eS SSSeEs STs 5 5 AES SPEER Se Se ee apes See re ease rievermrates 3 ate Ste ee ietee esas Pees Tae; pt hi = SS ae ae SSS args 332 sire aes Pa z SASHES sete ae tS Pn Pare Sees yee cero? geieststifises Ret pea wissaae it settee rae Taz e ABs tea Bstesregt ss, ~~ Fiat eSeresere sae ; sis3ehit ota COPYRIGHT DEPOSIT. , % aic5 Sts Be >see: \ . 3 ; es cs ras ORs ~ ae PT eae anaes ear Sep HUSLIA Sica NOTRE TSE SINT IRC/ SINS RLS K IE ies kia peter REO ht S. M. BABCOCK DR Inventor of the Babcock M ilk Test TESTING MILK awn ITS PRODUCTS A MANUAL FOR DAIRY -STUDENTS, CREAMERY AND CHEESE FACTORY OPERATORS, FOOD CHEMISTS, AND DAIRY FARMERS BY E. H. FARRINGTON and F. W. WOLL Professor in Charge of Dairy School Professor of Animal Nutrition UNIVERSITY OF WISCONSIN UNIVERSITY OF CALIFORNIA With Illustrations TWENTY-THIRD REVISED AND ENLARGED EDITION MADISON, WIS. MENDOTA Book COMPANY, 1916 ALL RIGHTS RESERVED CopyricuT, 1897, 1899, 1901, 1904, 1909, 1911 anp 1913. By E. H. FARRINGTON anp F. W. WOLL j ‘ CANTWELL PRINTING COMPANY MADISON, WIS. REC -6 1915 PREFACE TO FIRST EDITION. The present volume is intended for the use of dairy students. factory operators, dairymen, food chemists, and others interested in the testing or analysis of milk and its products. The subject has been largely treated in a popular manner; accuracy and clearness of statement, and systematic arrangement of the sub- ject matter have, however, been constantly kept in mind. The aim has been to make the presentation intelligible to’ students with no further training than a common-school education, but their work will naturally be greatly lightened by the aid of an able teacher. Complete directions for making tests of milk and other dairy products are given; difficulties which the beginner may meet with are considered in detail, and suggestions offered for avoid- ing them. It is expected that a factory operator or practical dairyman, by exercising common sense and ordinary care, can obtain sufficient knowledge of the subject through a study of the various chapters of this book to make tests of milk, cream, ete., even if he has had no previous experience in this line. For the benefit of advanced dairy students who are somewhat familiar with chemistry and chemical operations, Chapter XIV has been added giving detailed instructions for the complete chemical analysis of milk and other dairy products. The detee- tion of preservatives and of artificial butter or filled cheese has also been treated in this connection. As the subject of milk testing is intimately connected with the payment for the milk delivered at butter- and cheese fac- tories, and with factory dividends, a chapter has been devoted to a discussion of the various systems of factory book-keeping, and tables greatly facilitating the work of the factory secretary or bookkeeper have been prepared and are included in the Appendiz. Madison, Wis., October 3, 1897. PREFACE TO TWENTY-SECOND EDITION. Each year that passes brings some valuable contributions to our knowledge of the subjects treated in this book and a frequent re- vision of it is therefore desirable. The present edition contains descriptions of methods and apparatus that have stood the test of actual use during the past few years; the new information pub- lished since the last revision of the book has been carefully sifted, and what was deemed of sufficient importance has been incorpo- rated in such detail as the scope of the book permitted; many changes and additions suggested by the experience of the authors have also been introduced. The book has, in brief, been subjected to a renewed critical examination and careful revision. The general adoption of the book as a text or reference book in American dairy schools, as well as the favorable reception which it has been accorded by the dairy public in general, will, it is hoped, be further justified by the present revision. Acknowledgment is due to the following parties for loan of electrotypes, viz.: Cream- ery Pkg. Mfg. Co., Chicago, Ill.; Vermont Farm Machine Co., Bellows Falls, Vt.; D. H. Burrell & Co., Little Falls, N. Y.; Henry Trémner, Philadelphia, Pa.; Torsion Balance Co., New York City, and Marschall Dairy Laboratory, Madison, Wis. Madison, Wis., Oct. 1, 1913. TABLE OF CONTENTS. PAGE DE ETS I Sie eR ee 1 Chap. I. COMPOSITION OF MILK AND ITS PRODUCTS-------~- 10 eter ls) TOA MPIANG AIG 2 SS ek 23 Ghap: lil, Tee Bascock Test—MILK.