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Maharashtra SSC Milk & Milk Products (MSBSHSE) study materials
Maharashtra SSC Milk & Milk Products (MSBSHSE) study resources

Maharashtra SSC Milk & Milk Products (MSBSHSE) practice questions

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Question 1Milk: composition, physical and chemical properties

Fresh cow milk typically contains what percentage of water?

  1. About 65 percent
  2. About 87 percent Correct answer.
  3. About 50 percent
  4. About 96 percent

Explanation

Cow milk is roughly 87 percent water and about 13 percent total solids. The solids are split between fat (about 3.5 to 4.5 percent) and solids-not-fat such as lactose, protein and minerals. Water is the continuous phase in which all other milk constituents are dispersed or dissolved.

Question 2Milk: composition, physical and chemical properties

Which carbohydrate is the principal sugar naturally present in milk?

  1. Glucose
  2. Lactose Correct answer.
  3. Sucrose
  4. Maltose

Explanation

Lactose is a disaccharide of glucose and galactose and is the characteristic carbohydrate of mammalian milk, present at about 4.5 to 5.0 percent in cow milk. Sucrose, maltose and free glucose occur only in traces unless the milk has been adulterated or fermented.

Question 3Milk: composition, physical and chemical properties

Casein belongs to which class of milk proteins?

  1. Whey proteins
  2. Albumins soluble at pH 4.6
  3. Phosphoproteins precipitated at pH 4.6 Correct answer.
  4. Enzymes of the milk fat globule membrane

Explanation

Casein is a phosphoprotein that coagulates when milk is acidified to its isoelectric point near pH 4.6. It makes up about 80 percent of total milk protein and is organised in micelles with calcium phosphate. The remaining proteins stay soluble at that pH and are classed as whey proteins.

Question 4Milk: composition, physical and chemical properties

Milk fat is mainly composed of which type of lipid?

  1. Sterols
  2. Triglycerides Correct answer.
  3. Free fatty acids
  4. Phospholipids

Explanation

About 98 percent of milk fat is triglyceride, that is, glycerol esterified with three fatty acids. Phospholipids, sterols and free fatty acids occur only in small amounts. The fatty acid profile of these triglycerides governs the melting behaviour and hardness of butterfat.

Question 5Milk: composition, physical and chemical properties

The density of normal cow milk at 20 degrees Celsius lies closest to which value?

  1. 0.910 to 0.930 g per mL
  2. 1.000 to 1.005 g per mL
  3. 1.028 to 1.032 g per mL Correct answer.
  4. 1.100 to 1.120 g per mL

Explanation

Whole cow milk has a density near 1.030 g per mL at 20 degrees Celsius. The value is higher than water because dissolved lactose, salts and protein add mass, while dispersed fat lowers it slightly. A reading well below 1.028 suggests added water.

Question 6Milk: composition, physical and chemical properties

Which pigment gives cow milk its faint yellowish tint?

  1. Melanin
  2. Anthocyanin
  3. Chlorophyll
  4. Carotene Correct answer.

Explanation

Carotene, a fat-soluble provitamin A pigment derived from the fodder, dissolves in milk fat and imparts a creamy yellow colour. Jersey and Guernsey milk looks yellower because these breeds transfer more carotene into fat. Chlorophyll and anthocyanin are plant pigments not normally found in milk.

Question 7Milk: composition, physical and chemical properties

Boiling milk in an open pan produces a surface skin mainly because of which change?

  1. Evaporation of water and protein denaturation at the hot surface Correct answer.
  2. Separation of fat by churning
  3. Crystallisation of lactose
  4. Coagulation of casein by rennet

Explanation

At the hot surface water evaporates and whey proteins such as lactalbumin denature and complex with casein, forming a film. Continued heating thickens this film into the familiar skin. Rennet action, lactose crystallisation and churning are unrelated mechanisms.

Question 8Milk: composition, physical and chemical properties

Which mineral is present in the highest concentration in normal cow milk?

