what is Microbial control? what are the uses of Microbial control? types of Microbial control?

The process of making sterile.the killing of all forms of life.                         


An agent that frees from injection by killing the vegetative cell of microorganisms.


 acting against {or} opposing sepsis, faction {or} decay by either preventing {or} arresting the growth of organisms.



the process of destroying all forms of microbial life. A sterile object in the microbiological sense is free of living microorganisms.
 the term sterile, sterilize and sterilization therefore refer to the complete absence of {or} destruction of all microorganisms and should not be used in a relative sense.
An object {or} substance is sterile {or} non sterile it can never be sterile are almost sterile


An agent as usually a chemical that kills the growing forms but not necessarily the resistant spare forms of disease producing microorganisms the term is commonly applied to substance used inanimate objects disinfection is the process of destroying infectious agent.


a substance that opposes species that have prevent the growth or action of microorganisms are there by destroying microorganisms or by inhibiting their growth and metabolism as usually associated with the substances applied to the body.


an agent that reduces the microbial population to safe levels as judge by public health requirements usually it is a chemical agent that kills 99.9 percent of the growing bacteria sanitizers are commonly applied to inanimate objects and are generally employed in the daily care of equipment and utilzes in diaries food plants and for glasses.


An agent that kills the growing forms but not necessarily the resistance spore forms of gems in practice is germicide is almost the same thing as a disinfectant but germicide are commonly used to for all kinds of gems for any applications.


An agent that kills bacteria similarly the terms fungicide, virucide and sporicide referred to agent that kills fungi, virus and spores respectively.


A condition in which the growth of bacteria is prevented similarly fungistatic describes an agent that stops the growth of fungi agents that have in common the ability to inhibit the growth of microorganisms are collectively designated microbiostatic agent.

Antimicrobial agent :-

one that interferes with the growth and metabolism of microbes in common uses the terms denotes inhibition of growth and with reference to specific groups of organisms such term as antibacterial are frequently employed. Some antimicrobial agents are used to treat infections and they are called chemotherapeutic agents.


Moist heat:- the application of moist heat for inhibiting or destroying microorganisms.


Heat in the form of saturated steam under pressure is the most particular and dependable agent for sterilization.
The laboratory apparatus designed to use steam under regulated pressure is called an autoclave.
It is essentially a double jacketed steam chamber to be filled with saturated steam.
The autoclave is an essential unit of equipment in every microbiology laboratory.
Many media solutions discarded cultures and contaminated materials are routinely sterilized.
The autoclave is operated at a pressure 15 lb [1210 c]the time of operation to achieve sterility depends on the nature of the materials being sterilized.

Dry heat:-

Hot air sterilization:-

Dry heat sterilization is recommended where it is either undesirable.
In this laboratory glassware petridishes as well as oils for orders powders.
For glassware 2 hours exposure to a temperature of 100oc is sufficient for sterilization.


Destruction of microorganisms by burning is practised routinely in lab.
When the transfer needle is introduced into the flame of the bunsen burner.
 incineration is used for destruction of infected laboratory animals and other injected materials to be disposed off.


Desiccation of the microbial cell causes is the cessation of metabolic activity followed by a decline in the total viable population.
Species of grand negative cocci such as gonococci are very sensitive desiccation they die in a matter of  hours.
Streptococci are much more resistant survival, survive weeks after being dried.
Dried spores of microorganisms are known to remain viable.

Surface tension:-

The interference or boundary between a liquid and a gas is characterized by unbalanced forces of attraction between the molecules in the surface of the liquid in the interior.
A molecular at the surface of the liquid air interference is pulled strongly towards the interior of the liquid beneath it.
Surface forces also exist between two immisible liquid under the interference between the solid and liquid they are referred as interfacial tension.

Osmotic pressure:-

When two solution with different concentration of solute are separated by semi permeable membrane. There will occur a passage of water through the membrane in the direction of higher concentration.
That tend is equalising the concentration of solute on the both sides of the membrane the cell or exposed to the solution with higher solute concentration water will be drawn out of the cell. The process is called plasmolysis.
The reverse process that in the passage of water from a low solute concentration in to the cell is termed as plasmolysis.
The pressure built up within the cell as a result of this water intake is termed as osmotic pressure.


Energy transmitted through space in a variety of forms is generally called radiation.
Electromagnetic radiation has the dual properties of a continuous wave phenomenon and discontinuous practice phenomenon.
The particles of packet of quanta of energy sometimes called photons. The u.v portion of spectra include all radiations from 150-3900a0.
2650a0have a highest bacterial efficiency.
U.v light is observed by many cellular materials but most significant by the nuclear acids where it does the most damage.
One important alternation is the formation of a pyramid dimer in which two adjacent pyrimidines became bonded.
X -rays are lethal to microorganisms and higher form of life.
X -rays have been widely employees experimentally to produced microbial mutants.
 γ-radiation are high energy radiations emitted from certain radioactive isotopes such as 60 c0.
Γ-rays are similarly to x-rays but are of shorter wavelength and higher energy they are capable of great penetration into matter and they are lethal to all life including microorganisms.


Filters remove microorganisms from liquids of gases. These filters are made of different materials on asbestos pad in the sterilizer filter diatomaceous earth in the berkefeld filter, procelin in the chamber land and pasteur filter.
The mean pore diameter in the biological filter ranges from app. One to several micrometres.
New type of filter termed the membrane or molecular filter has been developed whose pores of a uniform and the specific predetermined size.
Membrane of molecular filters are composed of biological inert cellulose ester.
Membrane filters are used to sterilize fluids materials.
The development of high efficiency particular air {hepa} filters has been made it possible to deliver. Clean air it is in the system of laminar air flow.

Chemical control:-


Ethyl alcohol is concentration of 50% and 90% is effective against vegetative or non spore cells.
Generally 70% of alcohol is used in  lab.
Ethyl alcohol concentration of effective against vegetative cells and particularly inert against bacterial spores.
Methyl alcohol is less bacterial then ethyl alcohol and it is highly poison.
Fumes of methyl alcohol may produce permanent injury to the eyes.
Higher alcohols propyl, butyl amyl and other are more germicidal then ethyl alcohol.

Mode of action:-

Alcohol are protein denaturants and show antimicrobial activity.
Alcohols may damage the lipid complexes in cell membrane.
They are also dehydrated agents.
Cleansing ,detergent action. Removal of microorganisms.


Iodine is one of the oldest and most effective germicidal agents.
Iodine is slightly soluble in water but readily soluble in alcohol.
It is a germicidal agent in the form of referred to as tincture of iodine.
Iodine is also used in the form of substances known as iodophores.
One of the iodophores is polyvinyl pyrolidane {pvp} its show germicidal property and low limited properties.

Mode of action:-

Iodine is an oxidizing agent may account for its antimicrobiology action.
Oxidizing agent can irreversibely oxidize and thus inactive essential metabolic compounds such as proteins with sulphydrl groups.
It is involved in halogenation of tyrosine units of enzymes and other cellular proteins requiring tyrosine for activity.

Gaseous agents:-

Ethylene oxide:-

It is a simple organic compounds. It is a liquid at temperature below 10.80c above this temperature it is vapourises  rapidly.
It is highly flammable even in low concentration.
It is powerful sterilizing agent, used in hospitals industries and labs.

Mode of action:-

The mode of action of ethylene oxide is believed to be alkylation reaction with organic compounds such enzymes and other proteins.
It lacks the penetrating power but more active against microorganisms it is sporicidal, fungicides, virucidal.

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