__-._<_-~2__...-.- 28 A] Directions for maling the test_.... ~~. —--~-4-+.... + 29 iB, Discussion of the details of the test.-..=>~___._-_.2—- 37 Chap. IV. . THe Bascock TEstT—CrEAM___.._..-____._--- 75 Chap. V. THE BABCOCK TEST—OTHER MILK PRODUCTS_~_-~-- 90 Chap. VI. THE LACTOMETER AND ITS APPLICATION__-__---- 102 Chap. VII. TESTING THE ACIDITY OF MILK AND CREAM_---~_ 119 Pia) Gl. ESTING THE PURITY OF MILE =. os 22-2. . ys Chap. IX. TESTING MILK ON THE FARM..-..=.-..-_-.____ 142 Ghap. X. COMPOSITE SAMPLES OF- MILK__________._______ 160 Chap. XI. CREAM TESTING AT CREAMERIES________________ 176 Chap. XII. CALCULATION OF BUTTER AND CHEESE YIELDS___ 187 hap. Xi. CALCULATING DIVIDENDS —..-.- =... .--__ 203 Chap. XIV. CHEMICAL ANALYSIS OF MILK AND ITS PROD- ee ee eS oe Oe eee 217 i oh) ale Sa Sr eae er eee Lae ae 259 Table I. Composition of milk and its products. Table II. State aua city standards for dairy products. Table III. Quevenne lactometer degrees corresponding to the scale of the N. Y. Board of Health lactometers. Table IV. Valve of ee ee specific gravities from 1.019 to 1.0369. . S Table V. Correction table for specific gravity of milk. Table VI. Per cent. of solids not fat, corresponding to 0 to 6 per cent. of fat and lactometer readings of 26 to 36. Directions for the use of Tables VII, VIII, IX and XI. Table VII. Pounds of fat in 1 to 1,000 pounds of milk testing 3 to 5.35 per cent. ; Table VIII. Pounds of fat in 1 to 1,000 Ibs. of cream test- ing 12.0 to 50.0 per cent. fat. vl Testing Milk and Its Products. Table TX. Amount due for butter fat, in dollars and cents, at 12 to 20 cents per pound. Table X. Relative-value tables. Table XI. Butter chart, showing calculated yield of but- ter, in pounds, from 1 to 1,000 pounds of milk testing 3.0 to 5.3 per cent. of fat. Table XII. Overrun table, showing pounds of butter from 100 pounds of milk. Table XIII. Yield of cheese, corresponding to 2.5 to 6 per cent. of fat, with lactometer readings of 26 to 36. Table XIV. Comparisons of Fahrenheit and Centigrade (Celcius) thermometer scales. Table XV. Comparison of metric and customary weights and measures. Table XVI. Specific gravity and weight of one gallon of cream, arranged according to the per cent. of fat. Suggestions regarding the organization of co-operative ereameries and cheese factories. Constitution and by-laws for co-operative. factory associa- tions. Testing Milk and Its Products. INTRODUCTION. The need of a rapid, accurate and inexpensive method of determining the amount of butter fat in milk and other dairy products became more and more apparent. in this country and abroad, with the progress of the dairy industry, and especially with the growth of the factory system of butter and cheese making during the last few decades. So long as each farmer made his own butter and sold it to private customers or at the village grocery, it was not a matter of much importance to others whether the milk produced by his cows was rich or poor. But as creameries. and cheese factories mul- tiplied, and farmers in the dairy sections of our coun- try became to a large extent patrons of one or the other of these, a system of equitable payment for the milk or cream delivered became a vital question. 1. Nearly all the creameries in existence in this coun- try up to about 1890 were conducted on the cream- gathering -plan: the different patrons creamed their milk by the gravity process, and the cream was hauled to the creamery, usually twice or three times a week, where it was then ripened and churned. The patrons were paid per inch of cream furnished. This quantity was supposed to make a pound of butter, but cream 1 2 Testing Milk and Its Products. from different sources, or even from the same sources at different times, varies greatly in butter-producing capacity, as will be shown under the subject of cream testing (203). The system of paying for the number of creamery inches delivered could not therefore long give satisfaction. The proposition to take out a small portion, a pint or half a pint, of the cream furnished by each patron, and determine the amount of butter which these samples would make on being churned in so-called test churns, found but a very limited acceptance, on account of the labor involved and the difficulty of producing a first-class article from all the small batches of butter thus ob- tained. 