Control of Microbial Growth

A collection of vocabulary flashcards based on the lecture notes on microbial growth control, featuring key terms and definitions.

Microbial Colony-Forming Units (CFUs)

A measure of viable microorganisms present in a sample, indicating the level of microbial contamination.

Antisepsis

Reduction in the number of microorganisms on living tissue, typically achieved using substances like iodine or alcohol.

Aseptic Technique

Procedures designed to prevent contamination by pathogens during medical and laboratory procedures.

Degerming

The mechanical removal of microbes from a surface, often involving handwashing or alcohol swabbing.

Disinfection

Destruction of most microorganisms on nonliving tissue, using agents like phenolics or alcohols.

Sterilization

Complete destruction of all microorganisms and viruses in or on an object, often through extreme heat or chemicals.

Sanitization

Reduction of pathogenic microorganisms to levels deemed safe based on public health standards.

-cide / -cidal

Suffixes indicating the killing of a specific type of microbe, such as bactericide or fungicide.

Thermal Death Point

The lowest temperature that kills all cells in a broth in 10 minutes.

Thermal Death Time

The time required to sterilize a given volume of liquid at a set temperature.

Moist Heat Sterilization

A method that uses steam or boiling water to kill microorganisms and is more effective than dry heat.

Autoclaving

A method of sterilization using steam under pressure, often set at 121°C for 15 minutes.

Pasteurization

The application of high heat for a short time to kill pathogenic microorganisms in food and beverages.

Filtration

A method used to remove microorganisms from liquids or air by passage through a filter.

Ionizing Radiation

High-energy radiation that ejects electrons from atoms, potentially damaging DNA of microorganisms.

Nonionizing Radiation

Lower-energy radiation that can cause abnormal bonds in DNA, used for disinfection.

Biosafety Levels (BSL)

Categories that define the level of safety precautions required when working with pathogens in laboratory settings.

Osmotic Pressure

The use of high concentrations of salt or sugar to inhibit microbial growth by drawing water out of cells.

Desiccation

The process of drying, which inhibits microbial growth by removing water.

Lyophilization

A preservation method that involves freeze-drying to prolong the shelf life of microbial cultures.

Surfactants

Chemicals that lower the surface tension of liquids, often used in soaps and detergents for cleaning.

Halogens

Chemical agents such as iodine and chlorine that are widely used as disinfectants.

Oxidizing Agents

Chemicals like hydrogen peroxide that kill microorganisms by oxidizing their enzymes.

Heavy Metals

Metals, such as mercury and silver, that can denature proteins and act as antimicrobial agents.

Aldehydes

Compounds that disrupt protein structure and nucleic acid function, used in disinfection and sterilization.

Gaseous Agents

Chemicals that are effective at sterilizing equipment but can be hazardous due to their toxicity.

Enzymes

Proteins that can selectively target and destroy microorganisms, such as lysozyme found in human tears.

Antimicrobial Drugs

Chemical agents, including antibiotics, that are used for treating infections and controlling microbial growth.

Use-Dilution Test

A standard method for evaluating disinfectant efficacy by testing the growth of organisms on metal cylinders.

In-Use Test

A method that involves monitoring swabs taken from surfaces before and after the use of disinfectants.

Relative Susceptibilities of Microbes

Classification of microbes based on their resistance to antimicrobial agents: high, intermediate, low.

Chemical Methods of Microbial Control

Techniques that alter cell walls, membranes, proteins or nucleic acids to control microbial growth.

Antimicrobial Resistance

The ability of microbes to withstand the effects of medications that once killed them or inhibited their growth.

Decimal Reduction Time (D-value)

The time required to kill 90% of a specific microorganism at a given temperature.

Phenol Coefficient

A measure of the effectiveness of disinfectants compared to phenol.

Quaternary Ammonium Compounds (Quats)

Cationic detergents that disrupt cellular membranes and are used in disinfectants.

Bacteroides

A genus of bacteria that can be resistant to many types of antimicrobial agents.

Campylobacter jejuni

A bacterium commonly associated with foodborne illness, often found in unpasteurized dairy.

Antiseptic vs. Disinfectant

Antiseptics are used on living tissue, while disinfectants are used on inanimate objects.

Food Poisoning

Illness caused by consumption of contaminated food or beverages, often leading to gastrointestinal symptoms.

Microbial Growth Control Methods

Strategies employed to reduce or eliminate microbial populations in various environments.

Cytoplasmic Membrane Damage

Disruption of the cell membrane integrity, leading to loss of essential cellular materials.

Cell Wall Integrity

The structural support of a cell that prevents it from bursting during osmotic pressure changes.

Antimicrobial Efficacy Factors

Conditions such as temperature, pH, and concentration of microbes that affect the success of antimicrobial agents.

Incineration

A sterilization method that destroys all microorganisms through extreme heat.

Surgical Asepsis

A technique that ensures any medical procedure is completely free from all microorganisms.