Research Flashcards
Can inhibit growth of many microorganisms by washing and scrubbing with soaps and detergents.
Microbial control
Process of removing or killing all microorganisms and viruses on or in a product.
Sterilization
Ensures complete destruction of all microorganisms, including cells, spores, and viruses.
Sterilization
Examples of sterilization
Dry heat ●Autoclaving ●Gas ●Various chemicals ●Certain types of radiation
Process that reduces number of potential disease-causing bacteria and viruses on a material until they no longer present a hazard
Disinfection
These terms mean the same as disinfection
Decontamination and sanitation
A chemical used to disinfect inanimate objects.
Disinfectant
●Method of disinfecting liquids.
Pasteurization
●Heat liquids to a certain temperature.
Pasteurization
●Does not totally destroy pathogens.
Pasteurization
Inactivation or removal of both microbial toxins and the living microbial pathogens.
Decontamination
Solutions used to disinfect skin and other living tissues.
Antiseptic
Reduction of microbial populations to levels considered safe by public health standards.
Sanitation
The suffix –cide or –cidal refers to
Killing
Examples of microbicidal agents
–Ex. Microbicidal agents (microbicides)
–Ex. Bactericidal agents
–Ex. Sporicidal agents
–Ex. Viricidal agents
Drug or chemical that inhibits the growth and reproduction of microorganisms.
Miscrobistatic agent
One that specifically inhibits the metabolism and reproduction of bacteria
Becteriostatic agents
Microbistatic technique examples
Lyophilization (freeze-drying) Rapid freezing (using liquid nitrogen)
Presence of pathogens in blood or tissues.
Sepsis
Absence of pathogens
Asepsis
Examples of asepsis
Hand washing; use of sterile gloves, masks, gowns; sterilization of surgical equipment; use of disinfectants.
Prevention of infection.
Antisepsis
Use of antiseptics.
Antiseptic techique
Who developed the antiseptic technique
Joseph Lister (1867).
Practice of excluding all microorganisms from a particular area, so that the area will be sterile.
Sterile technique
Methods used to destroy or inhibit microbial growth may be
Physical or chemical
Examples of Controlling Microbial Growth Using Physical Methods
Heat ●Combination of heat and pressure ●Desiccation ●Radiation ●Sonic disruption ●Filtration
Practical, efficient, and inexpensive method of sterilization
Heat
2 factors that influence effectiveness of heat for sterilization
temperature and time
●Lowest temperature that will kill all organisms in a standardized pure culture within a specified period.
Thermal Death Point (TDP)
●Length of time necessary to sterilize a pure culture at a specified temperature.
Thermal Death Time (TDT)
Heating materials in absence of moisture.
Dry heat
Dry heat must be baked
Must be baked at 160º to 165ºC for 2 hours or at 170º to 180ºC for 1 hour.
Other methods of dry heat
incineration
flaming surface of metal materials like forceps and loops.
Boiling or steaming.
Moist heat
Most pathogens are destroyed After
30 mins of boiling
not always effective against some endospores and viruses.
Boiling
Boiling not an option for
Thermophiles
Large metal pressure cooker that uses steam under pressure to completely destroy all microorganisms.
Autoclaving
Increased pressure raises the temperature of boiling water (i.e. above 100ºC) producing steam.
Autoclaving
Use of a pressure cooker.
Home canning
If foods canned without _____ some bacterial endospores may survive.
pressure
●For clothing, bedding, and dishes
●Use hot water with soap or detergent
●Agitate solution around items
Disinfecting technique
These disinfecting techniques kills most microbes.
Combination of heat, mechanical action, and chemical inhibition
●Metabolic activities slowed.
Cold
●Most microbes not killed, but growth inhibited.
Cold
not a good way to preserve bacteriological or biologic specimen.
Slow freezing
a good way to preserve bacteriological or biologic specimen.
Rapid freezing (liquid nitrogen)
Process of drying materials.
Many microbes can remain viable despite absence of nutrients and moisture.
Dried blood, fecal material, and dust may still contain viable microbes.
Desiccation
example of desiccation
Lyophilization (freeze-drying)
sometimes used to prevent or decrease microbial growth.
Ultraviolet (UV) light
Types of radiation that may be used to destroy or prevent microbial growth.
X-rays and gamma and beta rays
Often used to sterilize and clean delicate equipment.
Ultrasonic waves
●Consists of tanks filled with liquid solvent (usually water).
●________are passed through liquid.
●________dislodge organic debris.
●Materials must then be washed and sterilized by another method.
Ultrasonic waves
Short sound waves
Sound waves
●Filters of various pore sizes are used to filter or separate larger cells, larger viruses, bacteria, and other microbes from gases or liquids in which they are suspended.
● _______ used to prevent the outward and inward movement of microbes.
Filtration
Paper masks
Altering atmosphere of microbes to inhibit growth
Gaseous atmosphere
Chemical Agents Used to Inhibit Microbial Growth
●Temporarily or permanently.
●Different disinfectants have different properties.
●_______should be chosen based on their efficiency and effectiveness for a particular situation.
Disinfectants
How do disinfectants kill microorganisms
Some target and destroy cell membranes.
●Ex. Surface-active soaps and detergents; alcohols
●Some destroy enzymes and structural proteins.
●Ex. Formaldehyde and ethylene oxide
●Some attack cell walls or nucleic acids.
Can be used safely on human skin.
●Reduces # of organisms on the surface.
●Does not penetrate _________
Antiseptics
Pores or hair follicles
