Radiation:

We have discussed about the effects of radiation on the growth of microorganisms earlier. The radiations like ultraviolet and ionizing can be used for sterilizing objects. Ultraviolet radiation around 260 nm is quite lethal but does not penetrate glass, dirt films, water and other substances very effectively. UV radiation is used as a sterilizing agent only in a few specific situations, like UV lamps are placed on the ceilings of rooms or in biological safety cabinets to sterilize air and other exposed surfaces. Commercial UV units are available for water treatment. Pathogens and microorganisms are destroyed when a thin layer of water is passed under the lamps (water purifiers).

Ionizing radiation penetrates deep into objects and is an excellent sterilizing agent. It destroys bacterial endospores and vegetative cells of both prokaryotic and eukaryotic origin but not against viruses. Gamma radiation from a cobalt 60 source is used in the cold sterilization of antibiotics, hormones, sutures and plastic disposable supplies such as syringes, and Petri dishes.

 

REFERENCES:

Text Books:

1. Jeffery C. Pommerville. Alcamo's Fundamentals of Microbiology (Tenth Edition). Jones and Bartlett Student edition.

2. Gerard J. Tortora, Berdell R. Funke, Christine L. Case. Pearson - Microbiology: An Introduction. Benjamin Cummings.

Reference Books:

1. Lansing M. Prescott, John P. Harley and Donald A. Klein. Microbiology. Mc Graw Hill companies.