Microbial Growth Flashcards
sterile
destruction of all microbes and viruses (not prions)
disinfected
destruction of most microbes (usually pathogens) on inanimate objects
antiseptic
disinfection on living tissue
pasteurization
use of heat to disinfect food items
degerming
mechanical destruction of microbes from the skin (hand washing, alcohol swabs)
sanitation
meet public health stnadards
most resistant to least resistant microbes
prions, endospores, mycobacteria
enveloped viruses, G+ bacteria, nonenveloped viruses
moist heat
disinfects, sanitizes, sterilizes
autoclave
sterilizes
can kill prions with increased time
pasteurization
disinfects
used on dairy
flash, batch, or uht
heat resistant bacteria survive
UHT treatments
decreases nutrients
oxidizes
used on almond/soy milk, makes shelf stable
boiling
disinfects
doesn’t kill endospores, viruses, cysts
dry heat
for surgical and sharp items, would oxidize in moisture
denatures proteins
ovens, slower than moist heat
incineration
sterilizes
drying- dessication
dehydration, removal of water
drying- lyophilization
preserves cultures, solid -> vapor, no ice crystals
“freeze-dried”
filtration
membrane filters or HEPA filters (lab hood)
electron beams
kill on the surface, don’t penetrate
gamma rays
penetrate, takes hours to kill
ionizing radiation
< 1nm wavelength
for heat sensitive materials and foods
ions break bonds
UV light
disinfect
more than 1nm, UV = 365nm
makes pyrimidine dimers in DNA, affects 3D structure
doesn’t penetrate
disinfects air, transparent fluids, object surfaces
phenols
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
alcohols
intermediate level disinfectants
denature proteins, destroy cell membranes
best at 70%, swab used before injections
halogens
intermediate level disinfectants damage enzymes by oxidation and denaturing iodine tablets chlorine bleach, treated water might have carcinogenic bi-products
oxidizing agents
high level disinfectants
oxidize enzymes
peroxides: disinfect, sterilize
ozone: treatment of drinking water, expensive
peracetic acid: sporocide, sterilize equipment
surfactants
degerming, low level disinfectants
decrease surface tension of solvents
positively charged
quaternary ammonium compounds (quats): low level
heavy metals
low level disinfectants
denature proteins
silver nitrate: prevents gonorrhea blindness
mercury, selenium, copper
alkylating agents
sterilize
agglutinate fatty acids, toxic in high concentrations
formaldehyde/glutaraldehyde: embalming, disinfect / sterilize
ethylene oxide gas: closed chamber sterilization, no longer used
