到16x150mm试管中，确保液面没过倒置的10×75mm德拉姆发酵管。
3. 121°C高温蒸汽灭菌15min。
实验方法
1. Milk and Milk Products/Presumptive E. coli2 (ISO)
Tubes containing inverted Durham tubes with single and double strength Lauryl Tryptose Broth are inoculated with samples as described in the standard method. Incubate at 37°C for 24-48 hours and examine for gas production. Inoculate tubes showing gas production into a new series of tubes containing 10ml of EC Broth containing inverted Durham tubes, and incubate at 44°C for 24-48 hours. Transfer an inoculum from tubes giving rise to gas formation to tubes containing Tryptone Water , and incubate for 24-48 hours at 44°C. Examine for indole production and calculate the Most Probable Number (MPN) of presumptive E. coli. For full details please refer to the ISO Standard Method.
2. Faecal Coliform Test (APHA)
For differentiation of faecal coliforms inoculate EC Broth fermentation tubes containing inverted Durham tubes, and incubate in a water bath at 44.5°C for 24 ± 2°C hours. Gas production and growth within 24 hours or less is considered a positive faecal coliform reaction. For full details please refer to the APHA Standard Method3.
3. Confirmatory Test for E. coli (FDA/BAM)
From each gassing Lauryl Tryptose Broth tube, transfer a loopful of suspension to EC Broth tubes containing inverted Durham tubes. Incubate at 45.5°C, and examine for gas production after 24 and 48 hours. Gassing tubes are streaked onto EMB Agar and incubated at 35°C for 18-24 hours. Transfer 2 suspicious colonies from each plate onto PCA ,incubate fot 18-24 hours at 35°C and confirm with morphological and biochemical tests. For full details please refer to the FDA/BAM Standard Method4.
结果与分析
45.5±0.2°C（食品样本）或44.5±0.2°C（饮用水和贝类样本）条件下，在24±2 h内培养基变浑浊并且发酵管中出现气泡的视为粪大肠菌群。35±2°C条件下，在24±2 h内培养基变浑浊并且发酵管中出现气泡的视为大肠菌群。
标准菌株 生长情况 产气 大肠埃希氏菌 +++ + 肺炎克雷伯菌 +++ + 奇异变形杆菌 +++ - 绿脓杆菌 - - 枯草芽孢杆菌 - - 产气肠杆菌 - - 粪肠球菌 - -
