Controlling Microbial Growth- PP Test 2 Flashcards
the destruction or removal of vegetative pathogens but not bacterial endospores, usually used on inanimate objects
disinfection
the complete removal or destruction of all viable microorganisms, used on inanimate objects
sterilization
chemicals applied to body surfaces to destroy or inhibit vegetative pathogens
antisepsis
chemicals used internally to kill or inhibit growth of microorganism swithout host tissues
chemotherapy
What are the different types of microbial control methods?
physical agents, chemical agents, biological agents, and mechanical removal methods
What are the different types of physical agents?
Heat and radiation
What are the different types of heat physical agents?
dry and moist
What type of control method does dry heat have?
incineration and dry oven which are both sterilization methods
What type of control method does moist heat have?
steam under pressure which is sterilization and boiling water, hot water, and pasteurization which all are disinfection
What are different types of radiation physical agents?
ionizing and xray, cathode, and gamma which are sterilization and nonionizing and uv which are disinfection
What are the different types of chemical agents?
gases and liquids
What are the different types of gas chemical agents?
gas can be sterilization and or disinfection
What are the different types of liquid chemical agents?
animate which is chemotherapy and antisepsis and inanimate which are disinfection and sterilization
What are the different types of mechanical removal methods?
filtration which consist of air and liquids which both are sterilization
What are the different types of biological agents?
predator and virus which are antisepsis and toxin which is sterilization
sufficient heat treatment to kill endospores of clostridium botulinum in canned food
commercial sterilization
removal of microbes from a limited area, such as skin around an injection site
degerming
treatment is intended to lower microbial counts on eating and drinking utensils to safe public health levels
sanitization
inhibits growth and when you remove it the microbes can start growing again (freezer) can usually work very well you can kill cells using this technique but the technique itself does not kill
bacteriostatic
kill the microbes so viable cell count decreases when you introduce the chemical but the total cell count does not decrease because the cells are still there
bactericidal
lose the microbe decrease in cell count and viable cell count because nothing is growing and the cells are broken, very lethal
bacteriolytic
What is the most widely used method of sterilization?
Temperature
amount of time required at given temperature to reduce viability, exponential relationship, heat kills faster as temperature rises, and moist heat penetrates better than dry heat
decimal reduction time (D)
time to kill all cells at a given temperature, affected by population size
thermal death time
What can survive heat that would rapidly kill vegetative cells?
endospores
Statistically you can feel safe that you have destroyed the microbes but they never get to…
zero
The higher the temp the what?
the more lethal and the less time it takes
increasing temperature and pressure to sterilize different things inside a chamber, you can kill things all the way up to endospores, advantages are that you can sterilize anything you put in there, plastic and metals cannot withstand the temperature, you alter the time not the temp, the more things in there the longer it takes
autoclave and moist heat sterilization
for food based products, heating liquids to a certain temperature to inhibit the growth of pathogenic microorganisms, the lower the ph the harder for microbes to grow
pasteurization
What can cause DNA to bind to each other instead of there complimentary which during DNA replication mutations can more easily occur
UV light
sterilizes but does not go very deep into tissues
nonionized radiation
can cause damage to DNA and has the ability to go deep into tissues, can be used on anything that is heat sensitive
ionized radiation
filtration used on heat sensitive liquids and gases, pores of filter are too small for living organisms to pass through but do not trap most viruses
Microbiological filters
fibrous sheet made of overlapping paper or glass fibers that traps particles
depth filters
most common for liquid sterilization, high strength polymers with many tiny pores, and syringe or pump forces liquid into sterile vessel
membrane filters
disrupt the membrane and denature proteins
phenol and phenolics
very good detergents, really good with destroying membranes, not as effective as alcohol
quaternary ammonium compounds
really good oxidizers, all have some sort of antimicrobial effect, mot persistent toxins
halogens
most destroy membranes
alcohol
toxic to everything, they will oxidize proteins and materials in the cell, effect different kinds of proteins, most are microbial static, when removed microbes can grow again, different of these will inhibit microbial growth but the risk factors are awful
heavy metals
they will often inhibit the growth and are usually more clean because they are more easily cleaned
manufactured surfaces
What on cicada wings pull bacterial membranes apart
antibacterial nanopillars
What inspired antibacterial surfaces for corneal transplant
insect wings
oxidize proteins, can be converted into a gas and can be used as a delicate chemical sterilant
hydrogen peroxide
highly reactive molecules, sporicidal and can be used as chemical sterilant, combine with and inactivate nucleic acids and proteins
aldehydes and hydrogen peroxide
used to sterilize heat-sensitive materials, can be used as sterilants and are oxidizing agents
sterilizing gases
newer, use hydrogen peroxide gas, can be used to sterilize electronic equipment, a lot of times its used when putting electrical equipment in somebodies body
plasma sterilizers
emerging as transplant tissue sterilization option
supercritical carbon dioxide
What are the conditions influencing the effectiveness of antimicrobial agent activity
population size, population composition, concentration/intensity of an agent, contact time, temperature, local environment
keep in context how many microbes you are tryin gto eliminate
population size
different types and there susceptibility
population composition
similar to size
concentration
the longer you have something exposed the more microbial inhibition and microbial death
contact time
the higher temperature the faster decimal reduction rate
temperature
how much organic material present, what is the ph, what is the pressure, and what is the humidity
local environment
