Unit 19 Flashcards
Sterilization
Killing ALL microbes
Disinfection
Removal of vegetative of pathogens from inanimate objects
Sanitization
Reduction in number of microbes from inanimate objects present to safe public health levels
By mechanical cleaning and physical methods
Sepsis
Growth of microbes (presence of toxins) in tissue
Asepsis
Techniques that prevent the entry of microorganism a into sterile tissue
Antisepsis
Application of chemicals to body surfaces to kill or inhibit microbes
Does not cause damage to tissue
Aseptic technique
Methods applied to an object or area to prevent microbial (pathogenic) contamination
Degerming
Cleansing techniques to remove transient microbes and debris from living tissue
Bactericide
Chemicals that kill vegetative cells and may not kill the spores
Bacteriostat
Chemicals that stop or slow microbial growth
Factors influencing control
# of microorganisms Type of " Nature of suspending medium -determine nature of the chemicals Time and Temp.
Types of Cellular Injury
Alteration of membrane permeability
-damage to cell wall and membrane
Damage to proteins
Damage to nucleic acids
Physical methods
Heat, low temp., desiccation, radiation, filtration, osmotic pressure, physical cleaning
Heat
Most common method
Most effective
Least expensive
Heat mode of action
Denaturing protiens by coagulation
Oxidizing of microorganisms
Heat resistance varies
Amongst microbes
Thermal Death point (TDP)
Lowest temperature at which all the microorganisms in a liquid suspension will be killed in 10 minutes
Thermal Death Time (TDT)
Minimal length of time for all the microorganisms in a liquid suspension to be killed at a given temp.
Autoclave - moist heat
Steam under pressure 121 C at 15 psi for 15-20 min Sterilization Test by: spore strips Heat sensitive tapes
Boiling
98-100 C for 30 min
Kills most vegetative cells, not heat resistant forms
Tyndallization (Fractional Sterilization) - moist heat
Heating 100 C for 30 min
For 3 days
With over night incubation periods in between
Pasteurization - Moist Heat
Heating materials at specific temp. And time
Then cool rapidly
Temp. Selection is based upon resistant pathogen to be destroyed
- Coxiella Burnetti
Past. - High Temp. short term ( HTST)
72 C for 15 sec.
Ultra high temp. (UHT) - Pasteur.
140 C for 1-2 sec.
