filtration process in control of microorganisms.

Filtration:

It is the method of mechanical removal of microorganisms from liquid and gas substance. The filter of different techniques and nature have been developed. The efficiency of filtration depends upon the electronic nature of filters and kind of microorganisms to be filtered, the nature of fluid to be filtered etc. filtration is the mostly used for the sterilization of those fluid materials such as culture media which have been destroyed by different physical and chemical agents. In the case of microorganisms, pore size filter is used so that the microorganisms could not pass through the pores. usually, negative pressure is applied to the filter flask during the filtration of microorganisms carrying electric charge in order to speed up the faster filtration. Filtration is the best method for sterilization of heat sensitive liquids such as pharmaceutical drugs because as the other physical and chemical agents filtration does not inactive the drug. The most commonly used filters in the field of microbiology are described below:

• Membrane or molecular filter:

It is the filter of uniform porosity and made up of biologically inert cellulose esters. The size is predetermined and specific thickness is about 150um . The porosity may range from 0.01 to 10um. This filter is used extensively in lab and industry to sterilize fluid materials. The membrane filter is also used for identification and enumeration of microorganisms.from large volume suspension. The efficient filtration can be achieved by creating negative pressure with the use of water suction pump, vacuum etc.After filtration, the precaution must be taken to prevent the contamination.During the filtration process, the filter pad is washed to prevent the clogging by the microorganismsThis method is mostly used to sterilize heat liable fluids such as body fluids, antibiotics, enzymes and culture media. etc.

High-efficiency particulate air (HEPA):

It is a kind of filter used to screen microorganisms present in the air when air enters and exits from laboratory and industry. This type of filter with a system of laminar air flow is not used to produce such and bacteria face air. This method is mostly used for decontamination of air in the room. In the laminar flow, air moves only in one direction Become entering the air in the laminar flow it is initially filtered by HEPA filter and further the entered air is filtered so neither of microorganisms enters the chamber nor the air leaving the chamber consists any sign of microorganisms. It is mostly used in many microbiological laboratories to perform microbiological research works and particularly applied to handle dangerous pathogenic microorganisms.

Mechanical removal of microorganisms by ultrasonic and washing:

Ultrasonication is the method of removing microorganisms by the use of sound waves, washing of solid surface can be done to remove microorganisms or germs by using this method.

Application of physical agents:

References:

C.H.Collins. (1995). Microbiological Methods. Oxford Univ Press.

D.Greemwood, R. S. (2002). Medical Microbiology. London: Churchill Livingstone.

M.J.Pelezar. (1993). Microbiology. Tata McGraw hill.

M.T.Madigan, J. a. (1997). Biology of microorganisms. London: Prentice hall International Inc.

R.N.Atlas. (1984). Fundamentals and Applications. NewYork: MacMiHiam Publishing Co.