CHAPTER 9 Flashcards
the eradication of microorganisms and viruses; the term is not usually applied to the destruction of prions.
sterilization
environment or procedure is free of contamination by pathogens
aseptic
the inhibition/killing of microorganisms (particularly pathogens) on skin or tissue by the use of a chemical antiseptic
Antisepsis
refers to the use of agents (called disinfectants) to inhibit microbes on inanimate objects.
Disinfection
refers to the removal of microbes from a surface by scrubbing.
degerming
the reduction of a prescribed number of pathogens from surfaces and utensils in public settings.
Sanitization
process using heat to kill pathogens and con- trol microbes that cause spoilage of food and beverages.
Pasteurization
This suffix indicates that an antimicrobial agent inhibits microbes
Stasis and static
This suffix indicates that the agent kills or permanently inactivates a particular type of microbe.
Cide and tidal
permanent loss of reproductive capacity.
Microbial death
measures the efficacy of an antimicrobial agent.
Microbial death rate
Antimicrobial agents destroy microbes either by
Altering their cell walls and membranes or by interrupting their metabolism and reproduction
Factors affecting the efficacy of antimicrobial methods include
site to be treated, the relative susceptibility of microorganisms, and environmental conditions.
lowest temperature that kills all cells in a broth in 10 minutes
Thermal death point
the time it takes to completely sterilize a particular volume of liquid at a set temperature
Thermal death time
the time required to destroy 90% of the microbes in a sample.
Decimal reduction time
uses steam heat under pressure to sterilize chemicals and objects that can tolerate moist heat.
Autoclave
Methods of pasteurization
the historical (batch) method, flash pasteurization, and
ultra-high-temperature pasteurization.
Under certain circumstances, microbes can be controlled using
ultra-high-temperature sterilization, dry-heat sterilization, incin- eration, refrigeration, or freezing.
Antimicrobial methods involving drying are _, used to preserve food
Desiccation
used for the long-term preservation of cells or microbes.
Lyophilization( freeze- drying)
the passage of air or a liquid through a material that traps and removes microbes.
Filtration
have pores small enough to trap the smallest viruses.
Membrane filters
What is the meaning of HEPA
High-efficiency particulate air
exerted by hypertonic solutions of salt or sugar can preserve foods such as jerky and jams by removing from microbes the water that they need to carry out their meta- bolic functions.
High osmotic pressure
includes high-speed subatomic particles and
even more energetic electromagnetic waves released from atoms.
Radiation
(wavelengths shorter than 1 nm) produces ions that denature important molecules and kill cells.
Ionizing radiation
(wavelengths longer than 1 nm) is less effective in microbial control, although UV light causes pyrimidine dimers, which can kill affected cells.
Nonionining radiation
are chemically modified phenol molecules, are intermediate- to low-level disinfectants that denature proteins and disrupt cell membranes in a wide variety of pathogens.
Phenolics
intermediate-level disinfectants that denature pro- teins and disrupt cell membranes; they are used either as 70% to 90% aqueous solutions or in a tincture, which is a combination of an alcohol and another antimicrobial chemical.
Alcohols
(iodine, chlorine, bromine, and fluorine) are used as intermediate-level disinfectants and antiseptics to kill microbes by protein denaturation in water or on medical instruments or skin.
Halogens
such as hydrogen peroxide, ozone, and per- acetic acid are high-level disinfectants and antiseptics that release oxygen radicals, which are toxic to many microbes, especially anaerobes.
Oxidizing agents
include soaps, which act primarily to break up oils during degerming
Surfactants
such as quaternary ammo- nium compounds (quats), which are low-level disinfectants.
Detergents
such as ions of arsenic, silver, mercury, copper, and zinc, are low-level disinfectants that denature proteins.
For most applications they have been superseded by less toxic alternatives.
Heavy metal ions
are high-level disinfectants that cross-link organic functional groups in proteins and nucleic acids. A 2% solution
of glutaraldehyde or a 37% aqueous solution of formaldehyde (called formalin) is used to disinfect or sterilize medical or dental equipment and in embalming fluid.
Aldehydes
Many organisms use __ to combat microbes. Humans use them commercially in food preservation and as a
Antimicrobial enzymes
include antibiotics, semisynthet- ics, and synthetics, are compounds that are typically used
to treat diseases but can also function as intermediate-level disinfectants.
Anti microbial drugs
Four methods for evaluating the effectiveness of a disinfectant or antiseptic are the
phenol coefficient, the use-dilution test, the Kelsey-Sykes capacity test, and the in-use test.
