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.