At what time was pasteurization of dairy products widely used?
1895
Which of the following disease outbreaks can be controlled by making sure there is clean water and food?
cholera
The time necessary to kill a population of microbes at a given temperature is called the
thermal death time.
A fluid that has been sterilized may still contain
bacterial toxins.
Which one of the following is the most rapid method for achieving sterilization?
Direct flame method
Of the following, the most efficient method for sterilization of a bacteriological transfer loop is
the direct flame.
The minimal temperature at which a microbial species dies in a given time is called the
thermal death point
A period of two hours at 160° C is required for the destruction of endospores
in the hot air oven.
The hot air method of sterilization is useful for those items that
are dry or do not mix with water.
Bacterial endospores must be exposed for a period of over 2 hours for destruction with
the hot air oven.
Moist heat kills microorganisms by
denaturation.
If boiling water is used to destroy microorganisms, it is imperative that
traces of organic matter be removed.
In an autoclave under 15 lb/in2 steam pressure, the approximate temperature will be _______.
121.5° C
One of the limitations of the autoclave is that
some plasticware melts in the high heat.
Which one of the following could not be sterilized by the autoclave?
A laboratory table
Using a prevacuum stage in the autoclaving process can effectively
reduce the time to achieve sterilization.
Sterilization by fractional sterilization requires
a period of three days.
A substance that has been pasteurized
is not considered sterile.
The conditions necessary to kill Mycobacterium tuberculosis by pasteurization are
30 min at 62.9° C.
When applied to wounded tissue, hydrogen peroxide
releases oxygen gas.
Formalin may be used for all the following purposes except
purifying of drinking water.
The chemical counterpart of the autoclave uses
ethylene oxide with an inert gas.
Detergents display their antimicrobial ability by
inducing leakage through the cell membrane.
An advantage of the membrane filter is that
bacteria multiply and form colonies on its surface.
HEPA filters are used to filter which one of the following?
Air
The principle effect of ultraviolet light on bacterial cells takes place
in the DNA of the cell.
One drawback to the use of ultraviolet light as a sterilizing agent is its failure to
penetrate liquids or solids.
Ultraviolet light is valuable for reducing the microbial population in
the air of a hospital room.
For UV light to kill microorganisms
direct exposure must take place.
Energy wavelengths near 265 nm are most destructive when one is using
ultraviolet light.
Radiations with wavelengths between 400 nm and 800 nm are considered
visible light.
In the microwave oven, the energy of microwaves is converted to
the heat of friction.
When food has been salted
water diffuses out of microorganisms causing them to shrivel.
Low temperature is
bacteriostatic.
A method of preserving food that depends upon osmosis is
treating the food with high concentrations of sugar.
The halogen common to Wescodyne®, Betadine®, and Ioprep®
iodine in a form known as iodophor.
Which one of the following elements would be classified as a halogen?
Chlorine
Iodophors are
complexes of iodine and detergents that release iodine over long periods of time.
Which one of the following statements does not apply to phenol?
It has a low cost, a sweet odor, and no effects on the skin.
Chlorhexidine is a phenol derivative used to
wash hands and clean wounds superficially.
Triclosan destroys bacteria by
disrupting cell membranes.
Copper has its principle activity against
organisms that contain chlorophyll.
Silver nitrate may be used to
prevent gonorrhea in the eyes of newborns.
Mercury is rarely used in antiseptics in the modern era because
mercury is very toxic to body tissues.
Heavy metals generally kill microorganisms by
reacting with proteins and binding them together.
At a concentration of 70 percent, ethyl alcohol has virtually no effect on
bacterial spores.
Before alcohol is used for disinfection purposes
the object to be treated must be carefully cleaned.
destroys bacterial endospores with heat in about 15 minutes.
The autoclave
also is known as tyndallization.
Fractional sterilization
oxidizes proteins and creates an arid environment.
The hot air oven
is electromagnetic energy with a wavelength between 100 and 400 nm.
Ultraviolet (UV) light
uses pressurized steam at 121°C.
The autoclave
causes linkage of adjacent thymine molecules on DNA.
Ultraviolet (UV) light
employs 30 minutes of steam on three successive days.
Fractional sterilization
requires a two-hour exposure for the destruction of bacterial endospores.
The hot air oven
uses free-flowing steam at 100°C.
Fractional sterilization
interferes with replication of the bacterial chromosomes.
Ultraviolet (UV) light
can be used to sterilize an environmental surface.
Ultraviolet (UV) light
is the most dependable method for the destruction of endospores.
The autoclave
uses dry heat used for sterilization.
The hot air oven
will melt plasticware in the pressurized steam.
The autoclave
is a heat-free method of sterilization.
Ultraviolet (UV) light
sharp instruments often become dull during this procedure.
The autoclave
is useful for water-free oily substances and dry powders.
The hot air oven
can have a prevacuum stage to increase the efficiency of sterilization.
The autoclave
can reduce airborne contamination effectively.
Ultraviolet (UV) light
has effects on microorganisms equivalent to that of baking
The hot air oven
Ultraviolet light
Radiation at 265 nm that is absorbed by DNA
Pasteurization
Heating liquids to 62.9°C for 30 minutes
Osmosis
Water movement across a membrane toward the area where water concentration is lower
Thermal death time
Time required to kill an organism at a specific temperature
Autoclave
Chamber for steam sterilizing at 121°C
Membrane filter
Cellulose acetate pad through which fluids, but not cells, pass
Sterilization
Process that kills all living organisms and spores
Thermal death point
Minimal temperature at which an organism dies in a given time period
Sanitization
Microbiostatic
and
microbial populations have been reduced or where their growth has been inhibited
denaturation
change in the chemical or physical property of a protein.
Incineration
using a direct flame can kill microbes very rapidly
<p>Thermal death time</p> <br>
the time necessary for killing the population at a given temperature
Thermal death point
minimal temperature at which it dies in a given time
Filtration
mechanical method used to remove microorganisms from a solution, organisms are trapped in the pores of the filter
Sterilization
microbicidal
and
the destruction of all living microbes, including spores and viruses, on an object or in an area
Pasteurization
reduces the bacterial population of a liquid such as milk and destroys organisms that may cause spoilage and human disease
autoclave
Moist heat in the form of pressurized steam is regarded as the most dependable method for sterilization
prevacuum autoclave
draws air out of the sterilizing chamber at the beginning of the cycle.