  1. Zinc
  2. Calcium Correct answer.
  3. Iron
  4. Copper

Explanation

Calcium is the most abundant mineral in milk, at roughly 120 mg per 100 mL, and much of it is associated with casein micelles. Potassium and phosphorus follow in abundance. Iron, zinc and copper are present only in traces, which is why milk is a poor source of iron.

Question 9Milk: composition, physical and chemical properties

When milk is allowed to stand undisturbed, cream rises to the top. This behaviour is best explained by which property?

  1. Higher viscosity of the fat layer
  2. Chemical reaction between fat and protein
  3. Lower density of fat than of the aqueous phase Correct answer.
  4. Osmosis of water into fat globules

Explanation

Milk fat is dispersed as globules of density near 0.93 g per mL in a serum of density near 1.03 g per mL. Buoyancy therefore drives the globules upward, a process called creaming. Homogenisation prevents this by reducing globule size so that Brownian motion keeps the fat suspended.

Question 10Milk: composition, physical and chemical properties

Addition of water to milk lowers which measured property most reliably?

  1. Refractive index of the serum
  2. Density
  3. Freezing point Correct answer.
  4. Titratable acidity

Explanation

Dissolved solutes depress the freezing point of milk to about minus 0.53 degrees Celsius, and dilution reduces this depression in proportion to the water added. Freezing point depression is therefore the basis of the official cryoscopic test for added water. Density can be misleading because fat removal raises it while watering lowers it.

Question 11Milk: composition, physical and chemical properties

Why does sour milk curdle when heated?

  1. Lactose crystallises and traps the protein
  2. Calcium phosphate dissolves completely and no protein remains
  3. Lactic acid lowers pH near the isoelectric point, destabilising casein micelles Correct answer.
  4. Fat melts and pushes casein out of the emulsion

Explanation

Lactic acid bacteria convert lactose to lactic acid, lowering pH toward 4.6, the isoelectric point of casein. At that pH the micelles lose their charge repulsion and aggregate, and heating accelerates the visible curdling. Fresh milk with normal pH withstands boiling without such coagulation.

Question 12Milk: composition, physical and chemical properties

Which statement correctly describes the pH of fresh normal cow milk?

  1. Alkaline, about 8.5
  2. Neutral, exactly 7.0
  3. Strongly acidic, about 4.6
  4. Slightly acidic, about 6.6 to 6.8 Correct answer.

Explanation

Fresh milk is slightly acidic with a pH between about 6.6 and 6.8, reflecting its dissolved phosphates, citrate and proteins. The pH falls during bacterial fermentation as lactic acid accumulates. Values near 4.6 indicate heavy souring, while pH above 7 suggests mastitis or added alkali.

Question 13Milk: composition, physical and chemical properties

Homogenisation of milk primarily changes which physical characteristic?

  1. It converts fat into protein
  2. It increases the average diameter of fat globules
  3. It removes fat from the milk serum
  4. It reduces fat globule size and increases the number of globules Correct answer.

Explanation

Homogenisation forces milk through a narrow valve at high pressure, shattering large fat globules into many small ones. The smaller globules stay suspended because Brownian motion counteracts creaming. The total fat content is unchanged; only the size distribution and surface area change.

Question 14Milk: composition, physical and chemical properties

A sample of milk shows a density of 1.020 g per mL at 20 degrees Celsius with normal fat content. What is the most probable explanation?

  1. Water has been added to the milk Correct answer.
  2. The milk has been homogenised
  3. The milk has been partially skimmed
  4. The milk is from a Jersey cow

Explanation

Removing fat raises milk density, so low density with normal fat points to dilution with water, which lowers the density of the serum. The freezing point test would confirm added water. Breed and homogenisation do not explain a density this low at normal fat.

Question 15Milk: composition, physical and chemical properties

Which protein fraction of milk is most heat-labile and denatures readily on pasteurisation?

