Exercise 2-12 Micro Lab: Steam Sterilization
substances or systems, chemical or physical, used to prevent the spread of pathogens
targeting a wide variety of pathogens
3 categories germicidal systems fall into
reduction of pathogenic microorganisms to a level at which items are safe to handle without protective attire
__________ is the lowest level of control
Decontamination usually includes what? (2)
1. physical cleaning with soaps or detergents
2. removal of all (ideally) or most organic and inorganic material
_______ is considered the critical first step toward disinfection or sterilization because _______
proper cleaning of all instruments and surfaces
to be fully effective, a disinfectant or sterilant must come in direct contact with all pathogens present. materials left to dry on a surface or apparatus can actually shield pathogens from a disinfecting or sterilizing agent or otherwise neutralize it.
kills large numbers, if not all, of the targeted pathogens but typically do not kill large numbers of spores
Why are some disinfectants called chemical sterilants?
because they have the ability to kill all vegetative cells and spores
complete elimination of viable organisms including spores and, as such, is the highest level of pathogen control
6 methods of disinfection
1. liquid chemical agents
4. dry heat
5. moist heat
6. ultraviolet light
9 methods of sterilization
4. dry heat
5. moist heat
6. ethyline oxide gas
7. ionizing radiation
8. low temperature plasma
9. low temperature ozone
3 types of ionizing radiation
low temperature plasma
utilizing a combination of chemical sterilants and ultraviolet radiation in a vacuum chamber
low temperature ozone
utilizing bottled oxygen, water, and electricity in a chamber
_____ is the most effective and most common means of sterlization
the device used for steam sterlization
How does an autoclave work?
it uses super heated steam under pressure to kill heat resistant organisms
3 examples of heat resistant organisms
Sterilization temperature is usually set between _____ and _____
121-127 degrees Celsius
How long to steam?
test systems that contain something living.
the only way to make sure that sterilization is complete
one way of telling if sterilization is complete is through ______________
color coded autoclave tape (grey is autoclaved, blue is not autoclaved)
the dominant form of an organism that is highly resistant to both chemical and physical means of control
if an autoclave kills these, it is safe to say it will kill everything else microbially
A vial turns from _______ color to ______ color when it is autoclaved. What do the two colors mean?
yellow to purple. yellow is not autoclaved (evidenced by blue band of color strip too) and fermentation/acid production is in the medium. the organism is alive. The purple is autoclaved (evidenced by grey strip) and there is no fermentation/acid production in the medium. the organism is dead.