Microbial Growth

Question 1

sterile

Answer 1

destruction of all microbes and viruses (not prions)

Question 2

disinfected

Answer 2

destruction of most microbes (usually pathogens) on inanimate objects

Question 3

antiseptic

Answer 3

disinfection on living tissue

Question 4

pasteurization

Answer 4

use of heat to disinfect food items

Question 5

degerming

Answer 5

mechanical destruction of microbes from the skin (hand washing, alcohol swabs)

Question 6

sanitation

Answer 6

meet public health stnadards

Question 7

most resistant to least resistant microbes

Answer 7

prions, endospores, mycobacteria

enveloped viruses, G+ bacteria, nonenveloped viruses

Question 8

moist heat

Answer 8

disinfects, sanitizes, sterilizes

Question 9

autoclave

Answer 9

sterilizes

can kill prions with increased time

Question 10

pasteurization

Answer 10

disinfects
used on dairy
flash, batch, or uht
heat resistant bacteria survive

Question 11

UHT treatments

Answer 11

decreases nutrients
oxidizes
used on almond/soy milk, makes shelf stable

Question 12

boiling

Answer 12

disinfects

doesn’t kill endospores, viruses, cysts

Question 13

dry heat

Answer 13

for surgical and sharp items, would oxidize in moisture
denatures proteins
ovens, slower than moist heat

Question 14

incineration

Answer 14

sterilizes

Question 15

drying- dessication

Answer 15

dehydration, removal of water

Question 16

drying- lyophilization

Answer 16

preserves cultures, solid -> vapor, no ice crystals

“freeze-dried”

Question 17

filtration

Answer 17

membrane filters or HEPA filters (lab hood)

Question 18

electron beams

Answer 18

kill on the surface, don’t penetrate

Question 19

gamma rays

Answer 19

penetrate, takes hours to kill

Question 20

ionizing radiation

Answer 20

< 1nm wavelength
for heat sensitive materials and foods
ions break bonds

Question 21

UV light

Answer 21

disinfect
more than 1nm, UV = 365nm
makes pyrimidine dimers in DNA, affects 3D structure
doesn’t penetrate
disinfects air, transparent fluids, object surfaces

Question 22

phenols

Answer 22

low level disinfectants
work on organic compounds
denature proteins, destroys cell membranes
chlorinated phenols: used in labs, hospitals, some homes, but odor and side effects for babies
lysol

Question 23

alcohols

Answer 23

intermediate level disinfectants
denature proteins, destroy cell membranes
best at 70%, swab used before injections

Question 24

halogens

Answer 24

intermediate level disinfectants
damage enzymes by oxidation and denaturing
iodine tablets
chlorine bleach, treated water
might have carcinogenic bi-products

Question 25

oxidizing agents

Answer 25

high level disinfectants
oxidize enzymes
peroxides: disinfect, sterilize
ozone: treatment of drinking water, expensive
peracetic acid: sporocide, sterilize equipment

Question 26

surfactants

Answer 26

degerming, low level disinfectants
decrease surface tension of solvents
positively charged
quaternary ammonium compounds (quats): low level

Question 27

heavy metals

Answer 27

low level disinfectants
denature proteins
silver nitrate: prevents gonorrhea blindness
mercury, selenium, copper

Question 28

alkylating agents

Answer 28

sterilize
agglutinate fatty acids, toxic in high concentrations
formaldehyde/glutaraldehyde: embalming, disinfect / sterilize
ethylene oxide gas: closed chamber sterilization, no longer used