| 產品名稱: | 氯硝胺甘油瓊脂培養基、DG18瓊脂基礎、氯硝胺甘油培養基 |
|---|---|
| 英文名稱: |
Dichloran Glycerol Agar Base DG-18 Agar Base |
| 培養基類型: | 選擇性培養基 |
| 產品目錄號: | M306-01 |
| 產品規格: |
500g 其它規格請聯系我們 |
| 保存條件: | 密封，陰涼干燥處保存。 |
| 產品性狀: |
稻草色粉末，易吸潮。 |
| 注意事項: |
有毒！避免攝入、呼入、皮膚接觸。 對胎兒有潛在毒性 。有潛在致癌性。 配制時在通風櫥中進行，戴口罩、手套、護目鏡。 |
| 相關產品: | RV肉湯培養基 |
產品描述：
氯硝胺甘油瓊脂培養基（DG-18 Agar）也稱DG18瓊脂，是低水活度培養基，用于干和半干食品中霉菌計數。
原理：
甘油的添加可以降低培養基的水活度Aw至0.95左右，低水活度可以抑制大部分細菌的生長。氯硝胺可以抑制毛霉屬真菌的擴散，限制其它屬的菌落大小。這種限制性特征，使得平時生長較小的菌落變得容易觀察，因此DG18培養基尤其適合用于霉菌計數。另有文獻報道，將Triton-X添加到DG18培養基中會近一步抑制迅速擴散的真菌。
氯硝胺甘油培養基的用途
DG18培養基用于酵母和霉菌的分離和培養。
DG18培養基用于從干或半干食品中分離嗜干霉菌。
DG18培養基用于干果、香料、甜食、麥片、堅果、肉干、魚干等食品的檢測。
DG18培養基的配方與配制方法
蛋白胨 .....................5.0 g 葡萄糖 .....................10.0 g 磷酸二氫鉀 .................1.0 g 硫酸鎂 .....................0.5 g 氯硝胺 .....................0.002 g 瓊脂粉 .....................15.0 g 配制方法： 1. 稱取本品31.6g，用超純水定容至1000 mL,煮沸1分鐘至完全溶解。加入220g甘油。 2. 121度高溫蒸汽滅菌15分鐘。不要過度加熱！ 3. 待培養基冷卻至55度左右時，加入金霉素5mL（10mg/mL）或2mL（25mg/mL）氯霉素。
實驗方法
PURPOSE:
Identification of culturable microorganisms and assessment of possible proliferation and dissemination of bacteria or fungi from building reservoirs.
FIELD
EQUIPMENT:
1. Samplers:
a. Andersen 2-stage cascade impactor, or equivalent, for fungi and mesophilic bacteria.
b. Andersen N-6 single-stage sampler, or equivalent, for thermophilic actinomycetes.
2. Sampling media, in plates prepared according to sampler manufacturer’s recommendations:
a. Malt extract agar (MEA) for fungi.
b. Trypticase soy agar (TSA) for mesophilic bacteria and thermophilic actinomycetes.
NOTE: Other media may be used, if appropriate, e.g., dichloran glycerol agar (DG18) for xerophilic molds, R2A agar for heterotrophic bacteria, and rose bengal agar for slowgrowing fungi such as Stachybotrys.
3. Sampling pump capable of meeting sampler manufacturer’s flow specification (e.g., 28.3 L/ min), with flexible connecting tubing.
4. Cotton gauze pad, e.g., 4” × 4”.
5. Rubbing alcohol, 70% isopropanol.
6. Refrigerant packs, if necessary for keeping samples cool during shipment.
NOTE: Keep samples cool, but protect from freezing.
SAMPLING
STRATEGY:
1. Select at least three sites, one each to represent complaint area, a noncomplaint area (otherwise as similar as possible to complaint area), and outdoors.
2. In turn at each site, sample simultaneously for fungi, mesophilic bacteria, and thermophilic actinomycetes. Typical sampling time is ten minutes. Before moving to the next site, repeat twice to obtain triplicate, consecutive samples.
3. Load and immediately unload one set of sampling media in each sampler to serve as field blanks.
4. Collect another complete set of samples and blanks on the next day.
SAMPLING:
1. Calibrate each sampling pump with a representative sampler in line.
2. Before each run, carefully and thoroughly wipe each sampler stage with rubbing alcohol. Allow to dry. Make sure air passages are not blocked.
3. Load sampling media into sampler, remove covers from media, and attach sampler to pump with flexible tubing.
NOTE: Take special care to prevent contamination of media during loading and unloading. Do not touch agar surface.
4. Sample at known preset flow for an accurately known time, e.g., 10 min. (In heavily contaminated areas, a shorter sampling time may be necessary.)
5. Replace covers on sampling media, unload, and pack securely for shipment (plates should be media side up).
SHIPPING:
Keep collected samples and blanks cool (not necessarily ice-cold) and ship as quickly as possible to a laboratory for enumeration and identification.
ANALYSIS:
Mesophilic bacteria and thermophilic actinomycetes are usually identified to species and fungi usually identified to genus. Interpretation is subjective and based on total numbers and rank order of taxa in complaint area compared with control areas (noncomplaint and outdoors).