W. A. (William Alonzo) Stocking.

Manual of milk products online

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I



MANUALOF
[ILK PRODUCTS



. '::



MANUAL OF MILK PRODUCTS



TTbe IRural /IDanuals

EDITED BY L. H. BAILEY

&

MANUAL OF GARDENING Bailey
MANUAL OF FARM ANIMALS Harper
FARM AND GARDEN RULE-BOOK Bailey
THE PRUNING MANUAL Bailey
MANUAL OF FRUIT INSECTS Slingerland and Crosby
MANUAL OF WEEDS Georgia
MANUAL OF FRUIT DISEASES Hesler and Whetzel
MANUAL OF MILK PRODUCTS Stocking
MANUAL OF HOME-MAKING In preparation
MANUAL OF CULTIVATED PLANTS In preparation



MANUAL

OF

MILK PRODUCTS



BY



WILLIAM A. STOCKING

PROFESSOR OF DAIRY INDUSTRY AT CORNELL
UNIVERSITY



THE MACMILLAN COMPANY
1917

All rights reserved









COPYBIGHT, 1917,

BY THE MACMILLAN COMPANY.



Set up and electrotyped. Published August, 1917.



,-;".- . -,
-.; - * . ; *

. * - ..'..:. .;



Notfajonti

J. S. Gushing Co. Berwick & Smith Co.
Norwood, Mass., U.S.A.



PREFACE

THE annual value of dairy products in the United States is
more than six hundred million dollars. The handling of these
products makes an industry of great commercial and economic
importance. The time is rapidly passing when people regard
milk, butter, cheese, and ice cream as luxuries to be used chiefly
to please the taste. Rather, they are now used because they
furnish valuable food nutrients in desirable form. As the prob-
lem of feeding the cities becomes more acute and the food
value of dairy products is more generally recognized, they will
form a more important item in the human diet. The methods
by which these products are handled influence decidedly their
food value. It is, therefore, important that, in the handling of
these products, the best practices should be employed. During
recent years much has been added to our knowledge in this field
and much has been written, but it is widely scattered through
agricultural literature and is not easily accessible. This
"Manual" has been prepared for the purpose of bringing to-
gether the work of the best authors into such form as to meet
the needs of busy persons, both students and men in commercial
work. The book is made up largely of quotations, credit being
given in each case. No claim is made to originality, my task
being rather that of selection and arrangement. If the book
meets a need, an effort will be made to keep it up to date.

W. A. STOCKING.

ITHACA, N. Y., March, 1917.



3CC664



CONTENTS

CHAPTER I

MILK SECRETION 1-14

The purpose of milk secretion 1

Physiology of the mammary gland .... 2

The elaboration of milk in the animal organism . . 4

Early theories 4

Present theories ....... 7

Rate of activity in mammary gland .... 9

Factors which affect milk secretion . 10



CHAPTER II

THE CHEMICAL COMPOSITION OF MILK . . . . 15-39

Variation in normal cow's milk 19

The fats of milk 20

The composition of milk-fat 20

The non-volatile fats 22

The volatile fats 22

The serum of milk 23

The proteids or albuminoids .... 23

Casein 24

Albumin or lact-albumin .... 24

Lactoglobulin 24

Galactin 24

Fibrin 25

Milk-sugar 27

Citric acid 28

The mineral constituents or ash 28

Other constituents of milk 29

Condition of casein and salts in milk ... 29

Properties and composition of milk-serum . 31
Properties and composition of that part of milk in

suspension or colloidal solution . . 34
vii



Viii CONTENTS

PAGES

Appearance 34

Behavior with water 34

Reaction ....... 35

Relation of inorganic constituents to casein in

milk 35

Colostrum . . 37

Acidity of milk 38



CHAPTER III

FACTORS THAT AFFECT THE COMPOSITION OF MILK . . 41-68

Factors that affect the water-content of cow's milk . 41

Amount of variation 41

The influence of breed ....'.. 41

The influence of lactation 42

Factors that influence percentage of fat and solids in

milk 43

Influence of breed 43

Influence of individuality of cow .... 44

Influence of age of cow on fat-content of milk . 45

Influence of stage of lactation on fat-content of milk 46

Variation from day to day in herd milk . . 48

Variation from day to day in individual cow . 48
Variation of fat-content in different portions of milk

