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      簡述培養基制備的要求

      發布時間:

      2022-12-27

      作者:

      模擬灌裝用培養基


      使用脫水培養基和其他含有有害物質(膽鹽或其它選擇劑)的成分時,應遵守良好實驗室規范和生產廠商提供的使用說明配制。如質量/體積、pH、制備條件、滅菌條件和操作步驟等,并做好記錄。

      配制培養基使用蒸餾水或相同質量的水,以排除測試條件下抑制或影響微生物生長的物制。如果蒸餾水的用氯消毒的水制備的,在蒸餾前應先對氯進行中和(見GB/T6682)。盛放蒸餾水的容器最好是由中性材料制成的(如中性玻璃、聚乙烯等)。在初次使用前要確認容器中不含任何抑制因子。

      為保證蒸餾水的質量,電阻率應至少達到300000Ωcm。

      警告:采用離子交換器(去離子)生產的去離子水,微生物含量較高,這種水在過濾滅菌后仍可能帶有細菌生長的抑制因子。所以配置培養基時最好不要使用這種方法生產的去離子水而應使用蒸餾水。

      稱量和復水

      稱量所需的脫水培養基(注意緩慢操作,必要時佩帶口罩或在通風柜中操作,以防吸入含有毒物質的培養基粉末),先加入少量的水,充分混合(注意避免培養基結塊),然后再加入至所需的量。

      溶解

      脫水培養基加水后適當加熱,并不停攪拌使其快速溶解,必要時,重新溶解。含瓊脂的培養基在加熱前應先浸泡幾分鐘。用各別成分制備的培養基應將不同成分分別加入適量的水中,并充分溶解,然后再加入到所需的量。

      pH值的測定和調整

      用pH計測pH,必要時進行調整。在實驗室用各別成分制備培養基,除特殊說明外,培養基滅菌后冷卻到25℃時,pH的變化不應超過0.2個單位。一般使用濃度約為40g/L(約1mol/L)的氫氧化鈉溶液或濃度為36.5g/L(約1mol/L)的鹽酸溶液調整培養基的pH。

      注:商品化的培養基高壓滅菌后pH值可能變化很大,但采用優質蒸餾水或去離子水配配制時,滅菌前無需調節pH值。

      分裝

      將制配制好的培養基分裝到適當的容器中,根據不同用途,容器的體積可為培養基的1倍、2倍或3倍。

      滅菌

      培養基和試劑應采用濕熱滅菌或過濾滅菌。亮綠培養基等特定的培養基中含有對光和熱敏感的物質,只能煮沸滅菌。煮沸后應迅速冷卻,避光保存(參見相關標準或供應商使用說明)。

       

       


      The use of dehydrated medium and other ingredients containing harmful substances (bile salts or other alternatives) shall be subject to good laboratory specifications and instructions provided by the manufacturer. Such as quality/volume, pH, preparation conditions, sterilization conditions and operation steps, etc., and keep records.
      water
       
      The preparation medium USES distilled water or the same quality of water to eliminate or influence microbial growth under test conditions. If the distilled water is prepared by chlorine disinfection, the chlorine should be neutralized before distillation (see GB/T6682). Containers of distilled water are best made from neutral materials (such as neutral glass, polyethylene, etc.). Make sure the container does not contain any inhibiting factors prior to initial use.
       
      To ensure the quality of distilled water, resistivity should be at least 300000 Ω cm.
      Warning: ionized water produced by ion exchangers (deionized) is high in microbial content. This water may still contain the inhibitory factor of bacterial growth after filtration and sterilization. Therefore, it is best not to use this method to produce deionized water when the medium is used, and distilled water should be used.
      Weigh and rehydrate.
       
      Weighing the dehydrated medium (note that slow operation, wearing masks or in ventilation cabinet operation when necessary, to prevent inhalation of toxic medium powder), add a small amount of water first, mix (avoid medium agglomeration), then add to the amount required.
      dissolve
       
      After adding water to the dehydrated medium, heat it properly and do not stop stirring to dissolve it quickly. When necessary, redissolve it. AGAR AGAR medium should be soaked for a few minutes before heating. The culture medium prepared by each component should be added to the appropriate amount of water and dissolved, and then added to the desired amount.
       
      Determination and adjustment of pH value.
      PH meter is used to measure pH and adjust when necessary. Culture medium preparation from individual components in the lab, except where noted, culture medium after sterilization cooling to 25 ℃, the pH change should not be more than 0.2 units. The pH of the medium with a concentration of approximately 40g/L (about 1mol/L) or concentration of 36.5g/L (about 1mol/L) of hydrochloric acid solution was used.
      Note: the pH value may vary greatly after the commercialized medium high pressure sterilization, but the pH value should not be adjusted before sterilization with high quality distilled water or deionized water distribution.
      Partial shipments
       
      The prepared medium is divided into suitable containers, and the volume of the container can be 1, 2, or 3 times that of the medium according to different USES.
       
      sterilization
       
      The medium and reagent should be sterilized or sterilized by wet heat. A specific medium, such as a bright green medium, contains substances that are sensitive to light and heat, and can only be boiled and sterilized. After boiling, it should be cooled quickly to avoid light preservation (see related standards or supplier instructions).
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