U1 LAB: CONTROL OF MICROBIAL GROWTH Flashcards
Factors affecting Microbial Growth
- Type of Organism
- Microbial load
- Concentration of agent
- Presence of organic material
- Nature of surface (to be disinfected)
- Contact time
- Temperature
- pH
- Compatibility of disinfectants
This is the causative agent of Mad Cow Disease/CJD and is made up of proteins.
Prions (most resistant, need to burn for it to be killed)
This refers to the absence of microbes in an area or object.
Asepsis
This refers to the methods employed to prevent entry of organisms to body, or equipment used for microbial cultivation.
Aseptic Technique
This involves chemical disinfection of living tissues, as well as in treatment of wounds.
Antisepsis
Chemical agent used in antisepsis
Antiseptic
This is a condition in which microbial growth and multiplication is halted or inhibited.
Bacteriostasis
Bacteriostatic methods include?
refrigeration, dyes
These are chemical sterilants used to destroy all forms of life.
Biocide
Other term for biocide
Chemical sterilants
These are inadvertently introduced to specimens or culture.
Contaminant
This is the process of removal of pathogenic microorganisms so materials are safe to handle/dispose.
Decontamination
This refers to the removal of transient microorganisms from the skin.
Degerming
This is the process of destruction of pathogenic microorganisms except spores, prions, and others.
Disinfection
Degerming methods include?
mechanical cleansing, use of antiseptics
This refers to the reduction of pathogens on eating utensils to safe public health levels.
Sanitization
Sanitization methods include?
mechanical cleansing, use of chemicals
This is the destruction of all forms of life including bacterial spores.
Sterilization
This is the lowest temperature in which all bacteria in culture will be killed in 10 minutes.
Thermal Death Point
This is the minimal length of time in which all bacteria in liquid suspension will be killed at a given temperature.
Thermal Death Time
Methods of control
Physical Means and Chemical Means
Physical Means require the use of?
heat
Chemical Means require the use of?
alcohol
This is the most commonly used physical method.
Heat
2 types of heat
Moist Heat, Dry Heat
Principle of Dry Heat
Oxidation
Examples of Dry Heat
Oven (for glasswares, 3 hours)
Dry Heat
longer exposure time, ___ temperatures
higher
This is used to sterilize glasswares.
Hot Air Oven
Temp requirements for dry heat
160-180C for 1.5-3 hours
Examples for open flame
Bunsen burner, Alcohol lamp
This is used for the sterilization of inoculating loops, needles, mouth of tubes.
Open Flame/Flame sterilization
This is the only way to destroy prions, and is used for disposal of hospital infectious waste.
Incineration (Incinerator)
Incineration is outlawed by?
RA 8749 (Clean Air Act of 1999)
Other term for Moist Heat
Heat under Steam Pressure
Principle of moist heat
Coagulation of Proteins
T/F: Dry heat is more effective than moist heat
False
Moist Heat
_____ time of exposure
shorter
Moist heat is the sterilization method choice for?
heat stable objects
Temp requirements for Autoclaving
121C, 15psi (1 atm) for 15 minutes
This kills all microorganisms except prions.
Autoclave
T/F: In opening the autoclave, you must let it cool down first to decrease pressure inside.
True
This is a form of disinfection under heat that doesnβt kill spores.
Boiling
Temp requirements for boiling
100C for 10-15 minutes
This eliminates food borne pathogens responsible for food spoilage.
Pasteurization
Methods under Pasteurization
- Batch Method
- Flash Method
- High tempt short time
Batch Method
63C for 30 minutes
Flash Method
72C for 15 seconds
High Tempt Short Time
72C-140C then 72C for <5sec
This refers to a flowing steam, is fractional and intermittent.
Tyndallization
Tempt requirements for Tyndallization
100C for 30 mins for 30 days
1st day of Tyndallization
kills vegetative states of bacteria
2nd day of Tyndallization
endospores enter vegetative state
3rd day of Tyndallization
kills endospores in vegetative state
This is used for sterilization of high protein media.
Inspissation
Tempt requirements for inspissation
75-80C for 2 hours on 3 consecutive days