Module 3 Flashcards
Sterilization
The process of destroying all forms of microbial life on an object or in a material
It’s absolute
Disinfection
The process of destroying vegetative pathogens, but not necessarily endospores or viruses
Typically a chemical applied to an object or a material
Tend to reduce or inhibit growth. Does not sterilize
Antisepsis
Chemical disinfection of the skin, mucous membranes, or other living tissues
Germicide
A chemical agent that rapidly kills microbes but not necessarily their endospores
Bacteriostasis
Condition in which bacterial growth and multiplication are inhibited, but the bacteria are not killed
If the bacteriostatic agent is removed, bacterial growth and multiplication may resume
Asepsis
The absence if pathogens from an object or area. Aseptic techniques are designed to prevent the entry of pathogens into the body
Degerming
The removal of transient microbes from the skin by mechanical cleansing or by the use of an antiseptic
Sanitization
The reduction of pathogens to safe public health levels on eating utensils by mechanical cleaning or chemicals
Moist heat sterilization
Boiling or flowing steam
Denaturation- kills vegetative bacterial and fungal pathogens and many viruses within 10 minutes. Less effective on endospores
Autoclaving
Denaturation- very effective method of sterilization. All vegetative cells and their endospores are killed in about 15 minutes
Dry heat
Direction flaming
Burning to ashes- very effective method of sterilization
Incineration
Burning to ashes- very effective method of sterilization
Hot-air sterilization
Oxidation–ashes- very effective method of sterilization, but requires temp of 170C for 2 hours
Pasteurization
Denaturation- heat treatment for milk (72C fir about 15 seconds) that kills all pathogens and some non-pathogens
Filtration
Separation of bacteria from suspending liquid
Passage of a liquid or gas through a screen-like material that traps microbes
Most filters consist of cellulose acetate or nitrocellulose
First phase of water filtration
Low temperature
Refrigeration
Decreased chemical reactions– has a bacteriostatic effect
Not good after 72 hours
Deep-freezing
Decreased chemical reactions- an effective method for preserving microbial culture, in which cultures are quick-frozen between -50C and -95C
Lyophilization
Decreased chemical reactions- most effective method for long-term preservation of microbial cultures, water removed by high vacuum at low temperatures
Can freeze, thaw, and reuse it
Desiccation
Disruption of metabolism- involved removing water from microbes primarily bacteriostatic
Osmotic pressure
Plasmolysis- results in microbial cell lysis
