The complete elimination of all lifeforms, including endospores.
The elimination of all vegetative cells of pathogens.
Disinfection - does not include non-pathogenic cells
The reduction of pathogens to a "safe" level.
What are the substances used for cleaning microbes?
Sterilants, Disinfectants, and Sanitizers
Disinfectants that have been approved for use on the body?
What is the mechanism of action?
The specific way the methold accomplishes the killing or inhibition
What are the three most common mechanisms of action?
Damage to proteins and DNA, altering of membrane permeability, and slowing down metabolism
What does damage to proteins and DNA include? What do they result in usually?
Wet heat (denatures proteins), heavy metals (interfere with protein function), and radiation (damages DNA) - death
What does altering membrane permeability include? What usually results?
Phenolics and quaternary ammonium compounds, both of which insert themselves into the cell membrane and form hole that ruin the membrane's intergrity - damage causes them to become leaky, which causes loss of nutrients or entry of undesirable substances
What does slowing down metabolism include? What does that result in?
Bacteriostatic (slows down instead of kills) cold and desiccation (drying) - it stops reproduction
Methods of controlling bacterial growth can be what?
Physical or Chemical
Physical methods of controlling bacterial growth alter what? They include what?
Environment - the use of heat, cold, radiation, desiccation, osmotic pressure, filtration, and soaps & detergents
Chemical methods of controlling bacterial growth employ what? This includes what?
Some type of chemical attack - phenolics, halogens, alcohols, heavy metals, aldehydes, quaternary ammonium compounds, and peroxides
Moist heat (hot water or steam) use what mechanism of action?
What are some methods of Moist Heat?
Boiling, Autoclaving, and Pasteurization
Endospores usually survive what type of mechanism of action?
Boiling (especially if it is under 10 minutes)
How do autoclaves work? What are they used for?
They use steam under pressure - Used to sterilize microbiological media and medical supplies
What is the most common time and temperature used in autoclaving?
121 degrees Celsius (15 psi) for 15 minutes
What is the target organism for the pasteurization of milk?
What are some other forms of autoclaves?
Commerical and Home Canners (pressure cookers)
What are commercial canners called? What is their canning process called?
Retorts - Commerical Sterilization
What is the target organism of commercial canning?
Endospores of Clostridium botulinum
Home canners should be operated at what temp/time?
121 C for 15 minuts
What is the most common cause of botulism?
Inadequately processed home canned foods
What is Dry Heat's mechanism of action?
Kills by burning
What is an example of Dry Heat (Fire of Hot Air)?
incineration or hot air
Dry heat is less/more effective than moist heat at the same temperatures?
What is the most common time and temperature used to sterilize with hot air?
160 degrees Celsius for 120 minutes
Dry heat sterilization is usually used for what and why?
Glass or Metal objects - high temperatures
Why do some hospitals have their own incinerators?
To burn their biological wastes
What are done with the carcasses of cattle infected with anthrax?
They are often incinerated to make sure the endospores are destroyed
What is anthrax caused by?
What is a method of dry heat we use in lab?
Flaming our loops (incineration)
What is the mechanism of action for Cold?
What is an example of Cold?
Freezing and Refrigeration
Cold temperatures are what to cells?
Bacteriostatic (inhibit growth)
Bacteriocidal means? Bacteriostatic?
Kills cells, Slows them down
How is the growth of most Mesophiles inhibited?
What is an example of a Mesophile that its growth cannot be inhibited by refrigerator temperatures?
Psychrotrophs grow at what temperatures and are responsible for what?