Methods of Microbial control

Sterilization

kills everything including endospores.

Disinfection

killing organisms (vegetive cells)/ everything but endospores.

Decontamination

Lowering microbial levels to a safe level.

-cidal

to kill, e.g., bactericidal.

-static/stasis

not killing but inhibiting, e.g., bacteriostatic.

Incineration

Dry heat sterilization method. (sterilization)

Pasteurization

Moist heat treatment for decontamination of foods. (Decontamination)

Autoclave

Moist heat sterilization device using steam under pressure. 121c, 15psi (pounds per square inch) {for pressure rate} 15 minutes

Freezer burn

Damage caused by cold temperatures inhibiting and destroying bacteria. It can cause freezer burn from the ice crystals can poke bacterial pockets and destroy them.

Ionizing Radiation

High-energy radiation like gamma rays that can cause cellular damage. ex: gamma rays and x-rays.

Non-ionizing Radiation

Lower-energy radiation like UV rays that can form thymine dimers in DNA. Ex: UVrays. Uvc-265/UV cannot penetrate through layers.

Filtration

Method to remove microorganisms from liquids, gases, or heat-sensitive medications based on pore size.

Antiseptics

Chemical agents used on living tissues to reduce microbial counts, e.g., hydrogen peroxide, mouthwash.

Antibiotics

Natural compounds that kill or inhibit the growth of bacteria.

Antimicrobials

Made in a lab / synthetic or partially synthetic compounds that kill or inhibit microorganisms.

MHA Plate

Muller Hinton Agar: a lawn of bacteria covers the whole plate of bacteria to create a film.

Surfactants

Compounds in soap that reduce surface tension and friction. Wash for 30 seconds for clean hands.

Hand Sanitizers

At least 70% of alcohol to work. Alcohol dissolves lipids & dries them out.

Hot air

(sterilizations) 160c-2hr/170-1hr

boiling

100c - 30 mins (disinfection)

*moist/ steam can penetrate cells which is more effective

Which is more effective moist or dry heat?

cell death

unable to reproduce/gives up.

thyme-thymine dimers

(Longer we expose dimers, the harder for the cell to fix it)

used for bacteria

0.45nm (size of pore)

viruses

0.22nm (size of pore)

cold temps don’t kill, they just inhibit them.

cold temps don’t kill, they just inhibit them.