chapter 7 Flashcards
physical methods to control microorganisms (3)
– Low temperature storage
– Freezing
– Reducing available water
Freeze drying aka ___________ is widely used for what?
LYOPHILIZATION
preserve foods like coffee milk and meats
- __________ and __________ used in
processed meats have been shown to be a potent carcinogen - Numerous chemicals are
used as _____________
(Formaldehyde, phenols (animal tissues)
- nitrates and nitrites
- preservatives
- the suffix –cide means: to ____
- _________: chemical that destroys bacteria (not endospores)
- __________: a chemical that can kill fungal spores, hyphae, and yeasts
- _____________: a chemical that inactivates viruses
- _________: can destroy bacterial endospores
- _________ : and microbicide: chemical agents that kill microorganisms
- to kill
- bactericide
- fungicide
- virucide
- sporicide
- germicide
_________removing and destroying all microbial life
____________ eliminates MOST pathogens
___________ heat treatment to reduce organisms that cause food spoilage
_______________ process used to delay spoilage of perishable items
sterilization
disinfection
pasteurization
preservation
Autoclaving, incineration and membrane filtration are all examples of what type of microbial control?
sterilization
- the suffix –static means: to _____ _____
- ___________: prevent the growth of bacteria
- _________: inhibit fungal growth
- _____________: materials used to control the growth of microorganisms
- stand still
- bacteriostatic
- fungistatic
- microbiostatic
Regulated by–FDA
1. ____________ (living/animate surfaces)
EPA
2. _______________ (non-living/inanimate surfaces)
- antiseptics
- disinfectants
disinfectants and antiseptics are examples of what type of microbial control?
disinfection
What is microbial death?
cell structures become dysfunctional and entire cell sustains irreversible damage
germicidal agents cannot destroy ___________ while sterilants destroy all ____________
- endospores
- microorganisms
In microbial death a cell can no longer do what?
reproduce/grow
When does microbial death begin?
when a certain threshold of microbicidal agent is met.
– Daily life
– Hospital
– Microbiology laboratories
– Food and food production facilities
– Water treatment
All of these factors can affect what?
Microbial control Methods
T/F Selection of an effective antimicrobial procedure has drawbacks and procedural parameters
TRUE
Effectiveness of treatment to kill microbes depends on what 4 things?
- # of microbes
- Environment (organic matter, temperature, biofilms)
- Time of exposure
- Microbial characteristics (endospores, cell wall)
name 4 PHYSICAL methods of microbial control?
Chemical methods use a variety of what?
- Heat
- Irradiation
- Filtration
- Mechanical removal
antimicrobial chemicals
What is the critical consideration for the type of microbe?
- resistant or susceptible to methods
What are the 5 resistant microbes?
- Bacterial endospores
- Protozoan cysts and oocysts
- Mycobacterium
species - Pseudomonas species
- Naked viruses
what scientific term is being described below:
_______________
– Pasteur developed to avoid spoilage of wine
– Does not sterilize but significantly reduces organisms
– Used to increase shelf life of food
– Most protocols employ HTST method (High Temp Short Time)
pasteurization
What resistant microbe is resistant to heat, drying, and numerous chemicals?
Bacterial endospores
Protozoan cysts and oocysts are generally excreted in what?
- what does it cause?
excreted in feces and cause diarrheal disease
- _________ method (High Temp Short Time)
* Heated to ___ °C and held for 15 seconds - Other protocol _____ (Ultra High Temperature)
* Heated to ____°C -150°C, held for several seconds then rapidly cooled
- HTSA method
heated to 72 °C - UHT Method
heated to 140°C -150°C
What resistant microbe has mycolic acid in their cell wall structure and initiates resistance?
Mycobacterium species
Where do Pseudomonas
species grow?
in presence of many chemical disinfectants
What do naked viruses lack and what are they more resistant to?
Lack envelope and are more resistant to chemical
killing
Autoclave is _____________ steam and achieves sterilization at what temp, pressure and time?
Autoclave is effective against vegetative cells and endospores but not ______
Prions are destroyed under what conditions?
pressurized steam
121°C and 15psi in 15 min
prions
Prions destroyed at 132°C and 15psi for 4.5 hours
which heat is more effective between dry heat and moist heat.
Moist heat is more effective because of the steam
T/F Hot air sterilization is more effective than moist heat?
FALSE, Not as effective as moist heat & Sterilization requires longer times and higher temperatures
What type of radiation is described below?
the radiation ejects orbital electrons from an atom causing ions to form
Ionizing radiation
What type of radiation is described below?
excites atoms by raising
them to a higher energy
state but does not ionize
them
– UV: modifications and
breaks in DNA
Nonionizing radiation
How do dry heat control conditions differ from autoclave control conditions? (temp/time)
- 200°C for 1.5 hours (dry heat)
vs. - 121°C for 15 minutes (autoclave)
- T OR F: A-T bonds are harder to break than C-G bonds because A-T has 3 strands to bind while C-G only has 2
- Non-Ionizing Radiation
(ultraviolet, 260 nm) damages DNA by creating what?
- FALSE, A-T bonds are easier to break than C-G bonds because A-T only has 2 strands to bind while C-G has 3
- thymine dimers
- Solutions of 60% -80% isopropyl or ethyl alcohol kill vegetative bacteria and fungi but are not effective against what?
- Mode of action: coagulation of __________ and essential ___________
– damage to lipid membranes - Alcohol is commonly used as what?
- endospores and some naked viruses
- coagulation of proteins and essential enzymes
- antiseptic and disinfectant
- Biguanides
-phenolics
-quats
There 3 chemicals are used as controls to disinfect and sterilize what structure?
cytoplasmic membrane
- Alcohols
- Aldehydes
- Halogens
- Metals
- Ozone
- Peroxygens
-Phenolics
There chemicals are used as controls to disinfect and sterilize what?
proteins
- The effectiveness of Hydrogen peroxide depends on what?
- Living tissue produces what that breaks down hydrogen peroxide to oxygen and water?
- 2 reasons hydrogen peroxide is useful as disinfectant?
- surface being treated
- catalase enzyme
3.* Leaves no residue
* Doesn’t damage most materials
What 2 chemicals are used as controls for DNA?
- ethylene oxide
-aldehydes
________________ is a type of halogen that destroys all types of organisms and viruses (including spores)
_____________ is a type of halogen that is not reliable with endospores and is used in tincture or iodophore on skin
chlorine
iodine
Heavy metal compounds combine with…?
enzymes and proteins
- Mode of action for phenol (carbolic acid) (2)
- what does phenol kill?
- Is phenol reliable?
- what 2 phenols are used in soaps and lotions?
- Destroy plasma membrane
* Denature proteins
- Destroy plasma membrane
- most vegetative cells
* Can kill mycobacterium at high concentrations. - No, not on all groups of viruses
- Triclosan and hexachlorophene phenols
Creams containing silver
sulfadiazine are used for what?
What are they available on?
prevent secondary infections
bandages for wound care
