Ch. 11 Physical And Chemical Agents For Microbial Control

Front 1

highest resistance

Back 1

prions, bacterial endospores

Front 2

least resistance

Back 2

most bacterial vegetative cells, fungal spores and hyphae, enveloped viruses, yeasts, protozoan trophozoites

Front 3

sterilization

Back 3

process that destroys or removes all viable microbes

Front 4

sterile

Back 4

any material that has been subjected to sterilization

Front 5

bactericide

Back 5

chemical that destroys bacteria except for those in the endospore stage

Front 6

fungicide

Back 6

chemical that can kill fungal spores, hyphae, and yeasts

Front 7

virucide

Back 7

chemical known to inactivate viruses, especially on living tissue

Front 8

sporicidal

Back 8

agent that can destroy bacterial endospores

Front 9

bacteriostatic agent

Back 9

prevents the growth of bacteria on tissues or on objects

Front 10

fungistatic agent

Back 10

inhibit fungal growth

Front 11

germicide

Back 11

any chemical agent that kills pathogenic microbes

Front 12

disinfection

Back 12

the use of a physical process or a chemical agent (a disinfectant) to destroy vegetative pathogens, but not bacterial endospores

Front 13

sepsis

Back 13

growth of microbes in the blood and other tissues

Front 14

asepsis

Back 14

any practice that prevents the entry of infectious agents into sterile tissues and thus prevents infection

Front 15

antisepsis

Back 15

use of chemical agents (antiseptics) on exposed body surfaces to destroy or inhibit vegetative pathogens

Front 16

sanitization

Back 16

any cleansing technique that removes debris, microbes, and toxins, and in this way reduces the potential for infection and spoilage

Front 17

degermation

Back 17

reduction in microbial load through mechanical means

Front 18

microbial definition of death

Back 18

the permanent loss of reproductive capability, even under optimum growth conditions

Front 19

factors that influence the action of antimicrobials

Back 19

1. # of microbes

2. nature of the microbes in the population

3. temperature & pH

4. agent concentration

5. mode of action of the agent

6. presence of solvents, interfering organic matter, and inhibitors

Front 20

surfactants

Back 20

chemicals that lower the surface tension of cell membranes

Front 21

denaturation

Back 21

when the bonds that maintain the secondary and tertiary structure of the protein are broken, disrupting the structure and function of the protein

Front 22

moist heat

Back 22

in the form of hot water, boiling water, or steam

temp from 60-135C

Front 23

dry heat

Back 23

air with low moisture content that has been heated by a flame or electric heating coil

temp from 160-several thousandC

Front 24

thermal death time (TDT)

Back 24

shortest length of time required to kill all test microbes at a specified temp

Front 25

thermal death point (TDP)

Back 25

lowest temp required to kill all microbes in a sample in 10 minutes

Front 26

autoclave

Back 26

device that can subject pure steam to pressures greater than 1 atm; sterilization is achieved when the steam condenses against the objects in the chamber and gradually raises their temp

Front 27

tyndallization

Back 27

for substances that cannot withstand the high temp of an autoclave (is nonpressurized)

Front 28

pasteurization

Back 28

technique in which heat is applied to liquids to kill potential agents of infection and spoilage, while at the same time retaining the liquid's flavor and food value

Front 29

flash method

Back 29

pasteurization technique that exposes the liquid to heat exchanges

Front 30

incineration

Back 30

most rigorous treatment in a flame or electric heating coil; ignites and reduces microbes to ashes and gas

Front 31

desiccated

Back 31

to dry at normal environmental temps

Front 32

lyophilization

Back 32

common method of preserving microbes in a viable state that includes a combo of freezing and drying

Front 33

radiation

Back 33

energy emitted from atomic activities and dispersed at high velocity through matter and space

Front 34

ionizing radiation

Back 34

when the radiation ejects orbital electrons from an atom, it causes ions to form

Front 35

nonionizing radiation

Back 35

excites atoms by raising them to a higher energy state, but it does not ionize them

Front 36

cold sterilization

Back 36

sterilization in the absence of heat

ex: irradiation

Front 37

ultraviolet (UV) radiation

Back 37

ranges in wavelength from approximately 100 nm to 400 nm. it is most lethal from 240 nm to 280 nm

Front 38

pyrimidine dimers

Back 38

abnormal linkages with pyrimidine bases (thymine and cytosine) formed by molecular damages

Front 39

categories of chemical agents

Back 39

halogens

phenols

chlorhexidine

alcohols

hydrogen peroxide

aldehyde sterilants & disinfectants

gaseous sterilants & disinfectants (ethylene oxide)

detergents & soaps (quats)

heavy metals

dyes

acids & alkalis

Front 40

halogens

Back 40

chlorine & iodine

they break disulfide bridges on cysteines on enzymes to denature the enzyme

Front 41

phenols

Back 41

high conc: disrupt cell wall & membrane & protein

low conc: inactivate enzyme systems

Front 42

chlorhexidine

Back 42

lowers surface tension of cell membranes and denatures protein structure

Front 43

alcohols

Back 43

dissolve membrane lipids, disrupt cell surface tension, compromise membrane integrity

Front 44

hydrogen peroxide

Back 44

forms free radicals that are highly toxic to cells

Front 45

aldehydes

Back 45

(glutaraldehyde & formaldehyde)

disrupts protein cross-linking and enzyme activity

Front 46

gaseous sterilants and disinfectants

Back 46

ethylene oxide

blocks DNA replication and enzymatic action by reacting with functional groups of DNA and proteins

Front 47

detergents and soaps

Back 47

detergents act as surfactants and disrupt cell membranes

quats (quaternary ammonium compounds)

Front 48

heavy metals

Back 48

use mercury and silver

bind functional groups of proteins and inactivate them to stop metabolism

Front 49

dyes

Back 49

have a narrow spectrum of activity

Front 50

acids & alkalis

Back 50

pH destroys or inhibits cells