2. The introduction of the so-called oil test churn in ereameries, which followed the creamery-inch system, marked a decided step in advance, and it soon. came into general use in gathered-cream factories (202). In this test, glass tubes of about 5g inch internal diameter and nine inches long, are filled with cream to a depth of five inches, and the cream is churned; the tubes are — then placed in hot water, and the column of melted butter formed at the top is read off by means of a scale showing the number of pounds of butter per creamery inch corresponding to different depths of melted but- ter. While the oil test is capable of showing the differ- ence between good and poor cream, it is not sufficiently accurate to make satisfactory distinctions between dif- ferent grades of good and poor cream.” As a result, 1 Refers to paragraph numbers. 2 Wis. Expt. Station, bulletin 12 (see also under 203). Introduction. 3 full justice cannot be done to different patrons of cream- erles where payments for cream delivered are made on the basis of this test. 3- In cheese factories, and since the introduction of the centrifugal cream separator, in separator creamer- ies, the problem of just payment for the milk furnished by different patrons was no less perplexing than in the ease of gathered-cream factories. By the pooling sys- tem generally adopted, each patron received payment in proportion to the number of pounds of milk deliv- ered, irrespective of its quality. Patrons delivering rich milk naturally will not be satisfied with this system. when they find that their milk is richer than that of their neighbors. The temptation to fraudulently in- crease the amount of milk delivered by watering, or to lower its quality by skimming, will furthermore prove too strong for some patrons; the fact that it was diffi- cult to prove any fraud committed, from lack of a re- liable and practical method of milk analysis, rendered this pooling system still more objectionable. 4. Formerly private dairymen and breeders of dairy cattle who desired to ascertain the butter-producing ca- pacities of the individual cows in their herds were obliged to do this by the cumbersome method of trial churnings: by saving the milk of each cow to be tested, for a day or a week, and churning separately the cream obtained. This requires a large amount of work when a number of cows are to be tested, and can not therefore be dene except with cows cf great excellence or by farm- ers having plenty of hired help. Here again the need of a practical milk test was strongly felt. 4 Testing Muk and Its Products. 5. Introduction of milk tests. The first method which fulfilled all reasonable demands of a practical and reliable milk and cream test was the Babcock test, invented by Dr. 8S. M. Babcock, of the Wisconsin agri- cultural experiment station. A description of the test was first published in July, 1890, as bulletin No. 24 of that Station, entitled: A new method for the estimation of fat in milk, especially adapted to creameries and cheese factories. This test, which is now known in all parts of the world where dairying is an important in- dustry, was not, however, the first method proposed for this purpose which could be successfully operated out- side of chemical laboratories. It was preceded by a num- ber of different methods, the first one published in this country being Short’s method, invented by the late F. G. Short, and described in bulletin No. 16 of Wisconsin experiment station (July 1888). 6. Short’s test. Jn this ingenious method, a certain quan- tity of milk (20 cc.1) was boiled with an alkali solution and afterwards with a mixture of sulfuric and acetic acids; a layer of insoluble fatty acids separated on top of the liquid and was brought into the graduated neck of the test bottles by addition of hot water; the reading gave the per cent. of fat in the sam- ple of milk tested. Short’s method did not find very wide application, both be- cause it was rather lengthy and its manipulations somewhat dif- ficult for non-chemists, and because several other methods were published shortly after it had been given to the public. 7. Other milk tests. Of these may be mentioned, besides the Babcock test already spoken of, the Failyer and Willard method,? Parsons’ method,*? Cochran’s test,* the Patrick or Iowa 1See 48, footnote. 