Biochem - Sterilization

Question 1

1. The sterilization method depends

Answer 1

1. Both (a) and (b)

Question 2

2. The specific death rate of an organism can be expressed as

Answer 2

2. ln⁡(2)/Dln(2)/D

Question 3

3. The interception efficiency can be expressed as (wheredpdp​is the particle diameter andDCDC​cylindrical collection diameter).

Answer 3

3. dp/DCdp​/DC​

Question 4

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

Answer 4

4. Δ=A.t.eERTΔ=A.t.eRTE​

Question 5

5. The del factor (ΔΔ) increases as the final number of cells

Answer 5

5. Increases

Question 6

6. The overall del factor (ΔΔ) may be represented as

Answer 6

6. Δoverall=Δheating+Δholding+ΔcoolingΔoverall​=Δheating​+Δholding​+Δcooling​

Question 7

7. The filter material used for air filtration system is/are

Answer 7

7. All of the above

Question 8

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

Answer 8

8. Dispersion model

Question 9

9. The collection efficiency by diffusion increases with

Answer 9

9. Both (a) and (b)

Question 10

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

Answer 10

10. Lower pressure drop and are less liable to wetting or combustion

Question 11

11. The collection efficiency by interception increases with the

Answer 11

11. Increasing particle diameter

Question 12

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

Answer 12

12. Larger heat transfer area

Question 13

13. The mechanism of air filtration in fibrous filter is

Answer 13

13. All of the above

Question 14

14. If the packing density (aa) is defined as the volume of the fiber unit volume of filter bed, the velocity with the filter void space is equal to (whereV1V1​is velocity in fluid void space andV0V0​is undisturbed fluid velocity).

Answer 14

14. V=V0/(1−α)V=V0​/(1−α)

Question 15

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

Answer 15

15. Reynolds number

Question 16

16. In sterilization process, more of which of the following organism is considered as control?

Answer 16

16. Bacillus stearothermophilus

Question 17

17. Analogus to the molecular diffusion, the x-directional flux or microorganisms suspended in a medium due to the axial mixing can be represented as (whereJnJn​is flux component ‘n’,cncn​is concentration of ‘n’)

Answer 17

17. Jn=−Ddcn/dxJn​=−Ddcn​/dx

Question 18

18. The typical size of particles collected by diffusion mechanism is

Answer 18

18. <0.5 μm

Question 19

19. TheX90X90​value for a filtration system is

Answer 19

19. The depth required to reduce population by 90%

Question 20

20. The value of K

Answer 20

20. Increases to an optimum with increase in air velocity and decreases on further increase of air velocity

Question 21

21. Model proposed by the Friedlander, correlating the air filtration efficiency by impaction can be expressed as (whereNSfNSf​is the Stokes number).

Answer 21

21. ηimp=0.075Nst2ηimp​=0.075Nst2​

Question 22

22. The collection efficiency by impaction increases with

Answer 22

22. Both (a) and (b)

Question 23

23. The efficiency of fibrous filter by combined mechanism is given by (whereηimp,ηint,ηdirηimp​,ηint​,ηdir​are the efficiencies by impaction, interception, and diffusion, respectively).

Answer 23

23. 1−(1−ηimp)(1−ηint)(1−ηdir)1−(1−ηimp​)(1−ηint​)(1−ηdir​)

Question 24

24. The heat conduction in dry air is

Answer 24

24. Less rapid than in steam

Question 25

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

Answer 25

25. 0.5

Question 26

26. The reduction of number of cells from10101010to one will result into the del factor (A) of

Answer 26

26. 23

Question 27

27. Sterilization can be carried out by

Answer 27

27. All of these

Question 28

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

Answer 28

28. Stokes and Reynolds number

Question 29

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

Answer 29

29. Isothermal conditions

Question 30

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

Answer 30

30. 121°C

Question 31

31. The K used in the equation forX10=2.303/KX10​=2.303/Kdepends upon

Answer 31

31. Both (a) and (b)

Question 32

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

Answer 32

32. Radiation

Question 33

33. The radius of the filter with a depth of 14 cm required for a volumetric airflow rate of 10 m33/min is approximately

Answer 33

33. 0.6 m

Question 34

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

Answer 34

34. Decreased in a wet state

Question 35

35. The destruction of microorganisms by steam may be described as

Answer 35

35. First order chemical reaction

Question 36

36. Typical aeration rates for aerobic fermentation are

Answer 36

36. 1.0 – 1.5 vvm