Sterilization and Disinfection

The process that destroys all forms of microbial life

Sterilization

Physical: Incineration, moist heat, dry heat, filtration, ionizing radiation

Chemical: ethylene oxide, vapor phase hydrogen peroxide

Two kinds of sterilization

Hazardous material is burned to ashes

Temperatures range from 870 C to 980 C

Safest method to ensure that no infective materials remain

Incineration (PS)

Autoclave

Steam, under 15 pounds per square inch of pressure causes denaturation of enzymes and structural proteins

Temperatures can range from 121-132 C for 30-60 minutes

Used for biohazardous trash and heat-stable objects

Moist Heat (PS)

Longer exposure times and a higher temperature than moist heat sources

Temperatures range from 160-180 C for 1.5-3 hours

Dry heat ovens

Dry Heat (PS)

Method of choice for antibiotic solutions, vaccines and other heat sensitive materials

Liquids can be pulled through a cellulose acetate or nitrate membrane with a vacuum

Air can be filtered through a HEPA filter

• - Can remove organisms larger than .3 micrometers

Filtration (PS)

Used for sterilizing disposables before use

Ionizing Radiation (PS)

Used in gaseous form for sterilizing heat-sensitive objects

Lengthy process and a health hazard

Ethylene Oxide (EtO) (CS)

Used to sterilize HEPA filters in biosafety cabinets and medical instruments

No toxic byproducts

Vapor-phase Hydrogen peroxide (CS)

The process of destroying pathogenic organisms, but not all microorganisms

Disinfection

Physical

Boiling, Pasteurizing, Nonionizing radiation

Chemical

Hypochlorite solutions, Ethyl or isopropyl alcohol, Hydrogen peroxide

Two types of disinfection

100 C for 15 minutes

Boiling (PD)

70 C for 30 minutes

Pasteurizing (PD)

UV lights are used in biosafety cabinets

Nonioinzing radiation (PD)

Household bleach

Most common disinfectant

1:10 dilution for tabletop cleaning and disinfecting

Hypochlorite solution

Used more as an antiseptic due to quick evaporation time

Ethyl or isopropyl alcohol

Used as a disinfectant on inanimate surfaces

Hydrogen peroxide

Used to disinfect tissue (skin) to prepare for an invasive procedure

70% ethyl alcohol followed by an iodophor coupled to a neutral polymer: Povidone-Iodine

Antiseptics