  1. Beta-casein
  2. Alpha-casein
  3. Beta-lactoglobulin Correct answer.
  4. Kappa-casein

Explanation

Beta-lactoglobulin is a compact whey protein that unfolds and denatures at pasteurisation temperatures, exposing sulphydryl groups responsible for the cooked flavour. Caseins are remarkably heat-stable and withstand boiling without coagulating. Lactalbumin also denatures but is generally less affected than beta-lactoglobulin.

Question 16Milk: composition, physical and chemical properties

The buffering capacity of milk over the pH range 5 to 6 is mainly due to which constituents?

  1. Lactose and milk fat
  2. Dissolved oxygen and nitrogen
  3. Ascorbic acid and riboflavin
  4. Casein, phosphate and citrate Correct answer.

Explanation

Milk resists pH change because its casein phosphates together with inorganic phosphate and citrate act as buffers. These groups release or take up hydrogen ions as acid is formed or added. Fat and lactose contribute little to buffering in this range.

Question 17Milk: composition, physical and chemical properties

Which fatty acid is characteristic of ruminant milk fat and often used as a marker of butterfat?

  1. Linoleic acid
  2. Butyric acid Correct answer.
  3. Oleic acid
  4. Palmitic acid

Explanation

Ruminant milk fat contains short-chain fatty acids, and butyric acid (C4) is virtually unique to it among common food fats. Its presence is used to detect butterfat and it is released on lipolysis, giving rancid off-flavours. Oleic, linoleic and palmitic acids occur widely in many fats.

Question 18Milk: composition, physical and chemical properties

Why is the refractive index of milk serum useful in dairy analysis?

  1. It measures the calcium content directly
  2. It measures the bacterial count
  3. It quantifies the fat globule size
  4. It indicates the concentration of dissolved solids and detects added water Correct answer.

Explanation

After fat and casein are removed, the refractive index of the clear serum depends on dissolved lactose and salts. A low reading suggests dilution with water, and the butyrometer refractometer method uses this relation. Fat globule size and bacterial numbers do not affect the serum refractive index.

Question 19Milk: composition, physical and chemical properties

Which change in milk composition is expected when a cow suffers from mastitis?

  1. Increased lactose and increased potassium
  2. Increased fat and increased casein
  3. Increased somatic cells, increased chloride and decreased lactose Correct answer.
  4. Decreased chloride, decreased sodium and increased lactose

Explanation

Mastitis damages the udder's secretory tissue and increases the permeability of the blood-milk barrier. The result is a rise in somatic cells, sodium and chloride, with a fall in lactose and potassium. The chloride content rises enough to make the milk salty.

Question 20Milk: composition, physical and chemical properties

Colostrum differs from normal milk most markedly in which respect?

  1. It contains far more lactose and less protein
  2. It contains much more immunoglobulin and total protein Correct answer.
  3. It is completely free of minerals
  4. It has a much higher fat content than normal milk

Explanation

Colostrum, the first secretion after calving, is rich in immunoglobulins, giving total protein levels several times those of normal milk. It also contains more minerals and less lactose, and it is yellow and viscous. It is unsuitable for normal dairy processing because heat coagulates its proteins.

Question 21Milk: composition, physical and chemical properties

Two milk samples have the same fat percentage, but sample A has a higher solids-not-fat content. What can be inferred?

  1. Sample A has a higher total solids content Correct answer.
  2. Sample A has a higher freezing point
  3. Sample A contains more added water
  4. Sample A has a lower total solids content

Explanation

Total solids equal fat plus solids-not-fat, so with equal fat the sample with more solids-not-fat must have more total solids. Higher solids-not-fat also slightly raises density and lowers the freezing point. Added water would reduce, not increase, solids-not-fat.

Question 22Milk: composition, physical and chemical properties

During the manufacture of paneer, citric acid is added to hot milk. Which chemical event is chiefly responsible for the curd formation?

  1. Hydrolysis of lactose into glucose and galactose
  2. Oxidation of milk fat by citric acid
  3. Denaturation of beta-lactoglobulin into a gel network
  4. Neutralisation of casein micelles and loss of electrostatic repulsion at pH near 4.6 Correct answer.

