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Sterilization MCQ Questions & Answers

Sterilization MCQs : This section focuses on the "Sterilization". These Multiple Choice Questions (MCQs) should be practiced to improve the Sterilization skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.




Question 1

_______ is the quickest way to sterilize solutions without heating.

A. Filtration
B. Chemical method of sterilization
C. Steam Sterilization
D. Chlorine dioxide gas

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Question 2

Which of the following is target microbe in commercial sterilization?

A. Pseudomonas aeruginosa
B. Bacillus anthracis
C. Salmonella typhi
D. Clostridium botulinum

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Question 3

The heat conduction in dry air is

A. less rapid than in steam
B. more rapid than in steam
C. similar to steam
D. none of these

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Question 4

The collection efficiency by the inertial impaction mechanism is the function of

A. Stokes and Reynolds number
B. Stokes and Schmidt number
C. Grashoff and Reynolds number
D. Stokes and Grashof number

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Question 5

The sterilization of ________ is generally carried out by retorts.

A. low carbohydrate foods
B. low acid foods
C. high acid foods
D. medium acid foods

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Question 6

_______ is used for sterilizing metallic devices like needles, scalpels.

A. Flaming
B. Incineration
C. Hot air oven
D. Steam

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Question 7

The typical size of particles collected by diffusion mechanism is

A. <0.25μm
B. <0.5μm
C. <0.75μm
D. <1μm

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Question 8

The relationship between the del factor, temperature and time is given as

A. Δ = A.t. e^-E/RT
B. Δ = 1/(A.t. e^-E/RT)
C. Δ = A.t. e^E/RT
D. Δ = A.t.T

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Question 9

The highest temperature which appears to be feasible for batch sterilization is

A. 121°C
B. 100°C
C. 105°C
D. 130°C

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Question 10

The sterilization method depends

A. nature of additive
B. volume and feed rate
C. both (a) and (b)
D. none of these

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Question 11

Model proposed by the Friedlander, correlating the air filtration efficiency by impaction can be expressed as (where NSt is the Stokes number)

A. ηimp = 0.075NSt^1.2
B. ηimp = 0.75NSt^1.2
C. ηimp = 0.25NSt^1.2
D. ηimp = 0.025NSt^1.2

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Question 12

The interception efficiency can be expressed as (where dp is the particle diameter and Dc cylindrical collection diameter)

A. dp/Dc
B. dp x Dc
C. dp/Dc x 100
D. dpDc/100

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Question 13

In sterilization process, spore of which of the following organism is considered as control?

A. Bacillus subtilis
B. Clostridium botulinum
C. Bacillus stearothermophilus
D. Aspergillus niger

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Question 14

The collection efficiency by interception increases with the

A. increasing particle diameter
B. increasing air flow velocity
C. both (a) and (b)
D. increasing particle size

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Question 15

Typical aeration rates for aerobic fermentation are

A. 0 - 0.5 vvm
B. 0.5 - 1.0 vvm
C. 1.0 - 1.5 vvm
D. 1.5 - 2.0 vvm

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Question 16

The X90 value for a filtration system is

A. the time required to reduce microbial population by 90%
B. the time required to traverse survivor curve by one log cycle.
C. the depth required to reduce population by 90%
D. the depth of the filter required to reduce population by 99%

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Question 17

The heat conduction in dry air is

A. less rapid than in steam
B. more rapid than in steam
C. similar to steam
D. None of the above

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Question 18

____________ is used for sterilizing inoculating loops.

A. Flaming
B. Incineration
C. Hot air oven
D. Steam

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Question 19

Analogus to the molecular diffusion, the x-directional flux of microorganisms suspended in a medium due to the axial mixing can be represented as (where Jn is flux component 'n', cn is concentration of'n')

A. Jn = -dcn/dx
B. Jn = dcn/dx
C. Jn = -D dcn/dx
D. Jn = D dcn/dx

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Question 20

The mechanism of air filtration in fibrous filter is

A. electrostatic attraction
B. impaction
C. interception
D. all of these

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Question 21

The collection efficiency by impaction increases with

A. increasing particle diameter
B. increasing air flow velocity
C. Both A and B
D. increasing particle size

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Question 22

The value of K

A. increases with increase in air velocity
B. decreases with increase in air velocity
C. increases to an optimum with increase in air velocity and decreases on further increase of air velocity
D. None of the above

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Question 23

The destruction of microorganisms by steam may be described as

A. first order chemical reaction
B. zero order chemical reaction
C. second order chemical reaction
D. none of these

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Question 24

Where should a sterilization indicator placed in an autoclave?

