microbiology ch7

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study outline key facts chapter 7

infections and food spoilage

control of microbial growth can prevent -------- and ------

sterilization

the process of removing or destroying all microbial life on an object

commercial sterilization

heat treatment of canned foods to destroy C. botulinum endospores

disinfection

process of reducing or inhibiting microbial growth on a non living surface (animated)

antisepsis

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?

sterilization

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

sanitation

microbial control: done by high temperature wash or dipping in chemical disinfectant: public health

sanitation

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.

sterilant

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

Biocides

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

acidic

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?

pasteurization

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?

permeability

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:

denaturing

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. ?

autoclav

steaming under pressure is to

autoclav

this is the most effective method of moist heat sterilization

directly

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?

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