Question 1

Autoclaving will usually destroy/inactivate all fungi,bacteria,viruses,and most bacterial spores but will not necessarily eliminate
A)neurotoxins.
B)prions.
C)protozoan cysts.
D)mycoplasmas.

Accepted Answer

Autoclaving is not effective in eliminating prions as they are resistant to most conventional sterilization methods including autoclaving. Option A is incorrect as it does not relate to the question asked. Option C is partially correct as some protozoan cysts (such as those of Giardia and Cryptosporidium) may survive autoclaving. Option D is incorrect as mycoplasmas are typically destroyed by autoclaving.

Question 2

The cleaning of glassware and tableware in restaurants falls into the category of
A)degermation.
B)sterilization.
C)disinfection.
D)sanitization.

Accepted Answer

The cleaning of glassware and tableware in restaurants falls into the category of sanitization, which is the process of reducing the number of microorganisms on a surface to a safe level. While sterilization and degermation aim to completely eliminate all microorganisms, disinfection is focused on reducing the number of harmful microorganisms but does not necessarily eliminate them completely.

Question 3

All of the following are methods for food preservation except
A)Pasteurization
B)Disinfection
C)Irradiation
D)Ultrahigh-temperature pasteurization

Accepted Answer

Disinfection is not a method for food preservation. While disinfection may be used to sanitize surfaces and equipment in food production and processing, it is not a direct method for preserving food products. The other options listed (pasteurization, irradiation, ultrahigh-temperature pasteurization) are all methods used to preserve food by reducing or eliminating harmful microorganisms or enzymes.

Question 4

Boiling items in water for __________ minutes will kill most vegetative bacteria and viruses.
A)3-5
B)5-6
C)6-8
D)10-15

Accepted Answer

Boiling items in water for 10-15 minutes is generally recommended to ensure the destruction of most vegetative bacteria and viruses.

Question 5

The effects of different kinds of radiation depend on the following factors:
A)Time of exposure, wavelength
B)Intensity, frequency, thickness of sample
C)Distance, frequency, nature of sample
D)Chemical composition, intensity, shielding

Accepted Answer

The answer of The effects of different kinds of radiation...

Question 6

The food preparation process in which not all microorganisms are killed,but the number of microbes capable of spoiling the food or causing disease is reduced,is called
A)sanitation.
B)pasteurization.
C)disinfection.
D)purification.

Accepted Answer

The food preparation process described is pasteurization, which involves heating the food to a specific temperature for a specific period of time to reduce the number of harmful microorganisms without necessarily killing all of them. Sanitation involves cleaning and maintaining a clean environment to prevent the growth and spread of microorganisms, disinfection involves the use of chemicals or heat to kill all or most microorganisms, and purification involves removing impurities or contaminants from a substance.

Question 7

Chlorine belongs to which of the following chemical groups?
A)Halogens
B)Heavy metals
C)Phenols
D)Alcohols

Accepted Answer

Chlorine belongs to the halogen group, which includes elements such as fluorine, bromine, and iodine.

Question 8

The time in minutes in which 90% of the bacterial population will be killed at a given temperature is called the
A)generation time.
B)thermal death time.
C)sterilization time.
D)decimal reduction time.

Accepted Answer

The time in minutes in which 90% of the bacterial population will be killed at a given temperature is called the decimal reduction time. This concept is used in food industry to determine the level of processing required to ensure the safety of the food product. The thermal death time refers to the time required to completely kill all bacterial population at a given temperature, while sterilization time refers to the time required to completely eliminate all forms of microbial life, including bacterial spores. Generation time refers to the time required for a bacterial population to double in number.

Question 9

The term "zone of inhibition" is used in which of the following procedures?
A)Use-dilution test
B)Growth inhibition test
C)Disk-diffusion test
D)Multiple inhibition test

Accepted Answer

Zone of inhibition is a term used in the disk diffusion test, which measures the effectiveness of antimicrobial agents against a particular organism. In this test, a disk containing a specific concentration of an antimicrobial agent is placed on an agar plate that has been inoculated with the organism being tested. If the agent is effective, a clear area of no growth (zone of inhibition) will appear around the disk. The use-dilution test and multiple inhibition tests are also used to measure the effectiveness of antimicrobial agents, but they do not use the term "zone of inhibition." The growth inhibition test is a broad term used to describe any test in which the growth of microorganisms is measured, but it does not specifically refer to the disk diffusion test.

Question 10

The destruction of vegetative organisms by chemical or physical methods is called __________.

Accepted Answer

The answer of The destruction of vegetative organisms by chemical...

Question 11

Ionizing radiation involves all of the following except
A)UV light
B)Gamma rays
C)Electron beams
D)X-rays

Accepted Answer

UV light is a form of non-ionizing radiation, meaning it lacks enough energy to ionize atoms or molecules. The other options (B, C, and D) are all forms of ionizing radiation.

