Microbial Control Flashcards

Vocabulary practice flashcards covering terminology, key figures, physical methods, and chemical agents in microbial control based on the lecture material.

Girolamo Fracastoro

Proposed in 1546 that seed-like 'spores' cause disease and may be transferred between individuals via direct contact, contaminated clothing, or air.

Ignaz Semmelweis

Promoted handwashing before medical procedures, such as childbirth, to prevent puerperal fever in mothers.

John Snow

Conducted studies tracking the source of cholera outbreaks in London.

Louis Pasteur

Developed vaccines for fowl cholera, rabies, and anthrax.

Edward Jenner

First to commercialize a vaccine against smallpox using cowpox scabs.

Emil von Behring

Developed a diphtheria antitoxin to combat a major cause of childhood death.

Paul Ehrlich

Discovered salvarsan for the chemical treatment of syphilis.

Alexander Fleming

Discovered penicillin, the first widely used antibiotic.

Howard Florey and Ernst Boris Chain

Isolated penicillin for clinical use, sharing the Nobel Peace Prize with Alexander Fleming.

Gerhard Domagk

Discovered the antimicrobial properties of sulfanilamide (Prontosil®).

Selman Waksman

Discovered streptomycin, an antibiotic derived from soil organisms.

Sterilization

The removal or destruction of ALL living microorganisms from an object or surface.

Commercial Sterilization

Sufficient heat treatment to kill endospores of Clostridium botulinum in canned food.

Sanitization

Treatment intended to lower microbial counts on eating and drinking utensils to safe public health levels.

Antisepsis

The destruction or removal of vegetative pathogens on living tissue.

Disinfection

The destruction or removal of vegetative pathogens on inanimate objects.

-cide

A suffix meaning to kill, applied to treatments causing the death of microorganisms.

Biocide

A chemical agent or treatment that kills microorganisms in general; also known as a germicide.

Fungicide

A specific chemical agent or treatment that kills fungi.

-stat (-stasis)

A suffix meaning to stop or to steady, applied to treatments that inhibit microbial growth and multiplication.

Fungistatic

An agent or treatment that inhibits the growth and multiplication of mold/fungi without directly killing them.

Bacteriostat

An agent or treatment that inhibits the multiplication of bacteria without directly killing them.

Degerming

The mechanical removal of microbes from a limited area, such as the skin around an injection site.

Sepsis

A condition indicating bacterial contamination.

Asepsis

The absence of significant microbial contamination.

Microbial Death Rate

The constant rate at which bacterial populations die when exposed to heat or antimicrobial chemicals.

Factors Affecting Antimicrobial Effectiveness

Variables influencing microbial control, including microbial load, temperature, organic matter, suspending medium, exposure time, and microbial characteristics.

Alteration of Membrane Permeability

A mechanism of microbial control where agents damage the plasma membrane's lipid and protein components, leading to cellular leakage.

Damage to Proteins and Nucleic Acids

A mechanism of microbial control involving denaturation of proteins and interference with DNA, RNA, or protein synthesis.

Dry Heat Sterilization

A method requiring temperatures of $148{-}260^\bullet\text{C}$ for at least 45 minutes to kill spores and vegetative microorganisms through oxidation.

Hot-Air Sterilization

A dry heat method using an oven at $170^\circ\text{C}$ for about 2 hours, commonly used for empty glassware.

Direct Flaming

A dry heat sterilization technique that burns contaminants to ashes on inoculating loops using a burner or alcohol lamp.

Incineration

A dry heat method that burns contaminated items, such as dressings, animal carcasses, and paper, to ashes.

Moist Heat Sterilization

A microbial control method that kills organisms through the coagulation and denaturation of cellular proteins, generally more effective than dry heat.

Boiling

A moist heat method at $100^\circ\text{C}$ that kills vegetative bacterial and fungal pathogens and many viruses within 10 minutes, but fails against endospores and parvovirus.

Autoclave

A steam-under-pressure device operating at $121^\circ\text{C}$ and 15 psi, killing all vegetative cells and endospores in 15–30 minutes.

Pasteurization

A brief heat treatment ($72^\circ\text{C}$ for about 15 seconds) that eliminates pathogens and spoilage microbes in milk without altering flavor.