Explanation

Acidification lowers pH toward the isoelectric point of casein, neutralising the negative charge on the micelles and allowing calcium phosphate to dissolve. The micelles then aggregate into a curd that traps fat and serum. Heat accelerates this aggregation and improves yield.

Question 23Milk: composition, physical and chemical properties

A milk sample gives a freezing point of minus 0.45 degrees Celsius. What is the most reasonable conclusion?

  1. The milk is from a buffalo
  2. The milk has been homogenised
  3. The milk has an abnormally high lactose content
  4. The milk has been diluted with water Correct answer.

Explanation

Normal milk freezes near minus 0.53 degrees Celsius, and dilution with water reduces the depression of freezing point toward zero. A value of minus 0.45 is significantly less negative and indicates added water. Buffalo milk normally has a slightly greater depression because of its higher solids.

Question 24Milk: composition, physical and chemical properties

Which combination best explains why milk is opaque white rather than transparent?

  1. Presence of chlorophyll in the serum
  2. Light scattering by casein micelles and fat globules Correct answer.
  3. Dissolved lactose absorbs all visible light
  4. High concentration of dissolved gases

Explanation

Casein micelles, roughly 50 to 300 nm in diameter, and fat globules scatter visible light of all wavelengths, producing the white opaque appearance. Skim milk is slightly bluish because fat scattering is removed and casein scatters shorter wavelengths more. Absorption by lactose or gases plays no role.

Question 25Milk: composition, physical and chemical properties

Which statement about the effect of heat on milk salts is correct?

  1. Heating converts all calcium into free ionic calcium
  2. Heating removes calcium as insoluble carbonate
  3. Heating shifts soluble calcium phosphate into the colloidal micellar form Correct answer.
  4. Heating has no effect on the distribution of calcium and phosphate

Explanation

On heating, the solubility of calcium phosphate falls and part of the soluble salt precipitates onto casein micelles, increasing colloidal calcium phosphate. This shift explains the slight decrease in ionic calcium and the altered rennet coagulation of heated milk. The change is reversible on cooling but is not a removal of calcium.

Question 26Milk: composition, physical and chemical properties

Lactose is the principal carbohydrate of milk. Chemically, lactose belongs to which class of compounds?

  1. A monosaccharide identical to glucose
  2. A disaccharide made of glucose and galactose Correct answer.
  3. A polysaccharide made of repeated glucose units
  4. A trisaccharide made of glucose, fructose and galactose

Explanation

Lactose is a disaccharide formed by a glycosidic bond between one glucose unit and one galactose unit, giving it the formula C12H22O11. On hydrolysis, or in the intestine via the enzyme lactase, it splits into these two monosaccharides. This is why lactose is a reducing sugar and why its sweetness is far lower than that of sucrose.

Question 27Milk: composition, physical and chemical properties

A dairy technician measures the specific gravity of a milk sample and finds it lower than normal while the fat content is normal. Which interpretation of this result is most appropriate?

  1. The sample is definitely from a cow in late lactation and needs no further testing
  2. The low specific gravity proves the milk is richer in protein than usual
  3. The sample may have been watered down, so a freezing-point test should be done to confirm Correct answer.
  4. The result is impossible because specific gravity does not depend on composition

Explanation

Adding water lowers the density of milk because water is less dense than the solids-not-fat fraction, so a low specific gravity with normal fat suggests dilution. Because fat itself is light, a low reading could also reflect high fat, so the result must be confirmed with a freezing-point or solids-not-fat determination. Judging adulteration from specific gravity alone is unreliable.

Question 28Milk: composition, physical and chemical properties

Fresh milk is described as a buffer system. Which pair of constituents is chiefly responsible for its resistance to pH change in the freshly drawn range?

  1. Lactic acid and free fatty acids
  2. Ascorbic acid and riboflavin
  3. Lactose and milk fat
  4. Phosphates and citrate together with the milk proteins Correct answer.

