Controlling in-vitro Growth

Question 1

physcial methods of controlling microbial growth

Answer 1

heat
filtration
dessication
radiation

Question 2

chemical methods of controlling microbial growth

Answer 2

inanimate objects
animate objects

Question 3

what is sterilization

Answer 3

destruction of all life forms
commercial sterilization
autoclaving- 1210 C at 15-17 psi
chemical- ethylene oxide
glutaraldehyde

Question 4

what is disinfection

Answer 4

destruction of pathogen
pasteurization

Question 5

what is a disinfectant

Answer 5

disinfection of inanimate objects

Question 6

what is antiseptic

Answer 6

disinfection of animate objects

Question 7

what is sanitization

Answer 7

reduction to safe levels

Question 8

what is degerming

Answer 8

mechanical

Question 9

what is stasis

Answer 9

static- prevent growth

Question 10

what is cidal

Answer 10

to kill

Question 11

what is death rate

Answer 11

cumulative time to kill 90% of organisms
measured as D value
effectiveness of procedure

Question 12

what are parameters affecting microbial death

Answer 12

quantity of microorganisms present
presence of organic matter
length of exposure
microbial characteristica

Question 13

what are the mechanisms of microbial agents

Answer 13

plasma mebrane leakage
protein denaturing
nucleic acids mutation (radiation)

Question 14

what are some physical antimicrobial methods

Answer 14

heat
denaturing for moist heat and pasteurization
oxidation for dry heat and flaming

Question 15

what is dessication

Answer 15

dehydrators
organisms need water
organisms cannot grow but can remain viable for years

Question 16

what is filtration

Answer 16

physically remove
membrane filters < 1 micrometer
HEPA- removes microorganisms larger than 0.3 micrometers
reverse osmosis filtered with pressure
ultrafilttration

Question 17

what is radiation

Answer 17

mutates DNA
not always harmful
ionizing- short wavelengths- x-rays and gamma
non-ionizing- UV and air and water sterilization
effective t controlling growth

Question 18

what effect does freezing have on organisms

Answer 18

static effect
slows down growth

Question 19

what are examples of osmotic pressure

Answer 19

pcikling and curing

Question 20

considerations for chemical methods of controlling growth in-vitro

Answer 20

some for inanimate objects only
rough surfaces harder than smooth surfaces to control- skin considered a rough surface

Question 21

chemical methods for controlling growth in-vitro

Answer 21

phenols and phenolics
Lister
denatures proteins
disrupts membranes
ex. lysol
very good/toxic

Question 22

alcohol for controlling growth in-vitro

Answer 22

not very effective against spores and viruses
denatures proteins
disrupts membranes
70% IPA

Question 23

what is a halogen

Answer 23

strong oxidizer-denatures proteins
ex. chlorine and iodine

Question 24

what is an oxidizing agent

Answer 24

strong oxidizer denatures proteins
ex. hydrogen peroxide and ozone

Question 25

what are surfactants

Answer 25

do not denature proteins
cationic surfactants- decrease surface tension and disrupts cell membranes
colorless, tasteless, and relatively harmless
food preservatives
ex. benzalkonium chloride

Question 26

what are aldehydes

Answer 26

denatures proteins
ex formaldehyde