The Control of Microbial Growth Flashcards

Vocabulary flashcards covering microbial control terminology, physical and chemical sterilization techniques, and microbial resistance.

Sepsis

Microbial contamination.

Asepsis

The absence of significant microbial contamination.

Aseptic Surgery Techniques

Techniques designed to prevent microbial contamination of wounds during surgical procedures.

Sterilization

The destruction or removal of all microbial life.

Commercial Sterilization

Heat treatment designed to kill Clostridium botulinum endospores in canned foods.

Disinfection

The process of removing pathogens from non-living surfaces.

Antisepsis

The removal of pathogens from living tissue.

Sanitization

Lowering microbial counts on eating utensils to safe public health levels.

Biocide (Germicide)

A chemical or physical agent that kills microorganisms.

Bacteriostasis

A treatment method that inhibits the growth and multiplication of microbes without killing them.

Thermal Death Point (TDP)

The lowest temperature at which all microorganisms in a liquid suspension will be killed in $10$ ext{ minutes}.

Thermal Death Time (TDT)

The minimal length of time required to kill all bacteria in a liquid culture at a specified temperature.

Autoclave

A equipment that uses steam under pressure ($121^\text{o}\text{C}$ at $15$ ext{ psi} for $15$ ext{ minutes}) to achieve complete sterilization, including the destruction of endospores.

Pasteurization

Mild heating process that reduces spoilage organisms and eliminates pathogens in food and liquids without damaging the product.

Thermoduric Organisms

Heat-resistant bacteria that survive standard pasteurization processes.

Hot-Air Sterilization

A dry heat sterilization method requiring exposure to $170^\text{o}\text{C}$ for $2$ ext{ hours} to kill organisms by oxidation.

Membrane Filtration

Passage of liquid or gas through a screenlike material with microscopic pores to filter out microbes ($0.45$ ext{ }\null ext{ μm}$removes bacteria,$0.22$\text{ }$ ull$\text{ μm}$ is sterilizing grade, and $0.1$ ext{ }\null ext{ μm}$$ removes viruses).

Desiccation

The removal of water/drying out that prevents microbial growth and metabolic activity.

Osmotic Pressure (Microbial Control)

The creation of a hypertonic environment using high concentrations of salts and sugars to cause plasmolysis in bacterial cells.

Ionizing Radiation

High-energy radiation (X-rays, gamma rays, electron beams) with short wavelengths that directly damages DNA and ionizes water to produce reactive hydroxyl radicals.

Non-Ionizing Radiation

Radiation such as UV light (peak efficacy at $260$ ext{ nm}) that inhibits microbes by causing thymine dimers to form in DNA.

Thymine Dimer

A specific DNA lesion caused by UV light where adjacent thymine bases bond together, interfering with proper DNA replication.

Disk Diffusion Test

An assay used to evaluate the efficacy of a chemical agent by measuring the clear zone of inhibition produced around a treated filter paper disk placed on inoculated agar.

Residual Activity

The property of an antiseptic (such as Chlorhexidine) to remain active on the skin and inhibit microbial growth for several hours after application.

Oligodynamic Action

The ability of extremely small amounts of heavy metals (such as silver, copper, and zinc) to exert antimicrobial activity by denaturing proteins and damaging cell membranes.

Quaternary Ammonium Compounds (Quats)

Cationic detergent surface-active agents that denature proteins, disrupt plasma membranes, and act as bactericidal agents.

Microbial Resilience Hierarchy

The relative resistance of microorganisms to chemical and physical control methods, ranging from most resistant (prions, endospores) to least resistant (viruses with lipid envelopes).