Question 12

The term to describe an agent that causes microbial growth to be inhibited,thus preventing further growth is __________.

Accepted Answer

The answer of The term to describe an agent that...

Question 13

The technique that combines freezing and drying to preserve microbes and other cells is
A)desiccation.
B)lyophilization.
C)pasteurization.
D)radiation.

Accepted Answer

The technique that combines freezing and drying to preserve microbes and other cells is lyophilization. Desiccation is the process of removing water from a substance through exposure to air, Pasteurization is a heating process to kill harmful bacteria in food, and radiation can be used to sterilize materials but is not specifically related to the preservation of microbial cells.

Question 14

Antimicrobial agents that are specifically designed to be used on living tissues are referred to as __________.

Accepted Answer

The answer of Antimicrobial agents that are specifically designed to...

Question 15

The lowest temperature by which all microorganisms in a particular liquid will be killed within 10 minutes is the __________.

Accepted Answer

The answer of The lowest temperature by which all microorganisms...

Question 16

Which of the following has a higher resistance to environmental stresses than the others?
A)Bacterial endospores
B)Fungal spores
C)Enveloped viruses
D)Vegetative bacterial cells

Accepted Answer

Bacterial endospores are known to have the highest resistance to environmental stresses such as high temperature, radiation, and chemical disinfectants compared to the other options listed. Fungal spores have some tolerance to environmental stresses, but not as much as bacterial endospores. Enveloped viruses are the least resistant, as they are easily destroyed by environmental stresses such as ultraviolet light, heat, and chemicals. Vegetative bacterial cells are also relatively fragile and can be easily destroyed by environmental stresses.

Question 17

Decontamination is defined as the
A)killing of all microorganisms in a given area.
B)reduction or removal of unwanted chemical or biological agents.
C)stopping of the growth of microorganisms in a given area.
D)removal of all vegetative organisms.

Accepted Answer

Decontamination involves the process of reducing or removing unwanted chemical or biological agents, such as toxins, bacteria, and viruses. This may include removing or neutralizing hazardous materials or disinfecting surfaces to reduce the risk of transmission of infectious agents. Killing all microorganisms in a given area (A) and removing all vegetative organisms (D) are not always necessary for effective decontamination and may not be feasible or practical in all situations. The stopping of the growth of microorganisms (C) also does not necessarily guarantee decontamination, as some microorganisms may still be present and pose a risk.

Question 18

Which of the following methods is the simplest heat-related method to sterilize metal?
A)Incineration
B)Autoclaving
C)Direct flaming
D)Indirect heating

Accepted Answer

Direct flaming is the simplest and quickest heat-related method to sterilize metal. This involves passing a metal object through a flame to kill any microorganisms present on its surface. It is commonly used in microbiology labs to sterilize inoculation loops and needles.

Question 19

A toxic,odorless gas often used as a sterilizing agent in hospitals and dental officials is
A)ethylene oxide.
B)carbon dioxide.
C)carbon monoxide.
D)propane.

Accepted Answer

Ethylene oxide is a commonly used gas for sterilization in hospitals and dental offices due to its effectiveness in destroying various microorganisms. It is odorless and highly toxic, requiring strict handling protocols and equipment to ensure the safety of workers and patients. Carbon dioxide is not typically used as a sterilizing agent, while carbon monoxide and propane are both highly toxic gases that are not used for sterilization purposes.

Question 20

Agents that kill microbes are classified as __________.

Accepted Answer

The answer of Agents that kill microbes are classified as...

Quiz 7: Physical and Chemical Methods of Control

Autoclaving will usually destroy/inactivate all fungi,bacteria,viruses,and most bacterial spores but will not necessarily eliminate

The cleaning of glassware and tableware in restaurants falls into the category of

All of the following are methods for food preservation except

Boiling items in water for __________ minutes will kill most vegetative bacteria and viruses.

The effects of different kinds of radiation depend on the following factors:

The food preparation process in which not all microorganisms are killed,but the number of microbes capable of spoiling the food or causing disease is reduced,is called

Chlorine belongs to which of the following chemical groups?

The time in minutes in which 90% of the bacterial population will be killed at a given temperature is called the

The term "zone of inhibition" is used in which of the following procedures?

The destruction of vegetative organisms by chemical or physical methods is called __________.

Ionizing radiation involves all of the following except

The term to describe an agent that causes microbial growth to be inhibited,thus preventing further growth is __________.

The technique that combines freezing and drying to preserve microbes and other cells is

Antimicrobial agents that are specifically designed to be used on living tissues are referred to as __________.

The lowest temperature by which all microorganisms in a particular liquid will be killed within 10 minutes is the __________.

Which of the following has a higher resistance to environmental stresses than the others?

Decontamination is defined as the

Which of the following methods is the simplest heat-related method to sterilize metal?

A toxic,odorless gas often used as a sterilizing agent in hospitals and dental officials is

Agents that kill microbes are classified as __________.