Microbial Control: Physical Methods

28 terms by kiatamaki 

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Moist Heat: Method(s)

Boiling; Autoclaving (pressure-cooking, steam heat); Pasteurization (batch method, flash, and ultrahigh-temperature pasteurization); Ultrahigh-temperature sterilization (flash-heating via super-heated steam)

Moist Heat: Actions

denatures proteins and destroys cytoplasmic membranes

Moist Heat: General Uses

disinfect, sanitize, sterilize, and pasteurize; more effective than dry heat b/c water is a more efficient conductor of heat than air

Moist Heat: Representative Uses
BOILING

- disinfection of baby bottles - sanitization of restaurant cookware and tableware

Moist Heat: Representative Uses
AUTOCLAVING

sterilization of medical and laboratory supplies that can tolerate heat and moisture - sterilization of canned food

Moist Heat: Representative Uses
PASTEURIZATION

destruction of all pathogens and most spoilage microbes in dairy products, fruit juices, beer, and wine

Moist Heat: Representative Uses
ULTRAHIGH-TEMP STERILIZATION

sterilization of dairy products, e.g., dairy creamer served in restaurants

Dry Heat: Method(s)

Hot Air; Incineration

Dry Heat: Actions

denatures proteins, destroys membranes, oxidizes metabolic and structural chemicals

Dry Heat: General Uses

useful for material that can not be sterilized or are damaged by moist heat; less effective than moist heat, requires higher temperatures for a longer time

Dry Heat: Representative Uses
HOT AIR

sterilization of materials that cannot be exposed to moist heat, e.g., oils, powders, glassware, metal objects

Dry Heat: Representative Uses
INCINERATION

ultimate means of sterilization, oxidizes everything completely; used for inoculating loops, flammable contaminated medical waste, diseased carcasses

Extreme Cold: Method(s)

Refrigeration; Freezing (slow and flash)

Extreme Cold: Actions

inhibits microbial metabolism, growth and reproduction in most pathogens, predominantly mesophiles (but can induce growth in psychrophiles)

Extreme Cold: Representative Uses

food preservation

Drying: Method(s)

Desiccation; Lyophilization ("freeze-drying")

Drying: Actions

inhibits microbial metabolism, growth and reproduction in most pathogens due to removal of water

Drying: Representative Uses

food preservation

Filtration: Method(s)

use of a filter to trap particles (cells or viruses) and separate them from the fluid (liquid or gas); use of vacuum common

Filtration: Actions

physically separates microbes from air and liquids

Filtration: Representative Uses

sterilization of air and heat-materials solutions such as ophthalmic and enzymatic solutions, vaccines, and antibiotics; filtration of airborne contaminants through HEPA filter

Osmotic Pressure: Method(s)

exposure to hypertonic solutions (high concentrations of salt or sugar) to induce cell desiccation

Osmotic Pressure: Actions

inhibits microbial metabolism, growth and reproduction due to removal of water

Osmotic Pressure: General Uses

food preservation, esp. jams, jellies, honey, jerky, salted fish, pickles; fungi are more resistant to hypertonic environments due to "osmotolerance"

Radiation: Method(s)

Ionizing radiation (electron beams, gamma rays, X-rays); Non-ionizing radiation (UV light)

Radiation: Actions

disruption of hydrogen bonding, oxidizing double covalent bonds, creatin highly reactive ions which denature other molecules, esp. DNA (ionizing); formation of Pyrimidine Dimers inhibits DNA transcription and replication (non-ionizing); causing fatal mutations and cell death

Radiation: Representative Uses
IONIZING RADIATION

sterilization of medical and laboratory equipment; food preservation (food irradiation)

Radiation: Representative Uses
NON-IONIZING RADIATION

disinfection and sterilization of surfaces and of transparent fluids, air and gases

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