59 terms

Chapter 11 - Microbial Control

1. Microbiological contaminants are best described as:
unwanted microbes present on or in a substance
2. Physical agents for controlling microbial growth include all of the following, except:
E. hydrogen peroxide.
Which of the following microbial forms have the highest resistance to physical and chemical controls?
D. bacterial endospores
The process that destroys or removes all microorganisms and microbial forms including bacterial endospores is:
B. sterilization.
The process of using a cleansing technique to mechanically remove and reduce microorganisms and debris to safe levels is:
D. sanitization.
The use of a physical or chemical process to destroy vegetative pathogens is:
A. disinfection.
The use of chemical agents directly on exposed body surfaces to destroy or inhibit vegetative pathogens is:
C. antisepsis.
Scrubbing or immersing the skin in chemicals to reduce the numbers of microbes on the skin is:
Which of the following types of control agents would be used to achieve sterility?
Which is correct regarding the rate of microbial death?
cells in a culture die at a constant rate
Sterilization is achieved by:
steam autoclave
Dry heat:
is less efficient than moist heat
Endospores can be killed by:
all of the choices are correct
The minimum sterilizing conditions in a steam autoclave are:
A 121 c at 15 psi for 15 minutes
The shortest time required to kill all the microbes in a sample at a specified temperature is called the:
thermal death time (TDT).
Disinfection of beverages, such as apple juice, milk, and wine, is optimally achieved by:
Electrons are ejected from atoms in cells when organisms are exposed to:
gamma rays and X rays
Which of the following items are typically irradiated in order to kill microbes?
all of the choices are correct
HEPA filters are used to remove microbes from:
Which of the following does not contain a heavy metal?
tincture of iodine
Which of the following are phenols or phenolics, except:
The easiest microbial forms to kill or inhibit are:
vegetative bacteria and fungi
Which control method would not be a suitable choice for killing Mycobacteria in a capped culture tube?
ultraviolet (germicidal) light
All of the following pertain to hypochlorites, except:
found in iodophors.
Which of the following is not used as an antiseptic?
aqueous glutaraldehyde
Iodophors include:
The compound that is an organic base containing chlorine and two phenolic rings and is used increasingly for handscrubbing, neonatal washes, wound degerming, and prepping surgical skin sites is:
B. chlorhexidine.
All of the choices are correct. D. at 50% or higher concentrations dissolve cell membrane lipids.
Which is mismatched?
Merthiolate - silver
All of the following are correct about iodophors, except:
this formulation allows a quick release of free iodine.
The sterilizing gas used in a special chamber is:
ethylene oxide.
The chemical agent that produces highly reactive hydroxyl-free radicals and also decomposes to O2 gas is:
All the following are correct about detergents, except:
they are active in the presence of organic matter.
Ethylene oxide is:
A. sporicidal.
Which of the following is being used to replace hypochlorites in treating water because of the possibility of cancer-causing substances being produced?
B. chloramines
Which of the following chemicals is a disinfectant for soft contact lenses?
A. hydrogen peroxide
Which of the following is officially accepted as a sterilant and high-level disinfectant?
C. glutaraldehyde
All of the following are correct about food irradiation, except:
the World Health Organization does not endorse this process
All of the following are benefits of food irradiation, except:
E. it makes the food less nutritious.
All of the following are methods of disinfection or sterilization, except:
C. lyophilization.
Historically, which of the following was instilled into the eyes of newborn infants to prevent gonococcal infections?
D. silver nitrate
Which common hospital pathogen is able to grow abundantly in soap dishes?
B. Pseudomonas
All of the following are correct about the autoclave, except:
B. it is effective for sterilizing powders, oils, and waxy substances.
Which of the following types of agents targets protein conformation?
C. Alcohol
Using toilet bowl cleaner and nonionizing radiation to non-animate surfaces only removes or kills vegetative bacteria. The term that best describes this action is:
B. Disinfection
Which of these metals have antimicrobial properties associated with them?
A. Silver
Commercial products containing which chemicals are more effective at killing microorganisms?
A. bacteriocidal
Bacteriocidal agents are sterilant
Bacteriostatic agents kill bacterial cells. True False
The presence of organic matter such as saliva and pus can interfere with the actions of disinfectants.
True False
When a control agent targets the metabolic processes of microbial cells, active younger cells typically die more rapidly than older cells. True False
A microorganism that is not motile and has stopped metabolizing could be considered dead. True False
microbial contaminants of food are killed at freezing temperatures. True False
Filtration is an effective method to remove microbes from air and liquids.
True False
Chlorine compounds remain stable and effective in the presence of excess organic matter. True False
Aniline dyes like crystal violet have antimicrobial activity particularly against gram positive bacteria and some fungi. True False
Alcohols are more effective at inactivating enveloped viruses than naked viruses. True False
Isopropyl alcohol wiped across a skin site can sterilize it. True False
Chlorine dioxide and ethylene oxide are gaseous sterilants. True False