Explanation

Milk contains colloidal calcium phosphate, soluble phosphate and citrate salts, and amphoteric proteins such as casein, all of which can absorb or release hydrogen ions. Together these systems hold the pH of fresh milk near 6.6 to 6.7 even when small amounts of acid are formed. This buffering is why a noticeable drop in pH requires considerable lactic acid production.

Question 29Milk: composition, physical and chemical properties

Which statement correctly describes the state of milk fat in freshly drawn, unhomogenised cow milk at body temperature?

  1. It is present as solid crystals dispersed without any membrane
  2. It is completely dissolved as a true solution in the aqueous phase
  3. It is present as an oil-in-water emulsion of globules stabilised by a milk fat globule membrane Correct answer.
  4. It is present as a water-in-oil emulsion stabilised mainly by casein micelles

Explanation

Milk fat is dispersed as microscopic globules in the aqueous phase, so the continuous phase is water and the dispersed phase is fat, making it an oil-in-water emulsion. Each globule is coated with a membrane of phospholipids and proteins that prevents the globules from coalescing. Casein micelles stabilise the aqueous phase but are not the emulsifier of the fat.

Question 30Milk: composition, physical and chemical properties

A sample of milk is analysed and found to have a freezing point of about minus 0.540 degrees Celsius, with normal fat and normal total solids. Which conclusion is most defensible?

  1. The milk has been adulterated with about 10 per cent water
  2. The value is within the normal range for cow milk, so no added water is indicated Correct answer.
  3. The milk has been overheated during pasteurisation
  4. The milk contains added sugar or another soluble solid

Explanation

The freezing point of genuine cow milk lies close to minus 0.53 to minus 0.55 degrees Celsius, set mainly by the dissolved lactose and salts. A reading near minus 0.540 degrees Celsius therefore falls inside the accepted range and does not indicate dilution. Adding water would raise the freezing point towards zero, while adding sugar or other solutes would depress it further.

Question 31Milk production, collection and quality testing

Which test is used to determine the fat content of milk by the Gerber method?

  1. Measurement of specific gravity with a lactometer
  2. Butyrometer reading after sulphuric acid digestion and centrifugation Correct answer.
  3. Determination of chloride content by silver nitrate titration
  4. Titration with N/10 sodium hydroxide using phenolphthalein

Explanation

The Gerber method digests milk protein with concentrated sulphuric acid, releases fat with amyl alcohol, and separates it by centrifugation; the fat column is then read directly on the butyrometer scale as a percentage. It is the standard routine fat test in Indian milk collection centres.

Question 32Milk production, collection and quality testing

A lactometer reading of 26 at 27 degrees Celsius with milk temperature correction indicates which property of milk?

  1. Refractive index
  2. Specific gravity Correct answer.
  3. Titratable acidity
  4. Freezing point

Explanation

The lactometer is a hydrometer calibrated to float in milk, and its reading corresponds to the specific gravity of the sample. The reading is corrected for temperature because specific gravity changes with warmth.

Question 33Milk production, collection and quality testing

In the standard Gerber method, which reagent is added to the butyrometer along with milk and amyl alcohol?

  1. Saturated sodium chloride solution
  2. Neutral buffered formalin
  3. Concentrated sulphuric acid of about 90 per cent strength Correct answer.
  4. Ethyl alcohol of 95 per cent strength

Explanation

Concentrated sulphuric acid (commercial strength, about 90 per cent) digests the casein and dissolves the non-fat solids so that fat can separate cleanly. Amyl alcohol is added to help the fat column remain clear and well defined.

Question 34Milk production, collection and quality testing

Milk is tested for titratable acidity using phenolphthalein indicator and N/10 sodium hydroxide. A fresh mixed milk sample gives a reading of 0.14 per cent lactic acid. What does this indicate?

  1. The milk has been heavily soured by bacteria
  2. The milk has been adulterated with water
  3. The milk contains added starch
  4. The milk is normal and freshly drawn Correct answer.

Explanation

Fresh normal cow or buffalo milk typically shows titratable acidity of about 0.10 to 0.16 per cent lactic acid, so a value of 0.14 per cent falls in the normal range. Higher values suggest bacterial souring of lactose to lactic acid.