2 Kansas experiment station report, 1888, p. 149. 8N. H. experiment station report, 1888, p. 69. ¢ Journal of Anal. Chem., III (1889), p. 381. Introduction. 5 station test,) and the Beimling (Leffmann and Beam) test.2 Of foreign methods published at about the same time, or previously, the Lactocrite,? Liebermann’s method,’ the Schmid,’ Thorner,® Nahm,’ Rose-Gottlieb,* sin-acid method,? and the Gerber sal- method” may be noted. 8. All these tests were similar in principle, the solids not fat of the milk being in all cases dissolved by the action of one or more chemicals, and the fat either measured as such in a narrow graduated tube, or brought into solution with ether, gasoline, etc., and a portion thereof weighed on evaporation of the solvent. While this principle is an old one, having been em- ployed in chemical laboratories for generations, its adaptation to practical conditions, and the details as to apparatus and chemicals used were, of course, new and different in each case. The American tests given were adopted to a limited extent within the states in which they originated and even outside of them, as in the case of the Short, Patrick and Beimling methods. The Babcock test, however, soon replaced the different methods mentioned, and during the past twenty years it has now been in almost exclusive use in creamer- ies and cheese factories in this country, where payments are made on the basis of the quality of the mille deliv- 1Ta. exp. sta., bull. No. 8, Feb. 1890; Lowa Homestead, June 14, 1889. 2 Vermont exp. sta., bull. No. 21, September, 1890. For description of these and other volumetric methods of milk analysis, see Wiley, Agri- cultural Analysis, Vol. III, p. 490 et seq. ; Wing, Milk and its Products, p. 33 et seq., and Snyder, Chemistry of Dairying, pp. 112-113. 3 Analyst, 1887, p. 6. Fresenius’ Zeitschr., 22, 383. SIbid., 27, 464. 6 Chem. Centralbl., 1892, 429. 7 Milch-Zeitung, 1894, No. 35; 1897, No. 50. 8 Landw. Vers. Stat., 40, 1. ® Milch-Zeitung, 1904, No. 27. 10 Milch-Zeitung, 1906, No. 8. 6 Testing Milk and Its Products. - ered, as well as in the routine work in experiment sta- tion laboratories, and among milk inspectors and pri- vate dairymen. 9. The Babcock test. The main cause why the Babeock test has replaced all competitors is doubtless to be sought, in its simplicity and its cheapness. It has but few manipulations, is easily learned, and is cheap, both in first cost and as regards running expenses. The test is furthermore speedy, accurate,1 and easily applied under practical conditions, and may therefore safely be considered the best milk test available at the present time. The method is applicable not only to whole milk, but to cream, skim milk, butter milk, whey, condensed milk, and (if a small scale for weighing out the sample is available) to cheese and butter.” With all its advantages, the Babcock milk test is not in every respect an ideal test. The handling of the very corrosive sulfuric acid requires constant care and attention; the speed of the tester, the strength of the acid, the temperature of the milk to be tested, and other points, require constant watching, lest the results ob- tained be too low or otherwise unsatisfactory. In the hands of careful operators the test can, however, ai- ways be relied upon to give most satisfactory results. 10. Foreign methods. In European countries five practical milk and cream tests, besides the Babcock test, 1for a summary of comparative analyses made by the Babcock test and gravimetric analysis up to 1892, see Hoard’s Dairyman, Oct. 7, 1892, p. 2560; also Schrott-Fiechtl, Milchzeitung, 1896, p. 188 et seq. 2The Babcock test, like the ether-extraction method gives, however, somewhat too low results in the case of skim milk (97). Introduction. | are in use at the present time, viz.: Gerber’s acid- butyronieter, the sin-acid (or no-acid) test, the lactocrite, De Laval’s butyrometer, and Fjord’s centrifugal cream test.? Of these tests the last ¢€ one has never, to our knowledge, been intro- duced into this country, and the first four only to a limited extent. 