55 terms

microbiology ch7

study outline key facts chapter 7
infections and food spoilage
control of microbial growth can prevent -------- and ------
the process of removing or destroying all microbial life on an object
commercial sterilization
heat treatment of canned foods to destroy C. botulinum endospores
process of reducing or inhibiting microbial growth on a non living surface (animated)
process of reducing or inhibiting microorganisms on living tissue
"Cide" means kills
"Stat" means inhibits
suffix "cide" means
suffix "stat" means
sepsis (contamination); Asepsis (absence of contamination)
bacterial contamination is called?
absence of contamination is called?
microbial control done by steam under pressure or ethylene oxide gas; destroys/removes microbial life including endospores
commercial sterilization
microbial control by stopping germination and growth of more resistant endospores of thermophilic bacteria that may survive under normal storage conditions like in canning
disinfection: chemical agent disinfectant
microbial control that may make use of physical or chemical methods, destroys vegetative (non endosporing) pathogens
antisepsis; chemical agent: antiseptic
microbial control; treatment is almost always antimicrobials, destroys vegetative (non endosporing) pathogens on living tissue
degerming (degermination)
microbial control; mostly mechanical removal by alcohol swabbing at injection site or limited area
microbial control: done by high temperature wash or dipping in chemical disinfectant: public health
Intends to lower microbial count on eating and drinking utensil to safe public health level
commercial sterilization; clostridium botulinum
sufficient heat treatment to kill endospores in canned food name microbial growth method and bacterium.
a sterilizing agent is called
biocide, germicide means kill microorganisms
fungicide means kill fungi
biocide, germicide kills?
fungicide kills?
a constant rate
Bacterial populations subjected to heat or antimicrobial chemicals usually die at ____
straight line
microbes dying at constant rate the death curve when plotted logarith shows this constant death rate as a
the number of microbes
the time it takes to kill a microbial population is proportional to
microbial species and life cycle phases of endospores & others like them
these have different suseptibilities to physical and chemical controls
Physical and chemical controls
microbial species and life cycle phases (ie endospores), have different suseptibilities to -----
Organic matter
factors that influence antimicrobial treatments:
can interfere with heat treatments and chemical control agents
shorter time at higher heat
factors that influence antimicrobial treatments: Longer exposure to lower heat can produce the same effect as
1. Number of microbes
2. enviromental
3. time of exposure
4. microbial characteristics
factors that influence antimicrobial treatments:
list factors that influence the effectiveness of antimicrobial treatments:(4)
Longer than lower population, the more microbes the longer it takes
factors that influence antimicrobial treatments: Between a high population and a low population if the kill rate is the same, the high population will take longer or shorter?
chemical agents
factors that influence antimicrobial treatments:Hospitals are selective because the presence of organic matter such as (vomit, feces, blood) inhibits --------
surface biofilms
factors that influence antimicrobial treatments:biocides to kill microbes are difficult to reach effectively when in
factors that influence antimicrobial treatments:Because their activity is due to temperature dependent chemical reactions microbes in surface biofilms are difficult to reach by
warmer conditions such as warm water
factors that influence antimicrobial treatments:disinfectant work better under what conditions; direction frequently specify
factors that influence antimicrobial treatments: heat is more effective under what conditions?
Heat treatment
factors that influence antimicrobial treatments: the nature of the suspending medium is also a factor in what treatment?
fats and proteins; like oils on your hands.
factors that influence antimicrobial treatments: microbe will have a higher survival rate if a suspending medium is rich with
fats and proteins
factors that influence antimicrobial treatments: A medium rich with these substances will protect microbes
microbes and endospores
factors that influence antimicrobial treatments: Chemical antimicrobials often require extended exposure in order to be effective against?
factors that influence antimicrobial treatments: In heat treatments a longer exposure can compensate for a lower temperature, a phenomenon particularly important in ________
plasma membrane permeability and damage to proteins and nucleic acids
factors that influence antimicrobial treatments: microbes can be controled by their charateristics such as _______ and ________
Lipid and protein
The suseptibility of the plasma membrane is due to what components?
certain chemical control agents damage the plasma membrane by altering its?
hydrogen and covalent bonds
Some microbial control agent damage cellular proteins by breaking
replication and protein synthesis
microbial agents that interfere with DNA and RNA ?
1. breaking hydrogen and covalent bonds and
2. interfering with DNA and RNA replication and protein synthesis.
microbial control agents damage proteins and nucleic acids by ?
1. Heat, 2. filtration, 3. low temperature, 4. high pressure, 5. desiccation, 6. osmotic pressure, and 7. radiation
Name the 7 physical methods of microbial growth:
moist heat kills microbes by
Thermal death point TDP
lowest temp at which all microbes in liquid culture will be killed in 10 minutes?
Thermal death time TDT
length of time required to kill all bacteria in a liquid culture at a given temperature?
Decimal reduction time DRT
length of time inwhich 90% (a percentage) of a bacterial population will be killed at a given temperature?
100* celsius
Boiling at what degrees will kill many vegetative cells and viruses with in 10 min. ?
steaming under pressure is to
this is the most effective method of moist heat sterilization
In auto claving the steam must contact the material to be sterilized?
HTST pasteurization
in this process; A high temperature is used for a short time (72*C for 15s) to destroy pathogens with out altering flavor of food?
(UHT) treatments
In this process ultra high temp (140*C for 3s) is used to sterilize dairy products?
direct flame, incineration, hot air sterilization; kills by oxidation
what are the dry heat methods? and how does it kill?
equivalent treatments
Different methods of reduction of microbial growth that are called?