Sterility Testing of Glass Wares

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BACKGROUND

Sterility testing is a testing that confirms that the products are free from the presence of microorganisms. It is important for medical devices, pharmacy preparations, and other materials. It is a qualitative test that shows the quality of the samples tested. It is testing that should be carried out by trained persons.

So the objective of the test is to carry the sterility testing for glass wares.

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REQUIREMENTS

 

Apparatus:            Glasswares

        Surgical instruments

        Test tube

        Glass syringes

        Pipettes

        Flasks

        Petridishes

Scissors

   Forceps

Instruments:        Hot air oven

       Autoclave

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PROCEDURE

Basically following methods are adapted for sterilization.

• Dry heating : Hot Air Oven
  
• Moist heating: Autoclave
  

Dry heating

Dry heating tends to kill microbes by oxidation of cellular components. This requires more energy, so higher temperature is required for efficient sterilization. So the instrument used for dry heating is Hot Air Oven. This is widely used for sterilization by dry heat. Hot Air Oven was originally developed by Pasteur.¹ The main benefit of this oven is they do not require water and there is not much pressure build up for sterilization. Hot Air Oven works in a manner that the items kept for sterilization doesn’t get fire or melt down even in such high temperature. Temperature maintained is between 160-170^oC and the time taken is 1 h for sterilization. But before sterilization glass wares are pre washed with apyrogenic water. They sterilize almost all the glasswares needed in the laboratory such as scissors, petridishes, forceps, pipettes, test tubes, flasks, glass syringes and many more,

Moist heating

This method of sterilization uses pressurized steam to heat the material to be sterilised. This is a very effective method that kills all microbes’ spores, viruses. The instrument used for this type of heating is Autoclave invented by Charles Chamberland in 1884, although a precursor known as steam digester was created by Denis Papin in 1679.^2,3 Autoclave kills microbes by hydrolysis and coagulation of cellular proteins which is efficiently achieved by intense heat in the presence of water. This intense heat comes from the pressurised steam. Autoclaves used to sterilize laboratory apparatus {petridishes, test tubes, flasks, glass syringes}, medias, cotton swabs by subjecting them to high pressure (15 lbs) steam at 121^oC for around 15-20 minutes.⁴

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CONCLUSION

Thus the sterility testing of glass wares are carried out by some of the above given methods.

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REFERENCES

1. Ananthanarayan R, Paniker C.J. Textbook of Microbiology, India (7^th Edition). 2006: 2, 25-26.
   
2. Chamberland C. Chronological reference marks-Charles Chamberland (1851-1908); Pasteur Institute”. 2006.
   
3. Hugo WB. Ábrief history of heat and chemical preservation and disinfection. J Appl. Bacteriol” 1991: 71(1): 9-18.
4. Black J. “Microbiology: Prentice hall”. 1993: 334.