drawn from the udder .... 49
Composition of milk from different quarters of

udder .... 50
Variation of time between milkings in relation to

fat-content of milk ... . . 51
Influence of methods of milking and environment

on composition of milk . . . 52

Influence of drouth on composition of milk . . 53

Effect of food on percentage of fat in milk . 54

Influence of palm-nut meal on percentage of fat . 57

Effect of under- and over-feeding ... 59
Influence of fatness of cow on percentage of fat in

milk . 62

Effect of period of heat 66

Acidity of milk affected by silage .... 67



CONTENTS ix



CHAPTER IV

PAGES

PHYSICAL PROPERTIES OF MILK 69-101

Form of fat globules 69

Size and number of fat globules 70

Influence of breed 70

Influence of age of cows on number and size of fat

globules 72

Influence of period of lactation on size of fat globules 73

Specific gravity of milk 73

Odor of milk 74

The yellow color of milk and milk-fat .... 75

Source of the yellow color of milk-fat ... 77

Relation between color of milk-fat and breed of cow 78

The pigments of the fat from colostrum milk . . 82

The yellow pigment of milk whey .... 85

Factors influencing the color of milk whey . . 85

Influence of breed on the color of milk whey . 87
Influence of the stage of lactation on the color of the

whey 88

Influence of the age of the animal on the color of

the milk whey 88

Influence of the volume of milk production on the

color of the milk whey .... 88

Influence of feed on the color of the milk whey . 89

Viscosity or consistency of milk 91

Effect of physical agents 92

Heat 92

Centrifugal force 94

Effect of chemical agents 95

Acids 95

Alkalies 95

Conclusions ........* 96

The specific heat of milk and milk derivatives . . 96

Specific heat of whole milk 98

Specific heat of whey .... 99

Specific heat of skim-milk ....*. 99

Specific heat of cream .... 99

Specific heat of butter 100

Specific heat of butter-fat 100



CONTENTS

PAGES

Freezing point of milk 101

Electrical resistance and conductivity . . . 101

Refractive index of milk 101



CHAPTER V

THE TESTING OF MILK AND CKEAM .... 102-148

Apparatus and chemicals 103

Accuracy of the glassware . . . . . . 105

Reagents used in calibrating .... 108

How to use the burette 108

Testing milk for butter-fat by the Babcock method . 109

Sampling the milk 109

Single samples of milk 109

Composite samples of milk . . . . 110

Jars for composite sampling . . . . 110

Taking composite samples . . . . Ill

Objection to composites . . . . 112

Care of the milk sample 112

Preparation of sample for the test . . . 113

Milk test bottles 114

Measuring the milk into the test bottle . . 114

Adding acid . . . . . . . . 115

Whirling and adding water 116

Reading the test . 118

Abnormal appearance of the fat column . . 118

Cream testing . 119

Sampling the cream 119

Care of the cream on the farm . . . 119

Sampling by the cream hauler . . 120

Composite samples of cream . . . 122

Care of the cream sample .... 122

Preparation of the cream sample for the test . 122

Weighing the cream into the test bottle . . 123

Cream test bottles . ' . .-. . . . . 124

Adding the acid ....... 124

Whirling and adding water 125

Reading the test . 126

Purpose and use of glymol 126



CONTENTS xi

PAGES

Coloring glymol 128

Abnormal appearance of the fat column . . 128

Testing skim-milk and buttermilk .... 129

Testing frozen milk 130

Testing sour milk 132

Testing churned milk 132

Acidity of milk 132

Tests for solids not fat and total solids in milk . . 136

Methods of determining viscosity or consistency . . 143

Milk sediment test 144

Test for the detection of formaldehyde . . . 145

Test for boracic acid 145

Test for salicylic acid ....... 146

Test for benzoic acid 146

Detection of heated milk 147

Arnold's guaiac method 147

Microscopic test for heated milk .... 148



CHAPTER VI

MARKET MILK 149-205

Importance of clean milk to the consumer . . . 152

Importance of clean milk to the producer . . . 152

Sources of milk contamination 153

How to produce clean milk 153

The cows and their care 153

The stable 155

The milk-house 157

Utensils 158

Milking 160

Scoring methods of production ' 161

Treatment after milking 163

Straining 163

Aeration ... 164

Clarification of milk 165

Cooling of milk 165

Methods of cooling milk 167

Refrigerating material ...... 168

Effect of stirring milk during cooling in tanks . 168



xii CONTENTS

PAGES

Transportation of milk 170

Treatment in the city 172

Pasteurization of milk and cream .... 172
Methods of pasteurization ..... 174
Advantages of low- temperature pasteurization . 176
Temperatures and methods most suitable for pas-
teurization 177

