Microbial Control Methods and Concepts

Comprehensive vocabulary flashcards covering the definitions, principles, and agents of physical and chemical microbial control.

Sanitization

A cleansing technique that mechanically removes microorganisms and other debris to reduce contamination to safe levels.

Antisepsis

The application of chemical agents directly to exposed body surfaces and living tissue to destroy or inhibit vegetative pathogens (e.g., an alcohol wipe or Betadine swab prior to a puncture).

Disinfection

A physical or chemical process used to destroy or remove vegetative microbial life forms from inanimate objects, such as countertops.

Sterilization

A process that completely destroys or removes all microorganisms and microbial forms, including bacterial endospores, from inanimate objects.

Microbial death

The permanent loss of reproductive capability in a microbial cell under optimal growth conditions.

Thermal death time (TDT)

The shortest length of time required to kill all test microbes in a sample at a specified temperature.

Thermal death point (TDP)

The lowest temperature required to kill all microbes in a sample within $10\,\text{minutes}$.

Incineration

A method of dry-heat sterilization utilized in the laboratory to sterilize inoculating loops before and after inoculating cultures.

Desiccation

The removal of moisture from microbial cells by dehydration, functioning as a bacteriostatic rather than bactericidal method.

Lyophilization

A freeze-drying process that preserves vials of microorganisms in a viable state for years.

Filtration

A microbial control method that mechanically removes microorganisms from liquids or air rather than inhibiting or killing them.

Bacterial endospores

Microbial survival structures that demonstrate the highest resistance to both physical and chemical control methods.

Enveloped viruses

Microbial entities that are the least resistant to chemical and physical control measures.

Chlorine

A halogen used in gaseous and liquid forms for large-scale disinfection of municipal drinking water and sewage.

Ethylene oxide

A gaseous chemical control agent that is sporicidal and capable of achieving sterility.

Ultraviolet (UV) radiation

A form of non-ionizing radiation that damages microbial DNA by inducing the formation of pyrimidine dimers.

Hydrogen peroxide

A chemical agent that exerts antimicrobial action by generating highly toxic and reactive free radicals.

Chlorhexidine

An antimicrobial agent that targets microbial cell membranes, cell walls, and denatures proteins to kill microbes.

Heavy metals

Chemical antimicrobial agents that control microbial growth primarily by inactivating proteins.

Pasteurization

A heat treatment process that reduces the number of vegetative pathogens in liquids rather than destroying all microbial forms.

Osmotic pressure

A method of microbial control that inhibits microbial growth through hypertonic solute environments, such as salting meat.

Denaturation

The breakdown of native protein structures caused by disrupting chemical bonds that maintain the functional shape of microbial proteins.

Rate of microbial death

The characteristic pattern observed in microbial populations where cells in a culture die at a constant rate.

Relative radiation penetration

The hierarchy of radiation forms ranked from most penetrating to least penetrating: Gamma rays, X rays, cathode rays.