11. The Gerber method (fig. 1) is essentially the old Beimling method (7), worked out independently by the | Swiss chemist, Dr. N. Gerber. s In this test sulfurie acid of the same strength as in the Babcock test is used, and a ee ae ; 4 Fria. 1. The Gerber acid- small quantity of amyl alco- butyrometer. hol is added. The amyl alcohol facilitates the separation of the fat, but may introduce a source of error on account of impuri- ties contained therein, when the results obtained with a new lot of alcohol can not be checked against gravimetric analysis or against tests made with amyl] alcohol known to give correct results. This ‘method is, however, extensively used in European countries, hav- ing there practically replaced the Babcock test or been adopted in preference to it. lla. The sin-acid test was invented by the German chemist A. Sichler and published in 1904. In place of the sulfuric acid used in the Babcock and Gerber tests, Sichler employs a solution of 1The Lister-Babcock milk test advertised in English papers and known as such in England, is the regular Babcock test, to which the English manufacturers have affixed their name; the same applies to the Ahlborn-Babcock and the Krugmann-Babcock methods. 2 Gerber, Die praktische Milchpriifung, 7th edition, 1900. 3 Milchztg., 1904, p. 417. The word sin (sine) is Latin and means without ; hence, when introduced into this country in 1909 the method was called the no-acid test. 8 Testing Milk and Its Products. Rochelle salts, sodium sulfate and sodium hydroxid.’ 150 ce. of this mixture of salts are dissolved in 1 liter of water. In testing milk, 11 ec. of this solution and 0.6 ce. of ‘‘sinol’’ (isobutylaleohol) are added to 10 ce. of milk. After thorough mixing of the milk and solution the test bottles are placed in water of 113° F. for 3-5 minutes, when they are shaken till all the curd dissolves. They are then revolved in a centrifuge for 3 minutes and the results read off. By heating the bottles for 1 hour in boiling hot water correct results may be obtained without the use of a centrifuge. The main advantages of the method appear to lie in this fact and in that the use of a corrosive acid is avoided. ie 12. The Lactocrite was one of the earliest practical milk tests introduced. It was invented by De Laval in 1886. The acids used in this test are lactic acid (originally, acetic acid) with a mixture of hydrochloric and sulfuric acids. This test is now but rarely met with. e Se "Fre. 2. De Laval’s butyrometer. 13. In the De Laval butyrometer (fig. 2) the same acid is used as in the Babcock test, but the tubes employed and the manipulations of the method differ materially from this test; a smaller sample of milk is taken (only 2 cc.) and a correspond- ingly small quantity of acid used. Where a large number of 1 Barthel-Goodwin, Methods used in Examination of Milk and Dairy Products, p. 77. Introduction, 9 milk samples are tested every day, as, for instance, in milk control stations, the butyrometer may be preferable to the Babcock test; but it requires more skill of the operator and does not work satis- factorily in case of sour, loppered, or partially churned milk. 14. Fjord’s centrifugal cream tester’ (fig. 3) is exten- sively used nm Denmark and is mentioned in this conncetion as it furnishes, as a rule, a reliable method for comparing the qual- ity of different lots of milk. The method was published in 1878, by the late N. J. Fjord, director of the state experiment station in Copenhagen, through whose exertions and on whose authority it was introduced into Danish creameries in the middle of the eighties. No chemicals are added in this test, the milk being simply placed in glass tubes, seven inches long and about two- thirds of an inch in diameter, and whirled for twenty minutes at a rate of 2000 revolutions per minute at 55°C (131°F.). The reading of the cream layer thus obtained gives the per cent of cream, and not of butter fat, in the sample tested. One hundred and ninety-two sam- ples of milk can be tested ; simultaneously. Within the limits of normal Danish herd milk, the results obtained cor- 7] respond to the per cents of fat (j}}] present in the samples, one per cent. of cream being equal to es se about 0.7 per cent. of fat; Fic.3. Fjord’s centrifugal cream outside of these limits the test hi Kis is, however, unreliable, especially in case of very rich milk and strippers’ milk. Only sweet milk can be tested by this method. Milk tests proper, like the Gerber, Babcock and De Laval tests, have during recent years been introduced into Denmark and are used in some creameries.” 