Multiple Choice Questions (MCQ) on Dairy Science (Part -2)

ANSWERS & EXPLANATIONS

  1

d. (Both a and c)

- Both lactose and fat are synthesized Denova in alveolar epithelium. 

2

b. (Jersey)

- Jersey’s milk is used for butter making while Haryana’s milk is used for Cheese making.

3

b. (Jersey)

• Highest fat % among exotic breed of cattle – Jersey
•  Fat % is higher in exotic breed of cattle than indigenous breed. 
• Fat % of exotic cattle – 4.6%

Milk Fat % of different Animals:

•  Cow - 4%
• Buffalo – 5.3%
• Doe- 4.5%
• Ewe- 7.4%

Water % in milk of different Animals

• Buffalo – 84.2%
• Exotic cow – 79.5%
• Indigenous cow- 87% 
• Skim milk- 90%

4

(Ca sensitive alpha1 casein)

• White color of milk is due to Ca- caseinate
• Yellow color of milk is due to carotene.
• Cow’s milk contains – 26mg carotene/gm of cow’s milk
• Whey is greenish yellow in color due to lactochrome
•  Skim milk is bluish- yellow in color.

5

d. (Early gestation period)

The development of mammary gland starts during early Gestation periods.

6

a. (Alpha – lactalbumin)

• Water soluble protein of milk is alpha- lactalbumin
• Alpha- lactalbumin is not coagulated by rennet and acids but by heat. 
• Casein constitutes 80% of total protein, Present as Ca- Caseinate Phosphate.

7

b. (Homogenized milk)

• Milk from which no cream can be separated- Homogenized milk
• Homogenization is the process of making stable emulsion of milk fat and milk serum by a mechanical treatment (Homogenizer)
• Size of fat globules of milk after homogenization – 4 microns 
• Minimum fat % required for 2 stage homogenization is at least above 6%

8

c. (Both Phospholipid and Milk protein)

• Both Phospholipid and milk protein are emulsifier of milk.
• Butter is example of water in fat emulsion while cream is example of fat in water emulsion.

9

b. (Isotonic)

• Milk and blood are Isotonic (According to osmotic pressure)
• Milk contains less water than blood plasma
• A constituent that found in milk, not blood is casein. 

10

b. (Higher)

• Bacterial count in machine milking is higher as compared to hand milking.
• Pressure required for machine milking: 25-40 mm of Hg
• Pulsation ratio of machine milking: (Vacuum phase time/ pressure phase time)
• Pulsation rate of machine milking: 40-120 cycles/min

11  

(30-36 degree C)

Melting Point of milk fat is 30 -36 degree C (exact: 33-33.5 degree C) 

12

d. Gerber method

• Volumetric method for determination of fat% in milk - Gerber method
• Gravimetric method for determination of fat% in milk- Soxhlet method 
• Method of determination of specific gravity of milk – Wastfall balance
• Method of determination of total solid in milk - Richmond Sliding method 

Richmond formula:

TS = 0.25Lactose + 1.2 Fat + 0.14

13

(Sour Curdling)

• Curdling of milk by admixture of acid – Sour Curdling
• Curdling of milk by admixture of rennet – sweet curdling (product – Cheese) 
• Rennet is made from S.I. of suckling calf
• Curdling of milk by admixture of citrate – ordinary Curdling (product – Paneer)
• Type of fermentation that occurs in milk after adding yeast – Alcoholic 
• Starter culture % for Dahi making: 2-3%

14

(Zeiss refractometer)

• Instrument used for measuring refractive index – Zeiss refractometer
• Instrument used to measure fat % in milk by gravimetric method – Soxhlet apparatus 
• Instrument used for vacuum pasteurization - Vacuum creator
• Instrument used for freezing point determination – Horvet cryoscope 
• Instrument used for measuring specific gravity of milk- Lactometer
• Instrument used for measuring cream content of milk – Babcock bottle  

15

a. (Diacetyl)

• Flavoring agent of butter is Diacetyl.
• Milk flavor results mainly from proteins, lipids, and carbohydrates, and small amounts of other components.
• Fat % of flavored milk is 1-2 % 

