Preparation Of Temporary Cotton Plugs 

Microorganisms are everywhere in their the distribution. In any given environment, many microorganisms are present at any given time. It is difficult to identify a specific kind of microbe until we understand their ecological needs. For instance, anaerobic microbes do not require oxygen those that are aerobic require oxygen micro-aerophiles to have oxygen however, in a small amount. So, we require cotton plugs to provide an conditions that are aerobic and keep the growing culture uninvolved with unwanted microbes. Cotton plugs are made of cotton along with air pours. Air can flow through air pours, but not the bacteria that cause microbial contamination. They are fixed to the surface of cotton fibres , and prevent them from being able from getting into flasks, tubes, etc. Air aids in for the development of microorganisms within glass equipment.

Requirements

• Non-absorbent cotton rolls
• Culture tubes
• Flasks
• Scissors

Procedure

1. Get a non-absorbent cotton roll and then remove the packing
2. Roll up the roll according to the requirements (i.e. size, number and type)
3. Cut a small amount of cotton using scissors. In accordance with the specifications, the two varieties of cotton plugs can be made.

A. Cut, fold and rolled plug

1. Cut a small portion of cotton sheets using scissors according to the requirements i.e. flask/ culture tube, etc.
2. Fold the cut piece away from the center.
3. Fold the sheet starting from one of its ends. The opposite side, cotton fibres are released freely.
4. Inject the rolled and folded side into the neck or mouth of a flask/culture tube and the opposite end of the plug is covered with cotton fibres.
5. If it’s not tight, remove the cap and remove the cotton from one side and then adjust as before.

B. Cut, rolled and fold plug

1. Cut the appropriate cotton with the aid of scissors.
2. The piece is rolled from one end to the other
3. Remove the rolled piece away from the middle.
4. Place the folded end into the mouth/neck of the flask/culture tube and the other with cotton fibres is positioned in the air.

Preparation Of Permanent Cotton Plugs

Temporary cotton plugs made in the above manner are not recommended for use repeatedly since they can be contaminated by microorganisms due the adhesion to growth media. To avoid the need to prepare plugs of cotton more often permanent plugs must be made.

Requirements

• Same as described for temporary cotton plug
• Muslin cloth

Procedure

1. Make temporary cotton plugs according to the procedure previously described.
2. Cut small squares (4-6″) from the muslin cloth.
3. Place the folded edge of the plug into the middle in a piece muslin cloth
4. Securely tie all four edges of the muslin at the unrolled free end on the plug. It’s a durable cotton plug that is reusable.