I believe everyone often needs to flip the tablet during the experiment, right? Beginners often struggle, leading to problems in subsequent experiments. Here are a few tips for your reference:
Pouring temperature of culture medium
1. The suitable temperature for pouring the culture medium is about 45 ℃. When the culture medium is placed in the palm of the hand, it does not feel hot, but when placed on the back of the hand, it feels hot, and the temperature of the culture medium is about 45 ℃. If the temperature is too high during the pouring of the culture medium, the solidification time will be longer, and there will be a large amount of condensed water on the lid of the dish, which is not conducive to subsequent experiments. If the temperature is too low, it is easy to experience partial solidification of the culture medium in the bottle during the flipping process.
2. Some culture media require the addition of additives, which should be placed at room temperature before addition to avoid cold liquids causing agar to coagulate or form flakes.
3. At present, most laboratory culture media are placed in a water bath or oven after sterilization, and when needed, they are taken out and directly flipped. However, the culture medium should not be left standing for too long, and the standing time should generally not exceed 4 hours. If left standing for too long, the agar in the culture medium may solidify slightly, forming a flocculent precipitate.
4. During the experiment, it is inevitable that due to special circumstances, the culture medium that has not been inverted may have solidified. After solidification, the culture medium can be reheated and dissolved. Generally speaking, boiling water bath or induction cooker heating cannot sterilize the bacteria again.
The general pouring amount of the tablet is around 18-20ml. If the cultivation time exceeds 48 hours or the cultivation temperature is higher than 40 ℃, in order to prevent excessive evaporation of water from causing the tablet to open, the pouring amount is generally around 25ml. Some culture dishes may have a scale, pour according to the scale.
Bubbles are prone to occur during the flipping process, especially in culture media such as BS agar that require shaking well before flipping. If there are too many bubbles, it will affect the observation of the results. When pouring the plate, try to pour it in slowly and leave the bubbles at the bottom of the bottle. If there are a small amount of bubbles in the plate, you can shake the bubbles onto the wall of the plate, which will not affect the observation of the results.
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