Question 35Milk production, collection and quality testing

Which reagent is used to detect added starch in milk?

  1. Ammonium molybdate solution
  2. Fehling's solution
  3. Silver nitrate solution
  4. Iodine solution Correct answer.

Explanation

Iodine reacts with starch to give a characteristic blue colour, so a blue development after adding iodine indicates starch adulteration. Pure milk gives only the yellowish brown colour of the iodine itself.

Question 36Milk production, collection and quality testing

A milk sample is tested for added cane sugar. Which test is appropriate?

  1. Gerber butyrometer test
  2. Resorcinol test after removal of protein and fat Correct answer.
  3. Alizarin test for carbonate
  4. Bromothymol blue dye reduction test

Explanation

Cane sugar (sucrose) is detected by a resorcinol-hydrochloric acid colour reaction carried out on a clarified filtrate after proteins and fat are removed. Sucrose gives a characteristic cherry red colour.

Question 37Milk production, collection and quality testing

Which test is used to detect the presence of added water in milk?

  1. Freezing point depression using a cryoscope Correct answer.
  2. Gerber fat reading
  3. Alizarin colour reaction
  4. Methylene blue reduction time

Explanation

Pure milk has a fairly constant freezing point near minus 0.55 degrees Celsius, and added water raises it towards zero. A cryoscope measures this freezing point precisely, making it the reference test for water adulteration.

Question 38Milk production, collection and quality testing

Which dye is used as the redox indicator in the methylene blue reduction test of milk?

  1. Phenolphthalein
  2. Methylene blue chloride Correct answer.
  3. Safranin
  4. Crystal violet

Explanation

Methylene blue is a redox dye that is decolourised when the oxygen in milk is consumed by the metabolic activity of bacteria. The time taken for decolourisation is inversely related to the bacterial load.

Question 39Milk production, collection and quality testing

In the methylene blue reduction test, a sample that decolourises within 30 minutes indicates what about the milk?

  1. Normal acceptable market quality
  2. Presence of added water
  3. Very poor quality with a high bacterial load Correct answer.
  4. Excellent quality with very few bacteria

Explanation

Rapid decolourisation means the bacteria present have consumed dissolved oxygen quickly, indicating a very high bacterial count and poor keeping quality. Longer reduction times correspond to better bacteriological quality.

Question 40Milk production, collection and quality testing

Which test is used to detect the presence of coliform bacteria in milk?

  1. Alizarin test
  2. MacConkey broth fermentation with gas production Correct answer.
  3. Gerber fat estimation
  4. Cryoscopic freezing point test

Explanation

Coliforms ferment lactose in MacConkey broth with gas production, which is detected in a Durham tube. Gas formation confirms presumptive coliform contamination, which signals poor hygiene.

Question 41Milk production, collection and quality testing

Which preservative is commonly added to milk samples sent to a laboratory for chemical analysis when the sample cannot be tested immediately?

  1. Sodium chloride
  2. Potassium dichromate Correct answer.
  3. Calcium hydroxide
  4. Sodium bicarbonate

Explanation

Potassium dichromate is added at a small concentration to preserve milk samples for chemical analysis by inhibiting bacterial growth without significantly altering composition. It is not used for samples intended for bacteriological testing.

Question 42Milk production, collection and quality testing

A milk sample gives a positive alizarin test. What adulterant does this indicate?

  1. Added starch
  2. Added cane sugar
  3. Added carbonate or bicarbonate neutraliser Correct answer.
  4. Added water

Explanation

The alizarin test turns yellow or violet in the presence of added alkaline substances such as sodium carbonate or bicarbonate, which are added to mask developed acidity. It is therefore a test for neutralisers.

Question 43Milk production, collection and quality testing

What is the purpose of the platform test carried out on milk received at a dairy?

  1. To determine the exact fat and SNF for payment
  2. To confirm the breed of the animal
  3. To measure the shelf life of processed milk
  4. To make a rapid decision on acceptance or rejection at the receiving dock Correct answer.