Handling pasteurized milk 179

Cost of pasteurizing milk ... . 180

Converting pounds to quarts and quarts to pounds . 180

Standardizing milk and cream . . 181

Delivery in town and city ' 183

The cost of clean milk 184

Grading of milk and cream 185

Score cards for city milk plants 192

Score card for milk 194

Score card for cream 197

The care of milk in the home 199

Receiving the milk . . . 200

Handling and keeping milk 200

The refrigerator 201

Cleaning empty bottles and utensils . . 202

Contagious disease 202

Pasteurization of milk in the home . . . 203

CHAPTER VII

CERTIFIED MILK 206-223

Obstacles to the profitable production of certified milk 209
The future of certified milk . 211
Methods and standards for the production and distribu-
tion of certified milk .... 212

Hygiene of the dairy 212

Transportation ... . 216
Veterinary supervision of the herd . 217
Bacteriological standards .... 218
Chemical standards and methods . 219
Methods and regulations for the medical examina-
tion of employees; their health and per-
sonal hygiene 221



CONTENTS Xlll



CHAPTER VIII

PAGES

BUTTER-MAKING 224-288

Creaming 225

Methods of creaming 227

Water dilution method 228

Centrifugal creaming 229

Development of the centrifugal separator . . 229

Conditions affecting separation . . . . 231

Quality of cream for butter-making .... 235

Directions for care of cream on the farm . . 236

Grading of cream ....... 237

The ripening of cream 238

Amount of starter to use , 246

Quality of starter 246

Temperature for ripening cream .... 247

Amount of acid to develop 248

Pasteurization of cream for butter-making . . . 248

Churning 250

Richness of the cream 250

Temperature of cream 251

The ripeness of the cream 251

The amount of cream in the churn . . . 252

The speed of the churn 252

The quality of the fat globules .... 253

When to stop the churn . , . . . 253

Difficult churning 254

Washing the butter 254

Purpose of washing 254

Temperature of the water 255

Quality of wash water 255

Salting the butter 255

Moisture-content of the butter 256

The factors under the control of the butter-maker 257

Factors not under the control of the .butter-maker 258

Working the butter ....... 260

Printing and packing the butter 261

Butter grades and scores 262

Butter rules of the New York Mercantile Exchange . 263

Butter defects and how to correct them 267



xiv CONTENTS

PAGES

Testing butter for fat 273

Butter-moisture tests 274

Cornell butter-moisture test 274

Taking the sample 276

Preparing the sample for testing . . . 276

Operation of the test 278

Test for salt in butter 279

Apparatus 279

Reagents 280

Making the test 280

Whey butter 280

Renovated butter] 281

Method of working some creamery problems . . 283
Computing the percentage of fat in a vat of cream

after starter is added .... 283

Value of salted versus unsalted butter . . . 284
Computing the amount of cream necessary to make

