Why are petri dishes inverted when culturing microorganisms?
1. Slow down evaporation: Inverting the culture dish can slow down the evaporation of medium water in the culture dish;
2. Easy access: The lid of the petri dish is large and the bottom is small. If it is placed upright, it is easy to only take the lid when taking it, which will cause the exposure of the culture medium in the petri dish, which may cause contamination of the culture medium or drop of the petri dish.
3. Easy to observe: the petri dish is inverted, which can control the spread of colonies in the petri dish, which is conducive to the formation of single colonies and is convenient for experimental observation;
4. Avoid pollution: Inversion can prevent the water vapor in the petri dish from condensing on the lid of the dish and dripping onto the culture medium during the experiment, introducing bacteria into the culture medium, causing pollution and affecting the growth of microorganisms in the culture medium .
5. Convenient collection: Sometimes the goal of culture is to collect metabolites of bacteria. However, some metabolites are easily soluble in water. When the petri dish is placed on the cover, distilled water will appear, causing colonies to form flakes. Inverting the petri dish can facilitate the collection of metabolites , and counting or separation, etc.
6. Avoid cracking: In the forced ventilation incubator, you can use the method of inverting the culture dish to reduce the air flow on the surface of the medium and reduce the evaporation rate of the medium water, so that the medium is not easy to crack.
