Microbial Growth and Control

A comprehensive set of flashcards covering the vocabulary and key concepts related to microbial growth and control as presented in the lecture notes.

Microbial Classification

Classifying microbes based on their preferred temperature range.

pH Control

Managing the pH of culture media to optimize microbial growth.

Osmotic Pressure

The pressure required to prevent the flow of water across a semipermeable membrane, influencing microbial growth.

Carbon, Nitrogen, Sulfur, Phosphorus

Elements needed in large amounts for microbial growth; each has specific uses.

Aerobes

Microbes that require oxygen to grow and have mechanisms to avoid damage from toxic forms of oxygen.

Biofilms

Aggregates of microorganisms that form a protective layer, increasing infection risk.

Chemically Defined Media

Culture media with precisely known chemical composition.

Complex Media

Culture media composed of extracts from plants or animals, with unknown composition.

Biosafety Levels

Levels 1-4 that classify laboratory practices and containment measures based on risk.

Colony

A visible mass of microorganisms derived from a single mother cell.

Streak Plate Method

A technique to isolate pure cultures by spreading a diluted microbial sample across an agar plate.

Bacterial Growth

Increase in bacterial cells; typically occurs through binary fission.

Microbial Growth Phases

Different stages of growth including lag, log, stationary, and death phase, each correlating to generation time.

Direct Methods of Measuring Growth

Techniques such as viable cell counts, total cell counts, dry weight, and metabolic activity to quantify microbial growth.

Indirect Methods of Measuring Growth

Methods such as turbidity measurement, metabolic activity, or dry weight that estimate cell numbers without direct counting.

Sterilization

The process of killing or removing all forms of microbial life.

Disinfection

Destruction of harmful microorganisms on non-living surfaces.

Asepsis

Absence of significant contamination, critical in surgical environments.

Antisepsis

Destruction of harmful organisms on living tissues.

Degerming

Mechanical removal of microbes from a limited area.

Biocide (Germicide)

Treatments that kill microorganisms.

Bacteriostasis

Inhibition of bacterial growth without killing them.

Thermal Death Point (TDP)

The lowest temperature at which all organisms in a liquid culture are killed in 10 minutes.

Decimal Reduction Time (DRT)

Time it takes to kill 90% of a specific bacterial population at a given temperature.

Heat Sterilization

Using heat to denature proteins and kill microorganisms.

Pasteurization

A heat treatment that reduces spoilage organisms and pathogens.

Cold Temperature Effects

Low temperatures that inhibit microbial metabolism.

Filtration

A method to remove microbes from liquids using a barrier.

Ionizing Radiation

High-energy radiation that destroys microbes by damaging their DNA.

Nonionizing Radiation

Ultraviolet light that damages DNA and affects microbial growth.

Use-Dilution Tests

A method to determine the efficacy of disinfectants against microorganisms.

Disk Diffusion Method

A technique to evaluate the efficacy of chemical agents by measuring zones of inhibition.

Halogens

Elements such as iodine and chlorine used in disinfection and antisepsis.

Phenolic Compounds

Chemical agents that disrupt plasma membranes and have antimicrobial properties.

Alcohols

Chemical agents that denature proteins and dissolve lipids but are ineffective against non-enveloped viruses.

Heavy Metals

Elements that exert antimicrobial effects in minimal amounts by denaturing proteins.

Surface-Active Agents (Surfactants)

Chemicals that reduce surface tension, enhancing the efficacy of cleaning agents.

Chemical Food Preservatives

Substances added to food to prevent spoilage and microbial growth.

Aldehydes

Chemical agents used for preserving specimens by cross-linking proteins.

Antibiotics

Substances produced by microorganisms that inhibit other microbes.

Chemical Sterilization

Using gaseous agents to alkylate chemical groups, leading to microbial death.

Peroxygens

Oxidizing agents that are effective in disinfecting surfaces.