Chapter 11 – Flashcards

Microbiological contaminants are best described as: unwanted microbes present on or in a substance. any and all microbes present on or in a substance. pathogenic microbes present on or in a substance. vegetative microbes present on or in a substance. None of the choices are correct.

Physical agents for controlling microbial growth include all of the following, except: ultraviolet radiation. boiling water. HEPA filters. pasteurization. hydrogen peroxide.

Which of the following microbial forms have the highest resistance to physical and chemical controls? naked viruses protozoan cysts fungal spores bacterial endospores yeast

The process that destroys or removes all microorganisms and microbial forms including bacterial endospores is: disinfection. sterilization. antisepsis. sanitization. degermation.

The process of using a cleansing technique to mechanically remove and reduce microorganisms and debris to safe levels is: disinfection. sterilization. antisepsis. sanitization. degermation

The use of a physical or chemical process to destroy vegetative pathogens on inanimate objects is: disinfection. sterilization. antisepsis. sanitization. degermation.

The use of chemical agents directly on exposed body surfaces to destroy or inhibit vegetative pathogens is: disinfection. sterilization. antisepsis. sanitization. degermation.

Scrubbing or immersing the skin in chemicals to reduce the numbers of microbes on the skin is: disinfection. sterilization. antisepsis. sanitization. degermation.

Which is correct regarding the rate of microbial death? cells die at increasingly greater rates only older cells die in a culture cells in a culture die at a constant rate upon contact with the control agent, all cells die at one time cells become metabolically inactive but are never killed

Sterilization is achieved by: flash pasteurization. hot water. boiling water. steam autoclave. All of the choices are correct.

Dry heat: is less efficient than moist heat. cannot sterilize. includes tyndallization. is used in devices called autoclaves. will sterilize at 121° C for 15 minutes.

Endospores can be killed by: dry heat at 170° C for 2 hours. incineration. glutaldehyde for 3 or more hours. ethylene oxide for 3 or more hours. All of the choices are correct

The minimum sterilizing conditions in a steam autoclave are: 121° C at 15 psi for 15 minutes. 63° C for 30 minutes. 160° C for 2 hours. 71.6° C for 15 seconds. 100° C for 30 minutes.

The shortest time required to kill all the microbes in a sample at a specified temperature is called the: thermal death point (TDP). thermal death time (TDT). sporicidal time. death phase point. None of the choices are correct.

Disinfection of beverages, such as apple juice, milk, and wine, is optimally achieved by: pasteurization. chlorination. moist heat autoclave. filtration. boiling water.

Electrons are ejected from atoms in cells when organisms are exposed to: dessication. ultraviolet light. ethyl alcohol. hydrogen peroxide. gamma rays and X rays.

Which of the following items are typically irradiated in order to kill microbes? ground beef and other meat and poultry human tissues such as heart valves and skin operating room air surgical gloves All of the choices are correct.

HEPA filters are used to remove microbes from: air. liquids. human tissues. medical instruments. All of the choices are correct.

Which of the following does not contain a heavy metal? Tincture of iodine Merthiolate Silver nitrate solutions Zinc Mercurochrome

The easiest microbial forms to kill or inhibit are: naked viruses. vegetative bacteria and fungi. endospores. protozoan cysts. Mycobacterium and Staphylococcus.

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: Carbolic acid. Chlorhexidine. Triclosan. Formalin. Quarternary ammonium compounds.

Alcohols: denature proteins when in a 50-95% solution. are used to disinfect items by soaking. are skin degerming agents. at 50% or higher concentrations dissolve cell membrane lipids. All of the choices are correct.

All of the following are correct about iodophors, except: they are complexes of iodine and a neutral polymer. this formulation allows a quick release of free iodine. this formulation increases its penetration. it is less prone to staining or irritating tissue. a common iodophor is Betadine.

The sterilizing gas used in a special chamber is: ethylene oxide. iodophor. glutaraldehyde. formaldehyde. chlorine dioxide.

The chemical agent that produces highly reactive hydroxyl-free radicals and also decomposes to O2 gas is: Cidex. Cationic detergents. Hydrogen peroxide. Chlorhexidine. Iodophors.

All the following are correct about detergents, except: they are polar molecules that act as surfactants. the most effective ones are positively charged. in low concentrations they are bacteriostatic. they are ineffective against the tuberculosis bacteria. they are active in the presence of organic matter.

Ethylene oxide is: sporicidal. only effective with high heat. the active agent in household bleach. used as an antiseptic against anaerobes. a halogen.

Which of the following is being used to replace hypochlorites in treating water because of the possibility of cancer-causing substances being produced? hydrogen peroxide chloramines fluorine quaternary ammonium compounds sodium iodide

Which of the following chemicals is a disinfectant for soft contact lenses? hydrogen peroxide alcohol hexachlorophene glutaraldehyde hypochorites

Which of the following is officially accepted as a sterilant and high-level disinfectant? benzalkonium chloride silver nitrate glutaraldehyde triclosan cresol

All of the following are correct about food irradiation, except: food is not made radioactive by the process. the World Health Organization does not endorse this process. it is approved in the U.S. for beef, chicken, and pork. it can lead to a longer shelf life for the irradiated food. no irradiated food can be sold without clear labeling.

All of the following are benefits of food irradiation, except: it can kill bacterial pathogens on the food. it can kill insects on the food. it can inhibit the sprouting of white potatoes. it can reduce the number of food-borne deaths each year. it makes the food less nutritious.

All of the following are methods of disinfection or sterilization, except: gamma radiation. dry oven. lyophilization. triclosan. ethanol.

Historically, which of the following was instilled into the eyes of newborn infants to prevent gonococcal infections? triclosan formaldehyde phenol silver nitrate mercurochrome

Which common hospital pathogen is able to grow abundantly in soap dishes? Escherichia coli Pseudomonas Hemophilus influenzae Mycobacteria tuberculosis Salmonella

All of the following are correct about the autoclave, except: it is important not to overload the chamber. it is effective for sterilizing powders, oils, and waxy substances. the duration of the process depends on how full the chamber is. it is the temperature that kills the microbes, not the pressure by itself. sterilization is achieved when steam condenses against the objects in the chamber and raises their temperatures.

Which of the following types of agents targets protein conformation? Detergents Ultraviolet light Alcohol Hydrogen peroxide Crystal violet

Using toilet bowl cleaner and nonionizing radiation to inanimate surfaces only removes or kills vegetative bacteria. The term that best describes this action is: Sterilization Disinfection Antisepsis Degermation None of these are correct

Which of these metals have antimicrobial properties associated with them? Silver Gold Tin Aluminum Both A and B are correct.

Commercial products containing which types of chemicals are more effective at killing microorganisms? bacteriostatic bacteriocidal carbohydrate lead None of these are correct.

Bacteriocidal agents are sterilants. True False

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

Most 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

_____ heat is more rapidly effective and efficient compared to _____ heat.

Vials of microorganisms that undergo the freeze-drying process called _____ will remain preserved and viable for years.

A method for sterilizing milk, called _____ temperature treatment, uses 134° C for 1 to 2 seconds.

_____ radiation excites atoms to a higher energy state within molecules such as DNA that then leads to the formation of pyrimidine dimers.

Some microbial control agents are able to _____ cell proteins by breaking bonds that maintain the native state, three-dimensional configuration of the proteins.

_____ filters are widely used to provide a flow of sterile air to hospital rooms.

_____ is a halogen used in gaseous and liquid form for large scale disinfection of drinking water and sewage.

__________ or steam sterilization is the process by which steam is heated under pressure to sterilize objects.