Physical Methods of microbial control

Decontamination

Destruction, removal, or reduction in the number of undesirable microbes.

Sterilization

The removal or destruction of all viable microbes.

Disinfection

Destruction of vegetative pathogens on inanimate objects.

Sepsis

The growth of microorganisms in the tissues.

Asepsis

Techniques that prevent the entry of microorganism into stereo tissues.

Antiseptics

Chemicals used on body surfaces.

Sanitization

Cleansing technique that removes microorganisms and debris from inanimate surfaces.

Degermation

Cleansing technique that removes microorganisms and debris from living tissue.

Physical agents used to kill microbes:

Heat and radiation

Dry heat

incineration results in sterilization.

Moist heat

steam under pressure results and sterilization. (auto clave)

boiling water results in disinfection

pasteurization results in disinfection

Radiation

• Ionizing

• Non-ionizing

Gamma Radiation

• One type of ionizing radiation

• Collides with molecules in the cell

• Creates free radicals

• Resulting in DNA breakages

Ultraviolet radiation

• One type of nonionizing radiation

• Kills by damaging DNA

• Triggers Mutations in DNA (thymine dimers)

• Causes direction protein damage

Limitations of ultraviolet radiation

• Cannot go through plastic or glass

• Mainly used for killing microbes on surfaces, air, water

• Damages retina of eye

• Must be used when people are not present.