Physical and Chemical Control of Microbes
Which of the following are some of the desirable qualities in a germicide?
-Broad-spectrum action -Selective toxicity -Penetrating ability -Rapid action -Solubility in a solvent
Phenolics typically kill microbes by
-Denaturing metabolic enzymes -Disrupting the cell membrane -Disrupting the cell wall
Alcohols are commonly used for:
-Disinfection of medical equipment -Degermination of skin
Which items can be sanitized by boiling with boiling water prior to safe, acceptable use?
-Drinking water -Utensils -Bedding and clothing
Iodine compounds are commonly used for:
-Emergency disinfection of drinking water -Antisepsis of skin -Treatment of skin wounds -Disinfection of medical equipment
Which of the following compounds are commonly used as gaseous sterilants or disinfectants?
-Ethylene oxide -Propylene oxide -Chlorine dioxide
Which of the following are examples of chemical agents used to control microbes?
-Heavy metals -Phenolics -Aldehydes -Halogens -Oxidizers -Alcohols
What are the effects of adding pressure to water in an autoclave?
-Increases boiling point of water -Increases temperature of steam
Which of the following statements are correct regarding OPA?
-OPA is an aldehyde -OPA is non-irritating to eyes and nasal passages
The four general cellular targets of antimicrobial agents are
-Protein function -The cell membrane -The cell wall -Nucleic acid synthesis
Alcohols are effective against
-Resistant bacteria -Enveloped viruses
Which are goals of pasteurization?
-Retention of liquid qualities -Reduction of microbial load
Which of the following statements about soaps are correct?
-Soaps help to mechanically remove surface debris -Some bacteria can grow on soap as a nutrient source. -Soaps are only weakly microbicidal.
As the most extensively used chlorine compounds, hypochlorites are used for
-Swimming pool treatments -Wound treatment and skin cleasing -Household cleaning -Food equipment sanitation
What factors must be considered in order to adequately sterilize using heat?
-Temperature -Length of exposure -Presence of water
Which root indicates the ability to kill microorganisms?
-cide
A critical concern for the food packaging industry is the elimination of endospores of
Clostridium botulinum
Classification of medical device
Critical- syringe needle Semicritical- dental mirror Noncritical- blood pressure cuff
chlorine dioxide typically kills microbes by:
Disrupting protein function
The dosage of radiation is measured in _________________.
Grays
Which four of the following are examples of physical agents or mechanical means used to control microbes?
Heat, cold, radiation and filtration
Which two types of macromolecules make up the majority of the cell membrane in organisms?
Lipids and Proteins
Disinfection destroys
Only vegetative bacterial cells
________________ is a technique in which heat is applied to liquids to kill potential agents of infection and spoilage.
Pasteurization
Which levels of protein structure are disrupted in denaturation?
Secondary and Tertiary
Which of the following heavy metals are still in used in germicidal preparations?
Silver and Mercury
Dyes are important for:
Staining techniques, selective and differential media, chemotherapeutic drugs
Why do younger, active cells die more quickly when exposed to microbicidal agents.
They are more metabolically active
_____________ are chemical agents applied directly to body surfaces to inhibit vegetative pathogens.
antiseptics
Any process or agent that inhibits bacterial growth is referred to as _____.
bacteriostatic
A _____________ agent will inhibit the growth of bacteria, whereas a ____________ agent will kill bacteria.
bacteriostatic; bactericidal
If an agent disrupts the cell wall, the cell is likely to experience:
death by lysis
The disruption of proteins from their native state is known as ____________.
denaturation
UV radiation is usually used for ___________.
disinfection
__________ heat requires longer exposure times and higher temperatures than _________ heat.
dry; moist
______________ oxide is valuable for sterilization of heat-sensitive objects such as plastics, surgical and diagnostic appliances, spice, but other related gases are available that are less toxic.
ethylene
True or False: Only a few microorganisms are killed by Iodine even if proper concentrations and exposure times are used.
false
True or False: There are several degrees of sterility, based on the destruction of endospores.
false
True or false: Biological matter such as serum, blood, or urine increases the effectiveness of a germicide.
false
True or false: Ionizing radiation is not an effective method of controlling microbes in food products.
false
True or false: The effectiveness of an antimicrobial agent is only governed by the time of exposure to the agent.