Tyndallization

A fractional moist heat sterilization method at $100^\circ\text{C}$ using free-flowing steam across 2 to 3 days with alternating incubation intervals.

Inspissation

A fractional sterilization method conducted at $60^\circ\text{C}$ in an oven over 2 to 3 days, alternated with room temperature or incubation intervals.

Filtration

The passage of a liquid or gas through a screenlike material with pores small enough to retain microorganisms.

HEPA Filter

High-Efficiency Particulate Air filter designed to remove airborne microorganisms and allergens from the air.

Membrane Filter

A liquid filter composed of nitrocellulose or cellulose acetate used to remove bacteria, viruses, and large proteins from heat-sensitive solutions.

Refrigeration

A low-temperature control method ($0{-}7^\circ\text{C}$) that exerts a bacteriostatic effect by decreasing chemical reaction rates.

High Pressure Processing (HPP)

A non-thermal food preservation method that alters the molecular structure of proteins and carbohydrates to kill microbes while preserving flavor and nutrients.

Desiccation

The removal of water from microorganisms, leading to disruption of metabolism and primarily causing a bacteriostatic state.

Osmotic Pressure

The application of high salt or sugar concentrations to induce plasmolysis and loss of water from microbial cells.

Non-Ionizing Radiation

Radiation, such as ultraviolet (UV) light, that damages DNA by forming pyrimidine dimers but possesses poor penetrating power.

Ionizing Radiation

High-energy radiation (gamma rays or beta electron beams) that destroys DNA by removing electrons from atoms and molecules.

Use-Dilution Test

The standard test specified by the AOAC to evaluate disinfectant efficacy against S. choleraesuis, S. aureus, and P. aeruginosa.

Filter Paper Method

A disk-diffusion technique where chemical-soaked paper disks are placed on inoculated agar to measure zones of inhibition.

Phenol

A chemical disinfectant that disrupts plasma membranes and denatures enzymes; historically used as a standard of comparison.

Phenolics

Chemical derivatives of phenol, such as cresols and hexachlorophene, used on environmental surfaces, instruments, and skin.

Bisphenols

Phenol derivatives commonly incorporated into disinfectant hand soaps and skin lotions.

Chlorhexidine

A biguanide agent that damages plasma membranes of vegetative cells; widely used for surgical hand scrubbing.

Terpenes

Essential oils derived from plants used for food preservation and disinfecting hard surfaces.

Iodophor

A combination of iodine and an organic molecule that slowly releases iodine for effective skin antisepsis.

Hypochlorous Acid

A strong oxidizing agent formed when chlorine gas or chlorine compounds are added to water.

Alcohols

Chemical agents (e.g., aqueous ethanol 60%–90% or isopropanol) that denature proteins and dissolve lipids; ineffective against endospores or nonenveloped viruses.

Oligodynamic Action

The ability of tiny amounts of heavy metals (like silver, mercury, copper, and zinc) to exert antimicrobial activity by denaturing proteins.

Soaps and Detergents

Surface-active agents that mechanically remove microbes and debris through scrubbing and degerming.

Acid-Anionic Sanitizers

Sanitizers used in dairy and food-processing industries that function through enzyme inactivation or disruption.

Quaternary Ammonium Compounds (Quats)

Cationic detergents attached to $NH_4^+$ that disrupt plasma membranes; highly effective against gram-positive bacteria.

Organic Acids

Preservatives like sorbic acid, benzoic acid, and propionic acid that inhibit fungal metabolism in foods and cosmetics at low pH.

Nitrites

Active antimicrobial agents in meat products produced from nitrate that inhibit iron-containing enzymes of anaerobic bacteria like Clostridium botulinum.

Aldehydes

Disinfectants such as formaldehyde and glutaraldehyde (Cidex®) that inactivate proteins and achieve high-level disinfection.

Ethylene Oxide

A gaseous chemosterilant that penetrates materials and kills all microorganisms by protein denaturation, ideal for heat-sensitive items.

Peroxygens

Powerful oxidizing agents, such as hydrogen peroxide and ozone, used on contaminated surfaces and deep wounds to target anaerobes.