Module 8 - Notes Flashcards
What are the 3 main methods of microbial control?
Physical
Mechanical Removal
Chemical
What are the 2 categories of physical microbial control?
Heat
Radiation
What are the 2 categories of Heat to control microbial infection?
Dry Heat - Like oven
Moist Heat - Like Boiling of autoclave
What types of microbial controls do you use on inanimate items (non-living)
Sterilization
Disinfection
Sanitization
What types of microbial controls do you use on living tissues?
Antiseptics
Degerming
What is sterilization?
Completely eliminate all vegetative cells, endospores and viruses
Eliminates all microbial risk
Only used on inanimate items.
What is Disinfection?
Reduces or destroys microbial load using heat or chemicals.
(there can still be some bacterial life)
Only used on inanimate items
What is Sanitization?
Reduces microbial loads to a safe public health level using heat or chemicals
Only used on inanimate items
What is Antisepsis?
Reduces microbial load using antimicrobial chemicals on living tissues
What is degerming?
Reduces microbial load using scrubbing and mild chemicals on living tissues.
You have injured your arm and your sibling tells you that you must sterilize your would. Why are they wrong?
A) Sterilization is a process that uses scrubbing and you could damage the wound
B) Sterilization is a process exclusively used on inanimate objects
C) Sterilization will only reduce the microbial load without killing the pathogen.
D) Sterilization absolutely requires heat to completely destroy the microbes.
B) Sterilization is a process exclusively used on inanimate objects
What are the 2 categories of radiation for the physical methods of microbial control?
Nonionizing - UV
Ionizing - Xray
Dry heat methods for microbial control include a dry oven and incineration (flame). What level of microbial control is achieved with either method?
Sterilization
Moist heat methods for microbial control include autoclave (steam & pressure) and boiling water or pasteurization. What level of control is achieved with autoclaves?
Sterilization
but only if held at 121 degrees Celcius for 15 minutes or more.
15 minutes is how long it takes to kill spores
Moist heat methods for microbial control include autoclave (steam & pressure) and boiling water or pasteurization. What level of control is achieved with boiling water of pasteurization?
Disinfection
Reduces bacterial loads but only eliminates heat-sensitive pathogens.
Not sterile
What is HTST Pasteurization of milk?
High temp short time
milk is heated to 72 degrees celsius for 15 seconds then bottled and refrigerated.
Shorter shelf life
What is UHT pasteurization for milk?
Ultra High Temperature
Milk is heated to 138 degrees celsius or more for 2 or more seconds, then sealed in airtight containers for up to 90 days without refrigeration. (tetra pack milk)
What other physical methods of microbial control can be used besides heat or pressure?
Cold - Refrigeration or freezing
Dessication - Drying
Both methods just control growth. They do not reduce the population by killing.
For a research project, you pasteurized your growth medium. Once the process is complete, you leave your flask on the bench to cool down. After a few days, you notice growth in your medium, what is the best explanation?
The aim of pasteurization is to reduce the microbial population to a safe level; therefore you do not sanitize your growth medium.
What is an example of a mechanical process to control microbial growth?
Filtration.
Effectiveness depends on pore size
HEPA filters have a 0.3 micron pore size. (used to remove microbes from air)
Membrane filters have a 0.2 micron pore size or smaller. (Used in liquid solutions)
What are the 2 categories of chemical microbial control?
Gases
Liquids
Gases used in chemical methods of microbial control can achieve what level of control?
sterilization or disenfection
What are the examples of liquid chemical controls used on living tissues?
Chemotherapy (taken internally)
- Antibiotics
- antivirals
- Antiparasitic
- Antifungal
Antisepsis (Applied topically)
What are the 3 main categories of antimicrobial agents?
Static (stops growth)
Cidal (kills)
Lytic (Lyses)
examples
bacteriostatic/cidal/lytic -targets bacteria
fungistatic/cidal - targets fungi
viricistatic/dal - targets viruses
sporocidal - targets spores