Question

Discuss the technique of filtration as a microbial control method, why it's utilized, and specific materials that are filtered.

Answer 1

Filteration is the technique to minimize the microbial population population in a solution .Air/Water is filtered through High Efficiency Particulate (HEP) filters .They have effective pore size of 0.3 micrometer ,small enough to capture bacterias, endospores etc. as air passes through these filters ,nearly sterlilzing the air/water on the other side of the filter . The standard bacteriological filters are made up of porous membrane of cellulose acetate,cellulose nitrate ,polycarbonate or other synthetic material having pores.Membrane with pore size about 0.2 pm in diameter are used to remove most vegetative cells but not viruses from solution ..These filters are used to sterilize pharmaceuticals ,opthalmic solutions and other heat sensitive solutions.Microorganisms such as bacteria and algae ,yeast and moulds can be separated from the fluids ,but viruses and mycoplasma cannot be eliminated .It is never possible that filteration procedure that renders a solution of bacterium free will also be free from viruses .The advantages of filteration are:-

a) Absolute sterilization -separates particle based on ionic size .

b) Removal of multiple particle size .

c) Allows for fairly high throughout.

d) Used for heat sensitive media .

The disadvantages of filteration are :-

a)Each filter has a specific nominal pore size .

b)May require a high differential pressure.

This technique is utilized as some fluids would be damaged by heat,radiation or through chemical sterilization .So to avoid damage ,filteration as a microbial control method is preferred.

The specific materials that it filters are fungi,bacteria ,endospores ,unicellular eukaryotes etc.