ch 7 Flashcards
autoclave
steam heat under pressure- steam must contact item’s surface
pasteurization
reduce, not sterilize spoilage organisms
high temp for a short time
-ultra past.- very high temp for even shorter time
dry heat/ flamming
kills by oxidation
biocide/germicide
kills microbes
bacteriostasis
inhibiting, not killing microbes
asepsis
the absence of significant contamination
sterilization
removing all microbial life
disinfection
removing pathogens
degerming
removing microbes from a limited area
sanitization
lowering microbial counts on eating utensils
filtration
decreases number of microbes based on size of microbes, used when you can’t use heat
low temp
inhibits microbial growth- refridgeration, deep freeze, lyophilization
high pressure
denatures proteins
desiccation
prevents metabolism
osmotic pressure
causes plamolysis
microbial death curve
kill 90%
how does radiation kill cells
damages the DNA- ionizing and nonionizing
List the 4 factors related to effective disinfection
- concentration of disinfectant
- organic matter
- pH
- time
interpret the results of the disk-diffusion method
will have a zone of inhibition- does not kill microbes, just slows the growth
list the most to least resistant microbes (1-5)
- prions
- endospores of bacteria
- mycobacteria
- cysts of protozoa
- vegitative protozoa
list the most to least resistant microbes (6-10)
- gram-neg bacteria
- fungi (including spores)
- vius w envelopes
- gram pos bacteria
- virus w lipid envelopes
which is best way to get rid of microbes
sterilization- moist heat
thermal death point
lowest temp at which all cells in a culture are killed in 10 min
thermal death time
time during which all cells in a culture are killed
decimal reduction time
min to kill 90% of a population at a given temp
triclosan
a bisphenol (disrupts plasma membranes)
