Control of micro organisms by radiation and how radiations are lethal to microbes. Types of radiation that are affective against microbes.

1. Presentation of
microbiology
Name:Ayesha tahir
Roll No.871
Uni roll no:023822
Presented to:sir fazal elahi

2. Control of micro
organisms by radition

3. Control of micro organisms
Control of microbial growth means to inhibit or
prevent growth of microorganisms.
OR
The term control refers to the reduction in number
or activity of total microbial flora

4. Importance of micro-organisms
Microbes are important.
• Play key role in nutrition cyle
• Biodegradion
• Climate change
• Control the diseases

5. Reasons for controlling micro
organisms
• Control of microorganisms is essential in order to
prevent the transmission of diseases and infection
• stop decomposition and spoilage
• prevent unwanted microbial contamination.

6. Radiation
Radiation is energy that comes from a source and
travels through space at the speed of light. This
energy has an electric field and a magnetic field
associated with it, and has wave-like properties. You
could also call radiation “electromagnetic waves”.

10. Gamma rays
• High energy Radiation
• Emit from certain radio isotopes such as Co.
• The are capable of great penetration into matter.
• The are lethal to all life including micro organisms

11. Physical STERLiZSTION/Radition
STERLiZSTION
STERLiZSTION by radition is known as cold
STERLiZSTION.
Beacuse no heat is use in this method .
Radition STERLiZSTION relies on ionizing
radition.Gamma rays play important role in cold
STERLiZSTION.

12. X Rays
• Lethal to micro organisms
• Unlike ultra violet radition they have
considerable energy and penetration ability.
• They are impractical for purpose of
controlling microbial population bcz they are
expensive.

13. How ionizing radiation control the
growth of microbes
radiation causes damage to the genetic material - the
DNA or the RNA - of the organism's cell.
If the DNA or RNA of a microorganism is damaged,
the cell will die.

15. Non-ionizing radiation
Non-ionizing radiation is any kind of radiation in
the electromagnetic spectrum that does not have
enough energy to remove an electron from an
atom and turn it into an ion.
Non-ionizing radiation includes the spectrum of
ultraviolet (UV), visible light, infrared (IR),
microwave (MW).

16. Ultra violet radiation
• The ultra violet portion of spectrum include all
radiation from 150-3900 Å.
Lamps
• All availablewhich emit high concentration of UV light
in the most effective region, 2600-2700Å.
Example
• Germicidal lamps which emit UV radiation are widely
used to reduce microbial population. e.g. Hospital
operating rooms, pharmaceutical industries, food and
dairy industriesfor treatmentof contaminating surfaces.

17. Mode of action
Ultraviolet light is absorbed by many cellular
material but most significantly by nucleic acid
where it does the most demage.
Demage DNA by producing thyamine dimers which
cause mutation.