a cream-gathering route profitable . . 284

Creamery dividends 286

Computing the rate in a cooperative creamery . 286

Computing the average price of butter for one year 288

CHAPTER IX

CHEDDAR CHEESE 289-349

Composition of cheese 290

Quality of milk for cheese-making .... 290

The Wisconsin curd test 292

Relation between the composition of milk and the yield

and composition of cheese . . . 293

Method of making cheddar cheese .... 300

Publow acid test 300

Directions for using the acidimeter . . 302

Amount of acid to be developed at each stage . 303

Rennet tests 304

Proper degree of ripeness ..... 305

Coloring the milk 306

Adding the rennet 306

Pepsin . , . . . . . . 306

Manipulating the curd . . . ... 307



CONTENTS XV

PAGES

Method of cutting the curd 308

Heating the curd . 309

Cheddaring the curd 310

Milling the curd 310

Salting the curd . 312

Pressing the curd 312

Curing the cheese 314

Testing cheese for fat 316

Cheese-moisture test 317

Test for casein in milk 318

Measuring the casein 320

Modifications of the cheddar process .... 321

Skimmed-milk cheese 321

Soaked-curd cheese 322

Cheese from pasteurized milk .... 323

Sage cheese 327

Defects in American cheddar cheese .... 327

Quality and judging of cheese 340

Cheese score card 341

Cheese rules of the New York Mercantile Exchange . 342

Cheese problems 346

Estimating cheese yield of milk, using fat-content

as a basis of calculation . . . 346

Value of fat usually lost in whey .... 347
Calculating the rate of payment on the fat basis

in a cooperative cheese factory . . 348



CHAPTER X

FANCY CHEESES 350-390

Limburger cheese 350

Emmental or Domestic Swiss ..... 351

Stilton cheese 355

Gorgonzola 356

Roquefort . . 357

The manufacture of Edam cheese .... 359

Kind of milk used 359

Treatment of milk before adding rennet . . 360

Addition of rennet to milk 360

Cutting the curd 360



CONTENTS

Treatment of curd after cutting ....
Filling molds, pressing and dressing cheese .

Salting and curing

Curing room

Utensils employed in making Edam cheese .

Qualities of Edam cheese

Loss of milk-solids in manufacture of Edam cheese
Amount of fat lost and recovered in the manufac-
ture of Edam cheese ....
Influence of composition of milk on yield of cheese
Yield of green cheese from one hundred pounds of

milk

Amount of water retained in cheese
Comparison of Edam and American cheddar cheese
with reference to profit in manufacture .
The manufacture of Gouda cheese ....
Treatment of milk before adding rennet

Addition of rennet to milk

Cutting the curd

Treatment of curd after cutting ....
Pressing and dressing cheese ....

Salting and curing

Utensils employed in making Gouda cheese
Loss of fat in the manufacture of Gouda cheese
Loss of casein and albumen in the manufacture of

Gouda cheese

Yield in the manufacture of Gouda cheese
Directions for making the Camembert type of cheese .
The cheese-making plant .....
Equipment of the making room ....

Vats

Apparatus for determining ripeness

Curd knife and dipper .....

Draining table

Hoops, or forms

Boards

Mats

Cane bottoms

Equipment of ripening rooms . . .
Construction and condition of the rooms



CONTENTS xvii

PAGES

Making room 374

First ripening room 375

Second ripening room 375

Protection against insects- .... 376

The making, of the cheese 376

The milk 376

Ripening the milk 376

The starter 377

Adding the rennet ...... 378

Cutting the curd 378

Dipping the curd into the forms . . . 379

Inoculation and turning . 380

Salting 382

Making cheese from uncut curd . . . 382

The use of the low forms .... 383

Ripening the cheese 383

Factory methods 385

Various defects of cheese 386

Gassy curd . . 386

Yeast 386

Molds . . . ... . . 387

Dry cheese 387

Wet cheese 387

Mites 387

Skippers 387

Estimated equipment for a factory . . . 388

Brie cheese 389

CHAPTER XI

FARM DAIRYING . . 391-451

Testing milk on the farm 392

Sampling the milk ...... 392

Testing the milk 393

Testing cream on the farm 393

Method of selling milk ...... 394

Making butter on the farm . . . ' . . . 396

Care of milk and utensils 396

Method of creaming 397

Selection of the separator 398

Variation in percentage of fat from hand-separator 399



xvill CONTENTS

PAGES

Care of the cream 401

The ripening of cream 402

Propagation of starter for butter-making . . 403

Methods of determining the ripeness of cream . 406

Coloring the butter . . . . ' . . 407

Churning 407

The object of churning 410

Washing the butter 411

Salting the butter 412

Working the butter 413

Printing and packing butter .... 414

Marketing the butter 415

Butter score card . . . . . . 416

Holding butter for winter use 417

Cheese-making on the farm 418

Methods for making cheddar cheese on the farm . 419

Coagulate milk with rennet .... 419

Cutting the curd 420

Heating the curd . ... 421

Preparing the cheese for the press . 422

Pressing the cheese ..... 423

Curing the cheese ... . 424

Methods of making some of the soft cheese . . 425

Pasteurization 425

Pot cheese .... 427

Method of manufacture .... 427

Yield

Qualities of pot cheese

Baker's cheese

Method of manufacture .... 429

Yield .... ...