Explanation

Platform tests are quick, simple checks performed at reception to decide whether milk should be accepted or rejected before it enters processing. Examples include organoleptic examination, clot-on-boiling, acidity, and specific gravity.

Question 44Milk production, collection and quality testing

In the clot-on-boiling test, milk that shows curdling when boiled indicates which condition?

  1. Presence of coliform bacteria
  2. Excess fat content
  3. Developed acidity approaching the isoelectric point of casein Correct answer.
  4. Presence of added water

Explanation

When acidity rises, casein approaches its isoelectric point and coagulates on heating, producing a clot on boiling. Such milk is unstable and unsuitable for processing.

Question 45Milk production, collection and quality testing

Which instrument is used to measure the specific gravity of milk in a collection centre?

  1. Lactometer Correct answer.
  2. Butyrometer
  3. Cryoscope
  4. Colorimeter

Explanation

A lactometer is a hydrometer calibrated for milk that floats at a depth corresponding to specific gravity. The reading is corrected for temperature to give the true value.

Question 46Milk production, collection and quality testing

Milk is collected from a village society in a bulk milk cooler. Which practice best preserves its bacteriological quality before transport to the dairy?

  1. Cooling the milk rapidly to about 4 degrees Celsius and holding it there Correct answer.
  2. Adding water to reduce the fat concentration
  3. Storing the milk in direct sunlight to keep it warm
  4. Leaving the milk uncovered for aeration

Explanation

Rapid cooling to around 4 degrees Celsius slows bacterial multiplication and preserves quality during storage and transport. This is the basis of the bulk milk cooler system used in village collection.

Question 47Milk production, collection and quality testing

Which of the following is a correct sequence of operations in a village milk collection centre?

  1. Churning, butter making, ghee making, and dispatch
  2. Receiving, weighing, sampling for tests, recording, and dispatch to the dairy Correct answer.
  3. Pasteurising, homogenising, packing, and dispatch
  4. Standardising, evaporating, drying, and dispatch

Explanation

A collection centre receives raw milk, weighs it, draws a representative sample for platform tests, records quantity and quality, and then dispatches the milk to the dairy for processing. Processing operations occur at the dairy, not at the village centre.

Question 48Milk production, collection and quality testing

A sample of milk has a specific gravity of 1.020 and a fat content of 6.0 per cent. Which conclusion is most reasonable?

  1. The sample is definitely cow milk
  2. The sample is definitely adulterated with water
  3. The sample contains added starch
  4. The sample is likely buffalo milk and within the normal range for that species Correct answer.

Explanation

Buffalo milk normally has higher fat (about 6 to 7 per cent) and specific gravity around 1.030 to 1.032, though a reading of 1.020 with high fat is plausible given the inverse relationship between fat and specific gravity. The combination is consistent with a buffalo milk sample rather than proof of adulteration.

Question 49Milk production, collection and quality testing

Which of the following correctly describes the relationship between fat content and specific gravity in normal milk?

  1. Higher fat raises specific gravity because fat is denser than water
  2. Fat content has no effect on specific gravity
  3. Higher fat generally lowers specific gravity because fat is less dense than the aqueous phase Correct answer.
  4. Higher fat raises specific gravity only in buffalo milk

Explanation

Milk fat is less dense than the aqueous portion of milk, so an increase in fat tends to lower the specific gravity of the sample. This is why species and fat level must be considered when interpreting lactometer readings.

Question 50Milk production, collection and quality testing

Which of the following is the correct procedure for drawing a representative sample from a bulk milk tank?

  1. Skim the top layer and sample only that portion
  2. Draw the sample from the bottom without mixing
  3. Take the sample from the foam on the surface
  4. Thoroughly mix the milk and draw the sample from the well-mixed bulk Correct answer.

Explanation

Milk separates on standing because fat rises, so the bulk must be mixed thoroughly before sampling to obtain a representative portion. Sampling without mixing gives biased fat results.