false
True or false: The shortest length of time required to kill all test microbes at a specified temperature is referred to as the thermal death point.
false
True or false: Thymine, uracil, and cytosine are called purines which are a type of nitrogenous bases found in either DNA or RNA.
false (they are pyrimidines)
True of false: Sepsis is a term referring to a condition free of pathogenic microorganisms or a procedure or process designed to prevent entry of infectious agents.
false (this is asepsis)
_______________ is an aqueous solution of formaldehyde gas that is used as a potent chemical fixative and microbicide.
formalin
The two aldehydes used most often in microbial control are __________ and ____________.
glutaraldehyde and formaldehyde
Ionizing radiation is a good technique for sterilizing material that are sensitive to ______________ or _____________.
heat or chemicals
The property of having antimicrobial effects in exceedingly small amounts belongs to which class of chemicals?
heavy metals
___________ _____________ typically kills microbes by producing toxic free radicals.
hydrogen peroxide
Plasmolysis of bacteria in food occurs when high concentrations of salt or sugar are added to the foods creating a __________ environment.
hypertonic
Which of the following is the practical definition of microbial death?
inability to reproduce
A virucide _________ viruses.
inactivates
_____________ is a dry heat that is commonly used in student laboratories to sterilize inoculating loops and wires.
incineration
____________ are complexes of iodine and alcohol
iodophors
Ethyl and ____________ alcohols are effective in microbial control.
isopropyl
Fungicides _____ fungal spores, hyphae, and yeasts.
kill
A bactericide __ bacteria.
kills
Filtration is used to prepare ______________ that cannot be heated, and to remove ____________ contaminants that are common source of infection and spoilage.
liquids; airborne
Cationic detergents disrupt the cell _____________ leading to a loss of selective permeability.
membrane
____________ involves the permanent termination of a particular organism's vital processes, and special qualifications are often needed to define and delineate this phenomenon in microbes.
microbial death
Phenolics are
microbicidal
Any process or agent that inhibits microbial growth is referred to as _____.
microbistatic
the normal 3-dimesional state of a protein is called its _____________ state.
native
__________ radiation is a method of microbial control that causes the formation of abnormal bonds within the DNA of microbes, increasing the rate of mutation.
nonionizing
The two broad categories that describe methods for controlling microbes are
physical and chemical
A ____________ _____________ is the union of 2 adjacent pyrimidines on the same DNA strand, brought about by exposure to ultraviolet light.
pyrimidine dimer
______ is a decontamination technique that mechanically removes microorganisms and debris from inanimate objects such as utensils to reduce contamination to safe levels.
sanitization
_________ is defined as growth of microorganisms in the blood or other tissues.
sepsis
The main effect of cold treatment is to __________ the activity of microbes.
slow
_________ objects are more reliably disinfected with a germicide.
smooth
__________ is an alkaline compound made by combining the fatty acids in oils with sodium or potassium salts.
soap
Household bleach is known by its chemical name
sodium hypochlorite
A ____________ is an agent that can destroy bacteria endospores.
sporicide
A process that completely removes or destroys all viable microorganisms, including viruses, from an object or habitat is referred to as ____________.
sterilization
Disinfectants are normally used on inanimate objects because
the high concentration needed are harmful to living tissues
One of the most widely used phenolics used today is ________.
triclosan
True or False: The lowest temperature that achieves sterilization in a given quantity of broth culture upon a 10-minute exposure is referred to as the thermal death point.
true
True or False: The primary targets of microbial control are microorganisms that cause infection or spoilage.
true
True or false: Acids or alkalis are limited in their application by their corrosive and hazardous nature.
true
True or false: An agent's effect on cells is known as its mode of action.
true
True or false: An autoclave is a sterilization chamber that allows the use of steam under pressure to sterilize materials.
true
True or false: Antimicrobial solutions with alcohols or water-alcohol mixtures as the solvent are called tinctures
true
True or false: Quats are rated for only low-level disinfection in the clinical setting.
true
True or false: Radiation is energy emitted from atomic activities and dispersed at high velocity through matter or space.
true
True or false: The necessity of sterilization or disinfection should be considered when initially choosing a method of microbial control.
true
Which of the following is/are types of nonionizing radiation?
ultraviolet rays