Week 14- controlling microbial growth Flashcards
Describe the following terms as they relate to controlling microbial growth in the environment:
pasteurization
use of heat to remove of pathogenic microorganisms in liquids
Describe the following terms as they relate to controlling microbial growth in the environment:
degerming
physical removal of microorganisms
Describe the following terms as they relate to controlling microbial growth in the environment:
sterilization
Should remove all microorganisms
like spores, endospores, cysts
Describe the following terms as they relate to controlling microbial growth in the environment:
aseptic
an environment that is completely free of microorganisms
Describe the following terms as they relate to controlling microbial growth in the environment:
antisepsis
remove all pathogenic microorganisms on human tissue
like e.coli
Describe the following terms as they relate to controlling microbial growth in the environment:
disinfection
Remove all pathogenic microorganisms on objects
like ecoli
Describe the following terms as they relate to controlling microbial growth in the environment:
sanitation
disinfectant at public health standard
What is the difference between an agent that is “cidal” versus “static” (i.e. bactericidal versus
bacteriostatic agent or fungicidal versus fungistatic
Static- will slow down mo
cidal- will kill mo
Define microbial death.
A microorganisms inability to reproduce under ideal conditions
What are the two general methods of controlling microbial growth?
Physical- heat, refrigeration/freezing, desiccation, osmotic pressure, radiation
chemical-
What specific structures/components of microbes do the modes of action of antimicrobial agents
affect?
How does the damage to each of these structures (from question above) affect the microbe adversely?
Cell wall-cells burst
cell membrane-contents leak out
viral envelope-disable attachment and prevent replication
protein-denature proteins-cause death
nucleic acids-halt protein synthesis through action on rna
Describe the main factors that need to be considered when choosing an antimicrobial agent/method and
how they affect the efficacy of an agent/method
Site
organic materials-ex-feces vomit and tissue
typically remove organic material before using antimicrobial agent
How can you adjust time to affect the effectiveness of antimicrobial methods/agents
some agents take longer times to be more effective
time needed to sterilize volume of liquid
(like 30 sec vs 5 min for a spray)
Which types of microbes are more susceptible to antimicrobial agents
enveloped virus
gram positive/gram negative
Which types of microbes are more resistant to antimicrobial agents
Bacteria endospores
cysts
protozoa
Tuberculosis
High level germicide
used on mo that are hard to kill
resistant
intermediate level germicide
used on some mo that are intermediate to kill
low level germicide
Used on Mo that are easy to kill
susceptible
How does high heat affect microbes?
denatures proteins
disrupts with structure and function of nucleic acids
What is moist heat used for and give several examples.
Used to disinfect, sanitize, sterilize, and pasteurize
Denatures proteins and destroys cytoplasmic membran
more affective then dry heat
Boiling, Autoclaving, Pasteurization, Ultrahigh-temperature sterilization
How are time and heat related when determining effectiveness of a heat method?
Typically with increased heat—time using the method can decrease
time needed to sterilize at a set temperature
When would you use dry heat?
powders or incineration of biological tissue
How do refrigeration and freezing harm microbes?
will slow down metabolism
ice crystal could form in freezing and kill
How does filtration work? What is it used for?
will filter mo because of pores-
like liquids that are heat sensitive and air quality
pores size will determine what size of mo can filter through