Qualities of baker's cheese ....

Cottage cheese

Method of manufacture . . . /

Composition . . ,
Marketing ...
Qualities of cottage cheese ....
Defects in pot, baker's, and cottage cheese .

Neufchatel cheese .... 434

Method of manufacture .... 435



CONTENTS XIX

PAGES

Yield . .... 438

Qualities of Neufchatel cheese . . . 438

Cream cheese 438

Method of manufacture using Neufchatel curd 439
Method of manufacture using 10 per cent

cream 439

Yield 439

Marketing 440

Qualities of cream cheese .... 440

Pimento cheese 440

Method of manufacture .... 440

Yield . 441

Marketing 441

Qualities of pimento cheese .... 441

Club cheese 441

Method of manufacture .... 442

Marketing 442

Summary 442

Problems in dairy arithmetic . . 443

Market milk and cream ... . 443
Converting pounds to quarts and quarts to

pounds 443

Computing the pounds of fat in dairy products 444
Computing percentage of fat, pounds of prod-
uct, or pounds of fat, having any two of

these quantities given . . . 445

Standardizing milk and cream . . . 445
Computing the average percentage of fat in

the milk of a herd 447

Computing fat recovered during separation . 448
Comparative value of different methods for

disposing of milk and its products . . 448

Butter problems 450

Computing overrun in butter . . . 450

Butter yield of cream 451

CHAPTER XII

CONDENSED AND POWDERED MILK 452-477

Extent of the industry 453

Conditions essential for a milk condensery . . , 455



XX CONTENTS

PAGES

Definitions and standards 459

Process of manufacture for unsweetened condensed milk 460

Effect of concentration upon acidity . . . 462

Sterilization and keeping quality .... 465

Composition 466

Testing unsweetened condensed milk . . . 466

Testing for fat 466

Testing for solids 467

Sweetened condensed milk 468

Composition ....... 469

Uses of condensed milk 469

Powdered milk . . . . . . . . 469

Process of making powdered milk . . . 470

The Ekenberg process 471

Composition 472

The Merrell-Soule process .... 472

Methods of marketing 476

Definitions and standards 477



CHAPTER XIII

FERMENTED MILK 478-510

Therapeutic value of fermented milk . . . 479

Food value of fermented milk 486

The various forms of fermented milk .... 487

Cultures in tablet and capsule form . . . 487

Buttermilk 488

Making buttermilk in the home . . . 494

Kefir 495

Kumiss 502

Yogurt 504



CHAPTER XIV

ICE CREAM MAKING 511-546

Essential characteristics of ice cream .... 512

Body . . ....... 513

Aging 514



CONTENTS XXI

PAGES

Pasteurized cream 514

Fillers . 514

Texture . . . 514

Smell 516

The constituents of ice cream . . . . 519

The cream ........ 519

Flavor ........ 519

Fat-content 520

Age 521

Holding temperature 521

Keeping cream sweet 522

Acidity ' 523

Pasteurized cream 524

Homogenized cream 524

Condensed milk ....... 526

The sugar 527

The fillers 527

Starchy fillers 527

Egg fillers 528

Rennet fillers 528

The binders ....... 529

Gelatin . 529

Gum tragacanth 530

Ice cream powders . . . . . 531

Types of freezers 531

Vertical-batch-ice 532

Vertical-batch-brine 532

Horizontal-batch-brine 532

Horizontal-continuous-brine .... 532

The freezing process 533

Salt and ice . . . . . . . 534

Proportions of salt and ice .... 535

Duration 535

Speed . 537

Cream churning in the freezer .... 537

The freezing point . . *.. 538

Transferring 538

Holding 539

Re-hardening ice cream 539

Re-freezing ice cream ...... 540



Xxil CONTENTS

PAGES

Butter from ice cream ...... 540

Fat-content of different portions .... 541

Shipping 541

Modification table 542

Testing ice cream for fat 543

Ice cream score cards . . . . . . 543