1State Danish experiment station, Copenhagen, sixth and ninth re- ports, 1885-7. 2 Among foreign milk tests in use abroad should also be mentioned the Lindstrom butyrometer and the Wollny refractometer, both of which, in the hands of trained chemists, may prove better adapted for use where a very large number of samples are to be tested at a time, than any other available milk test. CHAPTER I. COMPOSITION OF MILK AND ITS PRODUCTS. Before taking up the discussion of the Babcock milk test, a brief description of the chemistry of milk and its products is given, so that the student may understand what are the components of dairy products, and the re- lation of these to each other. Only such points as have a direct bearing upon the subject of milk testing and the use of milk tests in butter and cheese factories or private dairies will be treated in this chapter, and the reader is referred to standard works on dairying for more detailed information in regard to the composition of dairy products. 15. Composition of milk. Milk is composed of the following substances: water, fat, casein, albumen, milk sugar, and ash. A few other substances are present in small quantities, but they are hardly of sufficient prac- tical importance to be considered here. The com- ponents of the milk less the water are known collect- ively as milk solids or total solids, and the total solids less the fat, i. e., casein, albumen, milk sugar, and ash, are often spoken of as solids not fat or the non-fatty milk solids. The milk serum includes all components uf the milk less the fat; the serwm solids are therefore another name for the solids not fat; when given, they are, however, generally calculated to per cent. of milk serum, not of milk. If, e. g., a sample of milk contains Composition of Milk and Its Products. 11 nine per cent. of solids not fat, and three per cent. of fat, the milk serum will make up 97 per cent. of the _ 2 9x1 milk, and the serum solids, ie ote 2 — 928 per cent. of the milk serum. 16. Water. The amount of water contained in cow’s milk ranges from 82 to 90 per cent. Normal cow’s milk will not, as a rule, contain more than 88 per cent. of water, nor less than 84 per cent. In states where there are laws regulating the sale of milk, as is the-case in twenty-two states of the Union (see Appendix, Table Il), the maximum limit for water in milk in all instances but one (South Carolina) is 88 per cent. ; the state men- tioned allows 88.5 per cent. of water in milk offered for sale within her borders. ‘he effect of fraudulently increasing the water content of milk by watering is con- sidered under Adulteration of Milk (121). 17. Fat. The fat in milk is not in solution, but sus- pended as very minute globules, which form an emul- sion with the milk serum; the globules are present in immense numbers, viz., on the average about one hun- dred millions in a single drop of milk; a quart of milk will contain about two thousand billions of fat globules, a number written with thirteen figures. The sizes of the globules in the milk from the same cows vary ac cording to the stage of the period of lactation, the glob- ules being largest at the beginning of the lactation period, and gradually decreasing in size with its prog- ress. Different breeds of cows have fat globules of different average sizes; the Channel Island cows are | thus noted for the relatively large fat globules of their 12 Testing Milk and Its Products. milk, while the lowland breeds, the Ayrshire, and other breeds have uniformly smaller globules. The diameter of average sized fat globules in fresh milkers is about .004 millimeter, or one six-thousandth of an inch; that is, it takes about six thousand such globules placed side by side to cover one inch in length. The globules of any sample of milk vary greatly in size; the largest globules are recovered in the cream when the milk is set or run through a cream separator, and the smallest ones remain in the skim milk; thoroughly skimmed sep- arator skim milk contains only a small number of very minute fat globules. Milk fat is composed of so-called glycerides of the fatty acids, 1. e., compounds of the latter with glycerin; some of the fatty acids are insoluble in water, viz., palmitic, stearic, and oleic acids, while others are solu- ble and volatile, the chief ones among the latter being butyric, caprylic, and capronic acids. The glycerides of the