ICAR AIEEA-PG Milk Composition & Physical Properties: practice questions

1 · Species differences: cow, buffalo, goat, sheep, camel, human · medium

Which protein is absent from both human and camel milk but is the main whey protein of cow milk?

1. Alpha-lactalbumin
2. Lactoferrin
3. Serum albumin
4. Beta-lactoglobulin

2 · Variation with breed, feed, season, lactation stage and mastitis · easy

Compared with fore-milk, the strippings at the end of milking are:

1. Similar in every constituent
2. Much richer in lactose
3. Much richer in fat
4. Much lower in fat and protein

3 · Colostrum and abnormal milks · easy

Which constituent is present at a much lower concentration in first-milking colostrum than in normal milk?

1. Total protein
2. Vitamin A
3. Immunoglobulin
4. Lactose

4 · Colostrum and abnormal milks · medium

A farm uses a hydrometer-type colostrometer to check colostrum. What property does it actually measure?

1. Electrical conductivity, which rises in direct proportion to the immunoglobulin content
2. Refractive index, which falls as immunoglobulin content rises
3. Specific gravity, which rises with immunoglobulin and total solids content
4. Viscosity, read from the time taken to drain a fixed volume

5 · Density and specific gravity; lactometer readings · medium

Using Richmond's formula for readings at 60 degrees Fahrenheit, what is the SNF of milk with 3.5 per cent fat and a corrected lactometer reading of 26.6?

1. 7.53 per cent
2. 7.39 per cent
3. 11.03 per cent
4. 6.79 per cent

6 · Viscosity, surface tension and interfacial tension · easy

Which milk component contributes most to the viscosity of whole milk?

1. Soluble salts
2. Whey proteins
3. Casein micelles
4. Lactose

7 · Electrical conductivity, refractive index and thermal properties · easy

The refractive index of milk at 20 degrees Celsius is about:

1. 1.344 to 1.348
2. 1.333
3. 1.500 to 1.520
4. 1.454 to 1.462

8 · Electrical conductivity, refractive index and thermal properties · easy

The specific heat of whole milk is about:

1. 1.0 kilojoule per kilogram per kelvin
2. 3.9 kilojoules per kilogram per kelvin
3. 2.1 kilojoules per kilogram per kelvin
4. 4.18 kilojoules per kilogram per kelvin

9 · Electrical conductivity, refractive index and thermal properties · medium

In a clean-in-place system, conductivity probes are mainly used to:

1. Measure the fat content of milk left in the pipes after rinsing
2. Measure the viscosity of the caustic solution during circulation
3. Detect bacterial spores remaining on stainless steel surfaces
4. Distinguish product, rinse water and detergent and control changeover

10 · Species differences: cow, buffalo, goat, sheep, camel, human · easy

Camel milk is notably richer than cow milk in which vitamin?

1. Vitamin D
2. Vitamin B12
3. Vitamin A
4. Vitamin C