ICAR AIEEA-PG Dairy Processing Equipment: practice questions

ICAR AIEEA-PG: Dairy Science (group 16) and Dairy Technology (group 17) · India · NTA for ICAR

Original practice questions written to the published syllabus · not past papers

10worked here, free

34written to this exam in this subject

13syllabus units

What this subject covers

Construction, operation, care and sizing of the machines in a milk plant: tanks, separators, homogenisers, pasteurisers, sterilisers and fillers.

In the exams: ICAR AIEEA-PG group 17 Unit II (homogeniser, pasteuriser, steriliser, mixing and agitation); ICAR AICE subject 38 Unit 5

Sanitary design features and materials of dairy equipment
Milk storage tanks and silos
Centrifugal separators and clarifiers
Homogenisers: triplex pump, valves, two-stage operation, care
Plate heat exchangers: regeneration, holding tube, flow diversion valve
Tubular and scraped-surface heat exchangers
UHT plants: direct steam injection and infusion; indirect systems
Retorts and in-container sterilisers
Mixing and agitation equipment
Butter churns and continuous butter makers
Cheese vats, curd makers and moulding systems
Ice cream freezers
Filling and packaging machines

What ICAR AIEEA-PG asks from it

ICAR AIEEA-PG — Dairy Technology (group 17)

Unit II: materials and sanitary features of dairy equipment; homogeniser theory, triplex pump, lubrication, care, accessories and standards; pasteuriser construction and materials, HTST, care; sterilisers; mixing and agitation; principles of evaporation and drying equipment. Expect direct MCQs on parts, functions and care of each machine.

Where the 34 questions fall

How our questions for ICAR AIEEA-PG spread across the units of Dairy Processing Equipment. Difficulty: 22 easy, 12 medium, 0 hard.

Homogenisers: triplex pump, valves, two-stage operation, care	7
Milk storage tanks and silos	4
Ice cream freezers	3
Filling and packaging machines	3
Sanitary design features and materials of dairy equipment	3
Centrifugal separators and clarifiers	3
Plate heat exchangers: regeneration, holding tube, flow diversion valve	2
Tubular and scraped-surface heat exchangers	2
Mixing and agitation equipment	2
Butter churns and continuous butter makers	2
UHT plants: direct steam injection and infusion; indirect systems	1
Retorts and in-container sterilisers	1
Cheese vats, curd makers and moulding systems	1

10 practice questions, worked

Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.

1 · Milk storage tanks and silos · easy

What is the volume of a vertical cylindrical silo 4 m in diameter and 10 m high?

40.0 m³
251.3 m³
125.7 m³
502.7 m³

Answer and working

C. 125.7 m³

V = π × 4² ÷ 4 × 10 = 125.7 m³. 502.7 uses diameter as radius; 40.0 ignores π and the area; 251.3 divides D² by 2 instead of 4.

Further reading: Tetra Pak, Dairy Processing Handbook

2 · Milk storage tanks and silos · easy

Why is milk in silos agitated gently rather than vigorously?

To heat the milk by friction
To separate cream at the top
To incorporate air for later whipping into cream
To prevent creaming without foaming or fat damage

Answer and working

D. To prevent creaming without foaming or fat damage

Vigorous agitation causes foam and lipolysis.

Further reading: Tetra Pak, Dairy Processing Handbook

3 · Homogenisers: triplex pump, valves, two-stage operation, care · easy

Why must a homogeniser never run against a closed outlet?

Its motor is too weak to start against milk
It is a positive-displacement pump
The milk would freeze
The valve would open by itself

Answer and working

B. It is a positive-displacement pump

Pressure would build until something fails; a relief valve is fitted.

Further reading: Tetra Pak, Dairy Processing Handbook

4 · Plate heat exchangers: regeneration, holding tube, flow diversion valve · easy

Plate heat exchangers are best suited to:

Drying powders
Low-viscosity liquids without particles
Very viscous pastes with large particles
Gas cooling in refrigeration plants

Answer and working

B. Low-viscosity liquids without particles

Narrow channels limit PHEs.

Further reading: Tetra Pak, Dairy Processing Handbook

5 · Retorts and in-container sterilisers · easy

Why must steam retorts be vented before timing begins?

Remove air causing cold spots
To raise the pressure above 10 bar
To add oxygen for sterilisation
To cool the cans

Answer and working

A. Remove air causing cold spots

Air pockets reduce heat transfer.

Further reading: Tetra Pak, Dairy Processing Handbook

6 · Mixing and agitation equipment · easy

Which agitator suits viscous products in jacketed kettles?

Anchor with scrapers
High-speed propeller
Marine propeller with baffles
Static mixer

Answer and working

A. Anchor with scrapers

Anchors sweep the wall and aid heat transfer.

Further reading: Tetra Pak, Dairy Processing Handbook

7 · Butter churns and continuous butter makers · easy

Batch butter churns are filled with cream to about:

Completely full to the lid
Ninety per cent
One-tenth
Half their volume

Answer and working

D. Half their volume

Space is needed for agitation and air.

Further reading: Tetra Pak, Dairy Processing Handbook

8 · Butter churns and continuous butter makers · medium

In continuous butter makers, butter grains form in:

A vacuum pan
A slowly rotating drum over hours
A high-speed beater cylinder
A spray chamber

Answer and working

C. A high-speed beater cylinder

Grains form within seconds.

Further reading: Tetra Pak, Dairy Processing Handbook

9 · Cheese vats, curd makers and moulding systems · easy

In traditional open cheese vats, curd is cut with:

Wire harps
Homogenising valves
Paring discs
Dasher blades

Answer and working

A. Wire harps

Harps with wires cut the coagulum into cubes.

Further reading: Tetra Pak, Dairy Processing Handbook

10 · Ice cream freezers · easy

A continuous ice cream freezer is cooled by:

Steam condensing in its jacket
Ambient air
Hot water
Evaporating refrigerant

Answer and working

D. Evaporating refrigerant

Ammonia or halocarbons evaporate at low temperature.

Further reading: Tetra Pak, Dairy Processing Handbook

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