Physical/Chemical Controls Flashcards
4 modes of action (broad)
Damage to cell wall
Disrupt CM
Inhibit synthesis of proteins/nucleic acids
Alter fx of proteins/nucleic acid
Cold temp #s?
Refrigeration just slows metabolism
Freezing (-70C) stops metabolism but doesn’t kill
Heat MOA
Disrupt CM, denature proteins/inactivate nucleic acids
Fluidity proportional to heat (loss of selective permeability)
Proteins’ Hbonds break — causing an unfolding and separation of DNA
Dry heat (#s)
2 hours @ 160-180C
Not good for liquids or organic compounds that we don’t want to denature
Steam heat (#s)
15 mins @ 15 lbs @ 121C
Kills spores (maybe need > 15 mins for deeper penetration)
Incineration
KILLS EVERYTHING
1800F
Gamma radiation
Alters proteins; bulk/broad sterilization (deep penetration)
Ionizing radiation (electron beam radiation)
Alters nucleic acid (direct exposure)
Decontaminate packages (UPS) and industrial uses
Non-ionizing radiation (UV)
Nucleic acid mutations
Wavelength (240-280, 254nm)
10 seconds-30 minutes of DIRECT contact
Decon of air/other gases
Membrane micropore filers
.22 micron pore size (effective on typical bacteria)
Moderate efficacy on mycoplasma. Chlamydia, and bacteria
HEPA filters
Adherence of particles (rather than direct filtering through a pore)
Effective at containing particles .3 um and larger (good at bacteria, ok at viruses)
Microbicidal/Sporocidal (slowly)
Maybe be sterilants under proper conditions
High level disinfectant
Most common
Variable efficacy (maybe against fungi, viruses, few are sporocidal)
Intermediate
Glutaraldehyde (2-5)
High level
Sterilants
Structural proteins/enzyme disruption
Vegetative bacteria dead w/in minutes
3-10 hours for spores
H2O2 vaporized 25%
High level
Sterilant
Free radical formation
6 hours