A. At the center
B. Close to lid of the autoclave
C. Sides of the autoclave
D. Anywhere inside the autoclave

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Question 25

The collection efficiency by impaction increases with

A. increasing particle diameter
B. increasing air flow velocity
C. both (a) and (b)
D. increasing particle size

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Question 26

For indirect heating, the plate and frame heat exchanger is generally more effective than the shell and tube heat transfer due to its

A. larger heat transfer area
B. smaller heat transfer area
C. lesser cost
D. more number of plates

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Question 27

Glass fibers are favorable as a filter medium because they give a

A. lower pressure drop and are less liable to wetting or combustion
B. more pressure drop and are less liable to wetting or combustion
C. lower pressure drop and are more liable to wetting or combustion
D. more pressure drop and are more liable to wetting or combustion

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Question 28

The value of K

A. increases with increase in air velocity
B. decreases with increase in air velocity
C. increases to an optimum with increase in air velocity and decreases on further increase of air velocity
D. none of these

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Question 29

If the packing density (α) is defined as the volume of the fiber unit volume of filter bed, the velocity within the filter void space is equal to (where V is velocity in fluid void space and V0 is undisturbed fluid velocity)

A. V = V0/(1-α)
B. V-V0 = 1 - α
C. V = V0(1 - α)
D. V = V0/(1 + α)

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Question 30

For laminar flow of Newtonian fluid through a smooth round pipe, the ratio of average fluid velocity to the maximum velocity is

A. 0.5
B. 0.75
C. 0.87
D. 0.37

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Question 31

The collection efficiency by interception increases with the

A. increasing particle diameter
B. increasing air flow velocity
C. Both A and B
D. increasing particle size

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Question 32

The mechanism of air filtration in fibrous filter is

A. electrostatic attraction
B. impaction
C. interception
D. All of the above

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Question 33

Does sterilization kill viruses?

A. TRUE
B. FALSE

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Question 34

The overall del factor (Δ) may be represented as

A. Δoverall = Δheating + Δholding- Δcooling
B. Δoverall = Δheating + Δholding+ Δcooling
C. Δoverall = Δheating - Δholding+ Δcooling
D. Δoverall = Δheating - Δholding- Δcooling

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Question 35

The collection efficiency by diffusion increases with

A. decreasing particle size
B. decreasing air velocity
C. both (a) and (b)
D. increasing particle size

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Question 36

The mechanical means of accomplishing sterilization of fermentation media/equipment is

A. ultrasonic
B. radiation
C. chemical agents
D. none of these

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Question 37

The specific death rate of an organism can be expressed as

A. ln 2/D
B. D/ln2
C. D.ln2
D. 2.0.3/ln2

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Question 38

The relationship between the del factor, temperature and time is given as

A. Δ = A.t. e-E/RT
B. Δ = 1/(A.t. e-E/RT)
C. Δ = A.t. eE/RT
D. Δ = A.t.T

View Answer

Question 39

Model proposed by the Friedlander, correlating the air filtration efficiency by impaction can be expressed as (where NSt is the Stokes number)

A. ηimp = 0.075NSt1.2
B. ηimp = 0.75NSt1.2
C. ηimp = 0.25NSt1.2
D. ηimp = 0.025NSt1.2

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Question 40

The efficiency of fibrous filter by combined mechanism is given by(where ηimp,ηint,ηdif are the efficiencies by impaction, interception and diffusion respectively)

A. 1 - ηimpηintηdif
B. 1 - (1 - ηimp)(1 - ηint)( 1 - ηdif)
C. 1 - ( ηimpηint/ηdif)
D. None of the above

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Question 41

The radius of the filter with a depth of 14 cm required for a volumetric airflow rate of 10 m3/min is approximately

A. 1.6 m
B. 0.6 m
C. 3
D. 6 m

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Question 42

The sterilization method depends

A. nature of additive
B. volume and feed rate
C. Both A and B
D. None of the above

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Question 43

The deviation from ideal plug flow due to axial mixing can be described by the

A. dispersion model
B. Langmuir model
C. Friedlander model
D. Pasceri model

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Question 44

The reduction of number of cells from 1010 to one will result into the del factor (Δ) of

A. 1
B. 10
C. 23
D. 103

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Question 45

The del factor (Δ) increases as the final number of cells

A. decreases
B. increases
C. zero
D. constant

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Question 46

Who developed steam sterilizer?

A. Louis Pasteur
B. Charles Chamberland
C. Nicolas Appert
D. Clarence Birdseye

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Question 47

The heated medium passes through a holding section, which is usually maintained in

A. adiabatic conditions
B. isothermal conditions
C. isotropic conditions
D. isobaric conditions

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Question 48

The filter material used for air filtration system is/are

A. glass wool
B. glass fibre
C. norite
D. All of the above

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Question 49

The collection efficiency by diffusion increases with

A. decreasing particle size
B. decreasing air velocity
C. Both A and B
D. increasing particle size

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Question 50

Sterilization can be carried out by

A. heat
B. radiation
C. chemical agents
D. all of these

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Question 51

For the turbulent flow, the dispersion coefficient is correlated as a function of

A. Reynolds number
B. Sherwood number
C. Schmidt number
D. Grashof number

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Question 52

The moist heat is more effective than the dry heat because the intrinsic heat resistance of vegetative cells is greatly

A. increased in a dry state
B. decreased in a dry state
C. increased in a wet state
D. decreased in a wet state

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Question 53

The K used in the equation for X10=2.303/K depends upon

A. nature of the filter material
B. linear velocity of the air passing through filter
C. both (a) and (b)
D. thickness of the filter

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