chapter 9 Flashcards
(41 cards)
sterilization
- cannot destroy endospores
- destroys viable microorganisms and viruses
commercial sterilization
destroys viable microorganisms, viruses, and endospores
- food processing
- mainly for spores of clistridium botilinum
disinfection
destroys microorganisms
- non-living surfaces
decontamination/sterilization
removes microorganisms
- food industry utensils
antisepsis
- kills microorganisms
-inhibits microbial growth - applied to skin
degerming
removal of microorganisms
handwashing
level of resistance of microbial types from most to least
PBMSPPMFNME
prions
bacterial endospores
mycobacterium
staphylococcus and pseudomonas
protozoan trophozoites
most gram - bacteria
fungi and fungal spores
most gram + bacteria
enveloped viruses
what affects the cell wall
chemicals, detergents, and alcohol
what affects the cell membrane
detergents
what affects cellular synthesis
heat, radiation, formaldehyde, and ethylene oxide
what affects proteins
ethylene oxide, filtration, moist heat, alcohol, phenolics
what do surfactants do to the cell wall
decrease level of surface tension so bacteria can be released
degree of heat for moist heat to be effective
60-135 degrees C
degree for dry heat to be effective
over 1,000 degrees C
steam sterilization heat and PSI for how long?
121C = 15 PSI for 15 mins
NaOH destroys prions what what temp for how long
134 degrees C for 2 hours
vegetative cells death times and temps vary from…
50 degrees C for 3 mins to
60 degrees C for 60 mins
viruses tolerance to heat
from 55 degrees C for 2-5 mins to 60 degrees C for 600 minutes
thermal death time
the time it takes for 100% of microbes to be dead
thermal death point
lowest temp it takes to kill all microbes in 10 mins
what does glycerol do when its added to bacteria
stabilizes the cell membrane
psychrotrophs can survive at …
15-30 degrees C
psychrophiles can survive at temps less than…
15 degrees C
examples of psycrotrophs
S. aureus
Clostridium
Streptococcus
Slamonella
Yeasts, molds, viruses