Different Flavors of Milk 

• Growth of bacteria: Fruity, malty and acid
• Lipase: Rancid
• Processed milk: cooked flavor due to sulfhydryl group 
• Oxidation: Cardboard flavor
• Dried milk: Tallow
• Other product: Metallic or paint 

16

d. Phosphatase test

Efficiency of pasteurization is measured by Phosphatase test

Test of milk

• Strip cup test - Mastitis
• Alcohol precipitation test and acidity test – Acidity of milk 
• Clot on boiling test - Heat stability
• Alizarin test  - pH and heat stability 
• Resazurin test, Reductase test, SPC test - Bacteriological count of milk
• Sedimentation test - Insoluble sediments of milk
• Hansa test - mixing of buffalo and cow milk

17

c. (Lactate bacteria)

In starter of the butter and the cheese, bacteriophage fed on lactate bacteria.

18

b. (35-40 degree C)

• Preheating temperature of milk before pasteurization – 35- 40 C 
• Preheating temperature before cream separation – 40-45 C
• Reconstituted milk is heated at temperature – 35-37 C
• Temperature and time for LTLT method of pasteurization- 63 degree C (143 F) for 30 min
•  Temperature and time for HTST method of pasteurization- 72 degree C (161 F) for 15 sec
• HTST method of pasteurization is better than LTLT method of pasteurization
• Organism of TB is destroyed at - 138-degree F
• Temperature of cream line reduction test – 144-degree F for 30 min
• Temperature for phosphatase inactivation – 142-degree F for 30 min
• Temperature and time for frozen concentrated milk – 4 degree C and 12 hrs.
• Bottle method temp and time – 63 degree C and 30 min
• Stassinization temp and time – 74 degree C and 7 sec
• Uperisation method temp and time - 150 degree C and ¾ second
• Flash method temp and time – 72 degree C and 15 second

19

d. (Hill curd tension test)

• Test for accessing sweet/sour curdling of milk – Hill curd tension test
• Starch adulteration can be detected by:  Iodine test
• Test for detection of adulteration of Ghee:  Tile test/ H2SO4 test/ Mustard oil test 
• Presence of sesame oil (Vanaspati ghee) in milk can be tested by: Baudoin test
• Test for mixing Cow and Buffalo milk: Hansa test
• Presence of antibiotics and Sulphur residues can be tested by: Delvotest kit 
• Presence of neutralizer is identified by Rosalic- acid test 
• Presence of gelatin: Picric acid test
• Presence of cane sugar: Resorcinol test
• Presence of glucose: Barfoed test
• Presence of skim milk powder: Nitric acid test

20

c. (Milk lipid)

-Lecithin is the component of milk lipid.  

21

c. (Copper)

Milk got oxidized if it stored in container of copper metal.  

22

b. (Twice a day)

Milking should be performed twice in a day.

23

 a. Continuous process

• Milk secretion is a continuous process.
• LTLT is the batch process and HTST is the continuous process.  

24

c. (400-500 ml)

400-500 ml blood should be passed for 1 ml of milk production.

25

d. (Both a and c) 

Both Peptonizing bacteria and Casein digesting bacteria are liquefier.

26

(Oxytocin)

• Hormone responsible for letdown of milk – Oxytocin and Pitocin
• Oxytocin hormone acts on basket cell for letdown of milk
• Basic milk secretary unit of udder – Alveoli
• Hormone responsible for holding up of milk – Adrenaline 
• Faster milking decreases holding of milk in udder
• Hormone responsible for initiation of milk secretion- Prolactin
• Growth hormone responsible for growth of animals, releases from Adenohypophyses
• Protein that used for increases in milk production – Iodinated casein

27

c. (Cheese)

• Cow’s milk is used for making (Kanchan) Cheese
• Sheep’s milk is used for making Roquefort cheese.
• Goat’s milk is used for making Cottage cheese.
• Buffalo’s milk is used for making Mozzarella cheese 
• Best substitute of human milk (best for infant): Goat’s milk

28

(Rackangel phenomenon)

• Specific gravity of milk is reduced one hr. after milking known as, Rackangel phenomenon.
• Hamburger phenomenon: Loss of bicarbonate ions from RBC causes positive charge inside RBC which is balanced by diffusion of chloride (Cl-) ion from plasma into the RBC. ... This phenomenon of chloride shift maintains the electrical neutrality of cell. This phenomenon is also known as Hamburger phenomenon.
• Donnan phenomenon: The Donnan is a name for the behavior of charged particles near a semi-permeable membrane that sometimes fail to distribute evenly across the two sides of the membrane. The usual cause is the presence of a different charged substance that is unable to pass through the membrane and thus creates an uneven electrical charge.

