Chapter 13 Flashcards
septic
with growth`
aseptic
absence of significant contamination
fomites
inanimate objects that can spread disease
disinfectant
chemical/physical methods to reduce organism growth
to kill fomites..
use disinfectant, sanitization, or sterilization
antiseptics
do the same as disinfectants but on living tissue (skin)
sanitization
used with eating utensils
degerming
physical/mechanical removal of microbes (handwashing)
on living tissue
sterilization
killing all microbial growth (aseptic lab techniques)
commercial sterilization
does not sterilize
kills c.diff in canned foods
thermal death point
the temp that will kill all microbes in a sample in 10 mins
thermal death time
how long it takes to kill all microbes at a given temp
is dry heat or moist heat more effective?
moist heat
moist heat
used for cooking, not for lab
will not kill endospores (c.diff)
dry heat
takes longer
170 degrees C for 2 hours
ovens
incineration
destroys by oxidizing (flaming wire loop)
autoclave is using…
moist heat
how does an autoclave work to kill microbes
uses pressurized steam to kill microbes and their ENDOSPORES
autoclave temp
121 C for 15 mins @ 15 lbs psi
how is steam effective towards microbes
it must come into direct contact in order to kill
what does pasteurization do?
kills pathogens
reduces food spoilage organisms
what is the exception with autoclaves
prions, they cause mad cow disease
pasteurization
prevents spoilage
does not sterilize
with pasteurization, the temp goes ______, the time goes _______
up, down
what are the different types of pasteurization?
stove top past.
HTST past (high temp short time)
UHT past (ultra high temp)
HEPA filtration is used on…
air (0.3 picometer pore size)
membrane filtration is used on…
liquids and heat-sensitive organisms
filtration is important for
vaccines
Refrigeration
bacteriostatic –> keeps microbes from growing and inhibits metabolism
freezing inhibits…
some microbes and kills others
pascalization
high pressure to control microbes
preserves food
takes 100-800MPa
desiccation
drying, sucks water out, slowing metabolism
not sterile
canned goods use a process called
plasmolysis
hypertonic environment is used for what…
honey and jam
plasmolysis
is the loss of water that occurs when a bacterial cell is put in a hypotonic environment
lyophilization
freeze drying
Ionizing vs non-ionizing radiation
ionizing: more powerful
non-ionizing: only useful on surfaces
ionizing radiation
x-rays and gamma rays
damages double helix DNA
penetrates surfaces
radura
put on foods that have been “electronically pasteurized”
non-ionizing radiation
UV light
causes thymine dimers
only useful on surfaces
kirby bauer antibiotic testing method
cover whole plate with bacteria and look for clear zones where it should tell you whether an organism is sensitive or resistant to an antibiotic
how do phenolics and bisphenols kill microbes
by denaturing proteins and disrupting membranes
phenolics replaced phenol because…
1) more effective
2) less toxic
3) less irritating
4) more stable
5) persist on surfaces
o-phenylphenol
phenolic
active ingredient in lysol
what works in the presence of organic materials? (blood, puke, etc)
o-phenylphenol
triclosan is…
a bisphenol
triclosan is ____ of liquid hand soap and _____ of bar soap
75%, 30%
what does triclosan harm?
immune function
endocrine function
reproductive health
how does chlorhexidine kill microbes
disrupts cell membranes
example of triclosan resistant organisms
salmonella enterica
chlorhexidine is a key…
bisbiguanide
chlorhexidine is used as…
1) surgical hand scrub
2) surgery prep soap
3) oral rinse
what is faster acting than chlorhexidine
alexidine
how do alcohols kill microbes
denatures proteins and disrupts plasma membrane
what is the most effective alcohol concentration?
70%
surfactants
in soaps and detergent
soap
don’t kill microbes, they physically remove them (degerming)
QUATS are more common in…
healthcare
toxic forms of oxygen
free radicals (reactive oxygen species)
How do peroxygens work for microbial control?
they oxidize and create free radicals
peracetic acid (PAA)
more effective than hydrogen peroxide at killing endospores
benzoyl peroxide
used in acne meds to kill propionibacterium acnes
hydrogen peroxide is used as…
a disinfectant, antiseptic, or gas
carbamide peroxide
used in toothpaste to inhibit strep and disrupt biofilms
ozone (O3)
used in water treatment
How do alkylating agents work?
inactivates enzymes and nucleic acid
formalin is..
37% formaldehyde
chloramines are useful because…
they release chlorine over longer periods of time
more stable
how do halogens work with microbial control
they oxidize and destabilizes cellular macromolecules
chlorine forms _______________ in water
hypochlorous acid
oligodynamic action
the ability of small amounts of a heavy metal compound to exert antimicrobial activity
supercritical fluids
have properties of liquids and gases
plasma is a good way to sterilize….
tubular instruments
how do supercritical fluids work?
they penetrate cells, form carbonic acid, and lowers intracellular pH
plasma is the _____________
4th state of matter
