In microbiology, medium in microbiology is a mixture of nutrients that microorganisms use for growth, reproduction, and metabolism. Because microorganisms require different types of nutrients and have varying nutritional requirements, as well as for various research purposes, many different types of medium and raw materials are utilized. A sufficient PH, a particular buffering capacity, a certain redox potential, and a suitable osmotic pressure should also be present in the medium. The medium must be produced and sterilised in order to suit the study's unique requirements, therefore how should medium in microbiology be prepared and sterilised?
1. Prepare the medium in the microbiology solution
Add a portion of the required water to the container, weigh the various raw materials according to the medium's formula, add them to dissolve them, and then add the remaining water. Peptone, meat paste, and other substances must be heated to dissolve, and the water evaporated during the heating process should be added after all the raw materials have been dissolved.
When making solid medium in microbiology, boil the above-mentioned liquid medium first, then add the weighted agar and continue heating until it is completely melted, stirring constantly to prevent the agar paste from burning.
2. The PH of the medium in microbiology is adjusted
If the PH of the medium does not satisfy the requirements, modify it with 10 percent HCl or 10 percent NaOH until it meets the recipe's requirements.
3. There is a filter medium in microbiology
While the prepared medium is still hot, filter it with filter paper, gauze, or cotton. If you're using gauze, fold it into six layers, and if you're using filter paper, fold it into a waffle form and place it on a funnel to filter.
4. Split the medium in microbiology
It's a good idea to segregate the filtered media. The media must be separated into test tubes if slant media is to be made. The media must be separated into conical flasks if you wish to manufacture flat media, liquid or semi-solid media. Squeeze the spring clip loosely with one hand to let the microbiological media flow out, and with the other hand, hold numerous tubes or conical flasks and pick up the medium one at a time. To avoid contamination from wet cotton plugs, avoid allowing the medium to stick to the opening of the tube or bottle when dispensing. The amount of medium loaded into the tubes is determined by the tubes' and conical flasks' size and demands. General slanting medium production, each 15 150 mm test tube approximately 3 4 ml (1/4 1/3 test tube height), such as deep medium production, each 20 220 mm test tube about 12 15 ml. Half of the contents of each conical flask is usually filled with medium.
5. Medium in microbiology with cotton plugs
The mouth of the tube or bottle must be sealed with a cotton stopper after dispensing. The cotton stopper's principal purpose is to filter the air and prevent infection. Cotton plugs should be produced from fresh, dry cotton, not scraped cotton, since water absorption may render the plugs ineffective. When making cotton plugs, spread the cotton to the appropriate thickness for the plug's size, then place a palm-sized piece in the circular hole made by the left thumb and index finger, insert the middle of the cotton with the right index finger, and hold it slightly with the left index finger and thumb to form a long stick-shaped cotton plug. To avoid the invasion of airborne microbes along the folds, the cotton stopper should be put into the mouth of the tube or bottle as soon as possible after it is created, and the stopper should be snug against the inner wall without leaving a gap. After plugging, the cotton stopper should not be too tight or too loose; otherwise, the tube, bottle, and cotton stopper will not fall as intended. 2/3 of the stopper should be within the tube or bottle, with a small amount of cotton showing on the upper end for easy extraction. In preparation for sterilisation, thick paper should be wrapped around the stoppered tubes and conical bottles and fastened with twine.
6. Making slant media and plates in medium in microbiology
The creation of slant and plate media must be done when the medium is still hardened after sterilisation in microbiology.
(1) Create a slanting media. Place a 0.5 to 1 m long hardwood strip on the laboratory table, with a thickness of about 1 cm, so that the culture medium within the test tube is naturally inclined, formed into a sloping medium in microbiology.
(2) Prepare a medium-sized plate. Simply place the conical flask with medium and petri dishes on the laboratory bench, light the alcohol lamp, use the right hand to hold up the bottom of the flask, the left hand to pull off the cotton plug, the mouth of the bottle in the alcohol lamp slightly burned, the left hand to open the Petri dish cover, and the right hand to quickly pour the medium into the Petri dish, each dish about 10 ml, to spread the bottom of the dish as degree. After laying the medium for about 15 minutes, wait for it to solidify, then stack 5 petri dishes in a stack, invert them, and place them flat in the thermostat for 24 hours to see if they can be used to cultivate microorganisms, such as the media at the end of the lengthy miscellaneous bacteria.