29

d. (All)

The preservatives for milk are Boric acid, Formalin, Sodium carbonate etc.

30

c. (Buffalo)

Red water disease is commonly found in Buffalo 

31

(Liq. N2)

• For long term storage of sperm, it is kept in Liquid Nitrogen.
• Temperature of Liquid nitrogen: - 196 degree C   

32

a. (Late) 

Fat % of milk increases during late lactation.  

33

c. (Both)

Both Fat and SNF are the important factor that determines the quality of milk.

34

 a. (Vit A)

• Colostrum is rich in Vit- A, cellular content, suitable for infants feeding, responsible for immunity development.
• As compared to milk, colostrum contains 5 times more Vit-A, 3 times more Vit-B2, 2 times more Vit- D and 6 times more Vit- E. 

35

c. (30,000)

• Maximum limit of SPC/ml for pasteurized milk – 30,000
• Maximum limit of SPC/ml for market milk – 1, 00,000 

Grading of milk according to pathogen count

• Very good milk - Less than 2 lakhs bacteria
• Good - 2- 10 lakhs 
• Fair - 10-50 lakhs
• Poor- More than 50 lakhs bacteria

36

 c. (220 grams khoa)

The liter of buffalo milk on average composition yields 220 grams Khoa

37

b. (Carbohydrate)

• Carbohydrate is the constituent of milk that mainly changed during its conversion into curd.
• Least variable constituent of milk: Lactose
• Constituent that affects freezing points of milk: Fat

38

d. All

• Ice – cream is the frozen product obtained from:
• Combination of milk product and cream
• Additional of cane sugar, eggs and fruits
• Edible flavor and food color
• Soft ice- cream is usually drawn from freezer at around (- 8C to 7C)
• The composition of soft ice cream- fat/SNF/ sugar/ Stabilizer and emulsifier
•  Defect in ice cream arises usually due to low quality ingredients, improper mixing, faulty method of manufacture and storage.

39

d. (All)

• Butter oil is termed as Milk fat, dry butter fat, anhydrous milk fat. 
• Butter oil is richest source of milk fat and Vit. A and D
• Butter should be stored at temp of 4 to 5 degree C

40

d. (Pre- stratification method)

Best method of preparation of Ghee – Pre – stratification method  

41

c. 16.3%

• Fat% in butter: Not less than 80%
• Fat% in cream: Not less than 25%
• Fat% in Ghee: Not less than 99%
• Fat% in Cheese: Not less than 42%
• Fat% in Ice- cream: Not less than 10%
• Fat% in milk Powder: Not less than 26%  

42

b. (Bleaching powder) 

• The common ingredient used in the preparation of solution for Sterilization of dairy Utensils is Bleaching powder 
• A good detergent for cleaning milk’s utensils should be alkaline.

43

a. (65 degree C)

• The Gerber butyrometer should be kept in hot water bath (65C) for determination of milk fat.
• The speed of Gerber centrifuge machine in fat test - 1100 rpm.

44

a. (3% fat and 8.5% SNF)

• Single toned milk should contain minimum of 3% fat and 8.5 % SNF
• Double toned milk should contain minimum of 1.5% fat and 9% SNF
• Standardized milk contains 4.5% fat and 8.5% SNF  

45

• Lactobacillus acidophil or bulgaricus
• Kumis’s culture consists of lactobacillus acidophil or bulgaricus
• Streptococcus bacteria is responsible for producing Sweet/sour cream.

Points to be known in Dairy Science:

• Milk: Clean lacteal secretion with SNF not less than (8.5%) and fat not less than (3.5%) after 72 hrs. of calving
• Most variable factor in milk: Fat while least variable factor: Lactose 
• Freezing point of milk - -0.5C while Boiling point of milk- 100.17 to 101 C

Note:

For Video: https://youtu.be/reLKHD6Rdmk

Since it's a part -2, For Multiple Choice Questions on Dairy Science (Part-1), visit site.