Control Of Growth Flashcards
Disinfect
Reduce number of pathogens to safe level on inanimate objects
Example cleaning a lab bench
antisepsis
Disinfect on living things,
Reduce number of pathogens to safe level on living things
Microbiocidal
Kill micro organisms
Bactericidal
Kills bacteria
Viricidal
Kills viruses
Fungicidal
Kills fungi
Tuberculocidal
Kills TUberuculosis
Microbiostatic
Inhibits growth,
If agent removed, growth continues
Example: refrigerator
Bacteriastatic
Inhibits growth of bacteria
Degerming
Mechanical removal of MO
Reduce number by brushing, flossing, hand washing, scrubbing
Pasteurization
Heat used to reduce spoilage MO
And kill disease causing pathogens
Decontaminate
To reduce number of MO to safe level
Sanitize
Similar to disinfect used in food industry
Mysophobia
Cypriphobia
Mysophobia: fear of germs
Cypriphobia: fear of getting an STD
Factors that effect growth
- Concentration of disinfectant
- Time to work
- Environmental conditions ( temp and PH)
- Site/tissue to be treated
- Sensitivity of MO
- Microbe density
- Real world considerations ( cost, smell, stain ect.)
How do control agents work?
- Affect cell membrane or cell wall
- Affect DNA by mutation
- Affect protiens
Sterilize
Kill all MO
All of them including viruses and endospores
Moist heat
Used to disinfect, sanitize, sterilize, pasteurize
Kills by denaturing proteins
Penetrates and water conducts heat better,
Boiling: kills but not sterilized( virus and endospores survive)
Autoclave: sterilized at 121 C and 15 psi for 15 min
(Tape is often used to insure conditions are met)
Kills endospores but not prions)
Effective on equipment that can withstand conditions
Pasteurization
“Sanitize milk”
Reduce spoilage MO and kill pathogens
It is a time and temp relationship
Not sterilized (other countries do this but changes taste)
Dry heat
Killing cells
Examples:direct flame (lab)
Incineration for prions and burn boxes(a very high temp)
Low heat (cooling)
Decrease growth by slowing protiens down
Refrigeration : some MO grow ( listeria, Yersinia, psycotrphes)
Freezing: does not kill MOs (Bactericidal)
Slow cooling more effective than fast
Radiation
UV: used to sterilize surfaces but can NOT penetrate
Mutates DNA
Ionizing radiation: high energy radiation
Causes free radical in cells that kill them
Used on medical equipment and on food (bread and hamburger)
Filtration
Air filtration
Small pores trap MO
Is not sterilized
HEAP filters ( some prokaryotes and virus get through)
Rooms pressurized to keep “cleaner air in”
Membrain
Think cleaning water
Used for filtering vaccines
Desiccation
Means to dry out
Think jerky or dried fruit
Important in history for survival
Sound waves
Cavitation uses high frequency to creat bubbles that kill cells
Clear debris off medical equipment
Most effective on gram -
Is not sterilized or disinfected
Osmotic strength
Put lots of salt or sugar in food to preserve it
Causes cells to dry out
Cultured materials
Beer, wine, yogurt
Alcohols
Disrupts cell membrane of all living things
Advantage-cheap and easy
Disadvantage- evaporate, does not kill endospores,
Used to degerm skin (must be in correct concentration)
Aldehydes
Affects proteins and nuclaic acid
Advantages: sporicidal and can sterilize
Disadvantage: toxic, carcinogen
Used: add as vaccine preservative, soak heat sensitive instriments
Gases ( ethylene oxide)
Works on proteins
Advantage: penetrate, effective, sterilize
Disadvantage: carcinogen, explosive, highly regulated
Used to sterilize medical devices and our petri plates
Halogens
Chlorine and iodine
Broad range and cheap, and fast
Disadvantage: reacts with organic compounds
Used: pools and for clean water
Metals (silver)
Works by denaturing protein
Advantage: effective
Disadvantage: toxic, persist, expensive
silver for wound cleaning or eye drops
Mercury( treating material and syphilis)
Copper for algae
Peroxide
Hydrogen peroxide and ozone
Advantage: fast, used on non living things, no residue
Disadvantage: can damage tissue
Uses: teach whiting, pools in Europe, surface cleaner
Phenolic compounds (tea tree oil, pinesol)
Destroy PM and protiens
Advantage: first known disinfect, effective, cheep, works if organic material present
Disadvantage: smell, irritating, not great against viruses
Uses: cleaning, soap
Quats ( surfactants)
Works by affecting plasma membrain
Advantage: cheap and effective
Disadvantage: takes time, endospores, mycobacterium non enveloped not effected
Uses:
Lab bench cleaner
Good on inanimate objects
Biological control
Fermentation
Cultures like yogurt
Phage use ( antibiotic resistance)
