Chapter 9 Flashcards
Completely destroys all forms of microbial life
Sterilization
Limited heat treatment, destroys pathogens but not all bacteria
Commercial Sterilization
Destroys vegetative cells on a surface; reduces # of a viable organisms in/on the material
Disinfection
chemical treatment used to disinfect inanimate objects
Disinfectant
treatment of living skin or tissue to kill microorganisms
Antisepsis
physical removal of microbes (alcohol swab, soap)
degerming
systematic cleansing of inanimate object to reduce the microbial count to a safe level (for public health, used in restrooms, kitchens)
Sanitize
kill all bacteria
Bacteriocidal (-cidal, to kill)
halt (inhibit) the growth of bacterial for a long as the inhibitory substances is present - if inhibitor is removed, growth begins again
Bacteriostatic (-static, to stop)
lowest temperature that kills all cells in broth in 10 minutes
(TDP) Thermal death point
Time to sterilize volume of liquid at set temperature
(TDT) Thermal death time
can be used with endospore-forming bacteria
Tyndallization
steam alone can reach 100 oC, but under pressure (15psi) can reach 121oC - kills Bacillus stearothermophilus endospores in 15 minutes at this temperature
Autoclaving
uses temperature below boiling to kill pathogens (brucella melitensis) reduces total microorganisms count (doesn’t kill all, some harmless microorganisms survive), does not alter food taste - used for milk, ice cream, yogurt, and fruit juices
Pasteurization
63oC for 30 minutes
Classical Pasteurization
now use high-temperature short-time 72oC for 15 seconds . sometimes called high temperature short time (HTST) pasteurization
Flash Pasteurization
- 140oC for 1 sec, then rapid cooling
- treated liquids can be stored at room temperature
Ultrahigh-temperature sterilization
including flaming mouth of tubes, inoculating loops/needles - empty glassware can be sterilized in oven in 1-3 hours at 180oC
Aseptic techniques
is ultimate means of sterilization
incineration
for long-term preservation of microbial cultures
Lyophilization
UV ligh causes ______in DNA
pyrimidine dimers
effective at killing but do not penetrate well
Electron beams
penetrate well but requires hours to kill microbes (gamma radiation from cobalt-60)
Gamma Rays
was the first chemical used to control microorganisms by joseph lister; used as disinfectants and antiseptics
Phenol
most used alcohols - used most (at 70-80% concentrations)
Ethanol and isopropanol
Types of Halogens
Betadine, iodine, Chlorine
can disinfect and sterilize surfaces
Peroxides (hydrogen peroxide)
have hydrophilic and hydrophobic ends (good degerming/disinfecting agents but not antimicrobial)
Soaps & detergents
Low-level disinfectants ideal for many medical and industrial applications
Quats
Some contain antibacterial agents such as _____ (effective against G+)
Triclocarbon
used to preserve vaccines
Thimerosal
controls algal growth
Copper
is a Perservative
Formaldehyde
disinfects and sterilizes
Glutaraldehyde
used in embalming and disinfection of rooms and instruments
Formalin
