Chapter 7 Flashcards
_______: removing and destroying all microbial life
Sterilization
____ _______: Killing Clostridium botulinum endospores from canned goods
Commercial sterilization
_______: destroying harmful microorganisms
Disinfection
______: destroying harmful microorganisms from living tissue (antiseptic)
Antisepsis
What is degerming?
The mechanical removal of microbes from a limited area
What is sanitization?
lowering microbial counts on eating utensils to safe levels
Biocide (germicide) is what?
Treatments that kill microbes
Name two germicides
Fungicide and virucide
What does Virucide do?
Inactivates viruses
What does bacteriostasis do?
Inhibits growth and multiplication of microbes
What is a problem with bacteriostasis?
Once a bacteriostatic agent is removed, growth might resume
What are the three main ways various agents kill or inhibit microbes?
Alteration of membrane permeability, damage to proteins, and damage to nucleic acids
One way agents kill or inhibit microbes is through altering the membrane permeability. What does this cause?
Lysis or death
One way agents kill or inhibit microbes is by damaging the proteins. How does this happen?
Proteins are denatured by heat and chemicals.
One way agents kill or inhibit microbes is by damaging the nucleic acids. How does this work?
Damage is caused by heat, chemicals, and UV. Microbes then cannot replicate or make protein
Bacteria usually die at a ______ rate
constant
Which four factors affect the death rate of microbes?
- Number of microbes
- Environmental influences
- Time of exposure
- Characteristics of microbe
The more microbes present, the longer it takes to kill them. True or False
True
What are the four environmental factors that affect the death rate?
- Presence of organic matter
- Biofilms
- Nature of suspending medium (heat tx)
- Temperature
Chemical antimicrobials require what?
Extended time (affects death rate)
What are the main four environmental factors that affect the growth of microorganisms
- Heat
- Filtration
- Radiation
- osmotic pressure
Thermal death point?
lowest temperature at which all microbes in a particular liquid suspension will be killed in 10 minutes
Thermal death time?
Minimal length of time for all microbes in a liquid culture to be killed in a given temperature
Decimal reduction time