• Least: fungi, bacteria, enveloped viruses, protozoans, and "animals"
• Middle: cysts, zygospores, non-enveloped viruses, hardy vegetative bacteria (thick walls)
• Most: endospores and prions

• removal of all viable organisms
• may be physical or chemical
• chemical agents/sterilants end in "-cide"

• prevent growth ("control") germs without necessarily destroying them
• mainly chemical agents
• strict microbistatics end in "-static"

• reducing microbial load through displacement
• detergents and soaps are most common form
• sometimes sanitization is rigorous enough to be called sterilization; other times not

• reducing microbial load on te skin or other iving tissue by removing oils, debris, etc.
• degerminants target debris, not bacteria. 

• a broad-specturm chemical agent that kills many "Germs" but may not kill all resistant cells nor obliterate all spores.
• used on both living and nonliving things
• not a sterilant

• a broad spectrum physical or chemcial agent that destroys resistant cells but not all spores
• used only on nonliving things

• the prevention of infection through physical or chemical means
• "antiseptics" are chemicals that can have microbicidal or microbistatic effects

1. Disrupt cell walls - (alcohol and penicillin)
2. Disrupt cell membranes - (surfactants/detergents)
3. Disrupt protein/nucleic acid synthesis - (radiation, formaldehyde, ethylene dioxide, chloramphenicol)
4. Disrupt protein function - (moist heat, organic solvents, phenolics)

Thermal Death Point

lowest temperature required to kill all microbes of interest in a 10 minute time span

• sterilization
• as pressure increase boiling temp of water increases and temp of steam produced increases
• 15 psi= 121 degrees C steam
• best for durable, hardy objects and items that will be discarded

• circulates pressurized steam around what you want to sterilize.
• used in health care and industry

• Sterilization
• intermittent sterilization/tyndallization
• good for culture media or foods
• gets rid of spores on delicate items
• coax endospores into becoming a vegetative cell then you kill it

• Heating to a specific temperature for a specific period of time without allowing recontamination
• liquid or solid foods
• disinfection
• is not homogenization

• Disinfection procedure
• pros: quick and easy, good for most microbes
• Cons: items typically easily recontaminated

• Sterilization
• Forms
• Incineration: bunsen burner, chamber incinerators
• Hot air (oven)
• Pros: versatile, different ways of doing it, can be used on many different products
• Con: Time-consuming

• drying out (dehydration) at ambient temperatures
• redues moisture availability
• hurts some, preserves others
• ways: sun, mechanical devices

• combination of cold and dessication
• used to preserve cells, microorganisms, or proteins for scientific purposes
• freeze and dehydrate at the same time

• energy emitted from atomic activities and dispersed at high velocity through matter or space
• Two types: Ionizing and non-ionizing
• Nuclear radiation

• Sterilization
• ex) gamma rays (most effective) x-rays (middle) cathode rays (least effective)
• good for items that cant be treated by heat or chemicals:
• food and medical products ( devices, drugs, vaccines)
• When radiation causes electrons to fly off of the atom

• Disinfection
• ex) UV radiation
• great for large-scale applications
• disinfecting surgical rooms, treating drinking water
• requires direct contact with target surface (doesn't penetrate)
• when radiation excites the atom to a higher energy state but doesnt destroy it from the atom. 

• options: plastics, earth materials
• liquid filtration
• filters have different pore sizes
• vacuum suction
• air filtration
• HEPA filters - very small pore size