CHAPTER XV

THE RELATION OF BACTERIA TO DAIRY PRODUCTS . . 547-573

Relation of bacteria to milk 547

Sources of bacterial contamination . . . 547

Interior of udder 547

Exterior of cow's body ..... 548

The dairy utensils 549

Development of bacteria in milk . . . 549

Changes in milk due to bacteria .... 551

Milk as a carrier of disease ..... 553

Pasteurization of milk 555

The quality of milk to be pasteurized . . 556

Methods of pasteurization . . . . 556

The "flash" process . . . . 557

The "holder" process .... 557

Temperatures and methods to be used . . 558

Holding and delivery of pasteurized milk . 559

Pasteurization of skim-milk and whey . . 560

Delivery of hot skim-milk . . 562

The whole milk must be sweet . . 562

Feeding value of pasteurized skim-milk . 563

Amount of water added to skim-milk by

pasteurizing with steam . . . 563

Pasteurizing buttermilk .... 564

Tests for pasteurized milk .... 565

Storch's test . . . . . 565

Potassium iodide-starch test . . . 566

Infectious mastitis . . . . . 567

Relation of bacteria to butter 568

Abnormal flavors . . . . . . 569

Disease bacteria in butter * 569

Relation of bacteria to cheese . >- . . . * 571

Disease organisms in cheese .... 572



LIST OF FIGURES

FIGUKE PAGE

1. Cross Sections of Alveoli (From Meade Smith, after Heiden-

hain) 3

2. Fat Globules in Cream, Milk, and Skim-milk ... 69

3. Relative Size of Fat Globules as Affected by Breed and

Period of Lactation ....... 72

4. Lovibond Tintometer 76

5. Device for Calibrating Test Bottles . . 106

6. Burette for Calibrating Test Bottles 107

7. Glass-stoppered Milk Sample Bottle . .110

8. Milk Sample Bottle with Metal Cap 110

9. Mason Fruit Jar for Milk Samples 110

10. McKay Milk Samplers . . . . . . .111

11. Standard Milk Test Bottle 114

12. Standard Babcock Pipette 115

13. Transferring Milk to Test Bottle . ... . .115

14. Acid Bottle 116

15. Acid Measure 116

16. Transferring Acid to Test Bottle 116

17. Mixing Acid and Milk . 116

18. Original Babcock Tester 117

19. Babcock Tester Facile (D. H. Burrell & Company) . 117

20. Babcock Tester Wizard (Creamery Package Manufac-

turing Company) 117

21. Babcock Tester International 117

22. Reading the Fat Column 118

23. Scale for Weighing Cream 120

24. Pail for Weighing Cream 120

25. Cream Stirrer and Sampler 120

26. Cream Sample Jar Screw-top 121

27. Cream Sample Tubes Cork-top 121

28. Test Bottle Short-neck 124

29. Test Bottle Long-neclj . .124

xxiii



XXIV LIST OF FIGURES



30. Water Bath (Creamery Package Manufacturing Com-

pany) 125

31. Reading the Cream Test 126

32. Dividers for Reading the Cream Test 126

33. Use of Glymol for Removing the Meniscus .... 127

34. Glymol Bottle 127

35. Skim-milk Test Bottles 129

36. Farrington Acid Test 135

37. AViscometer 143

38. Milk Sediment Tester 145

39. Constituents of Milk 150

40. Construction of Milk Pails 159

41. Fat Globules and Bacteria Relative Size .... 164

42. Chart for Pasteurization of Milk (C. E. North) . . .178

43. Wire Basket for Pasteurizing Milk 204

44. Small Top Milk Pail 211

45. De Laval Separator (De Laval Cream Separator Company) 230

46. Simplex Separator (D. H. Burrell & Company) . . . 231

47. Sharpies Separator (Sharpies Separator Company) . . 232

48. Power Starter Can (Creamery Package Manufacturing Co.) 242

49. Simplex Churn (D. H. Burrell & Company) . . . 250

50. Acme Butter Printer (Creamery Package Manufacturing

Company) . 261

51. Cornell Butter Moisture Scale 275

52. Publow Acid Test 301

53. Marschall Rennet Test (D. H. Burrell & Company) . . 305



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