insoluble fatty acids make up about 92 per cent. of the pure milk fat; about 8 per cent. of the glycer- ides of volatile fatty acids are therefore found in nat- ural milk- (and butter-) fat. The distinction between natural and artificial butter lies mainly in this point, since artificial butter (butterine, oleomargarine) as well as other solid animal fats contain only a very small quantity of volatile fatty acids. The glycerides of the volatile fatty acids are unstable compounds, and are easily decomposed through the action of bacteria or light; the volatile fatty acids thus set free, principally butyrie acid, are the cause of the unpleasant odor met with in rancid butter. Composition of Milk and Its Products. 13 Cow’s milk generally contains between three and six per cent. of fat; in American milk we find, on the average, toward four per cent. of fat. The milk from single cows in perfect health will occasionally go below or above the limits given, but mixed herd milk rarely falls outside of these limits. The standard adopted by the U. S. government for fat in milk is 3.25 per ct. The legal standard for fat in milk in most states of the Union is 3 per cent.; Rhode Island allows milk contain- ing 2.5 per cent. of fat to be sold as pure, while Georgia and Minnesota require it to contain 3.5 per cent., and Massachusetts 3.7 per cent. (in the months of May and June; see Appendix, Table IT). 18. Casein and albumen. These belong to the so- called nitrogenous substances, distinguished from the other components of the milk by the fact that they con- tain the element nitrogen. Another name is albwmin- oids or protein compounds. Casein is precipitated by rennet in the presence of soluble calcium salts, and by dilute acids and certain chemicals; albumen is not acted upon by these agents, but is coagulated by heat, a tem- perature of 170° F. being sufficient to effect a perfect coagulation. The casein, fat, and water, are the main components of nearly all kinds of cheese. In the manu- facture of cheddar and most other solid cheeses, the casein is coagulated by rennet, and the curd thus formed holds fat and whey mechanically, the latter containing in solution small quantities of non-fatty milk solids. The albumen goes into the whey and is lost for cheese making; in some countries it is also made into cheese by evaporating the whey under constant 14 Testing Milk and Its Products. stirring; whole milk of cows or goats is often added and incorporated into such cheese (primost, gjetost). Casein is present in milk partly in solution, in the same way as milk sugar, soluble ash-materials and albu- men, and partly in suspension, in an extremely fine col- loidal condition, mixed or combined with insoluble eal- cium phosphates. The casein and calcium phosphates in suspension in milk may be retained on a filter made of porous clay (so-called Chamberland filters). About 80 per cent. of the nitrogenous compounds of normal cow’s milk are made up of casein; the rest is largely albumen. If the amount of casein in milk be determined by precipitation with rennet or dilute acids, and the albumen by boiling the filtrate from the casein precipitate, it will be found that the sum of these two compounds do not make up the total quantity of nitro- genous constituents in the milk. The small remaining portion (about five per cent. of the total nitrogenous constituents) has been ealled by various authors, globu- lin, albumose, hemi-albumose, nuclein, nucleon, proteose, ete. The nitrogenous constituents of milk are very un- stable compounds, and their study presents many and creat difficulties; as a result we find that no two scien- tists who have made a special study of these compounds agree as to their properties, aside from those of casein and albumen, or their relation to the nitrogenous sub- stances found elsewhere in the animal body. For our purpose we may, however, consider the nitrogen com- pounds of milk as made up of casein and albumen, and the term casein and albumen, as used in this book, is meant to include the total nitrogenous constituents of Composition of Milk and Its Products. 15 milk, obtained by multiplying the total nitrogen con- tent of the milk by 6.25.7 The quantity of casein in normal cow’s milk will vary from 2 to 4 per cent., and of albumen, from .5 to .8 per eent. The total content of casein and albumen ranges between 2.5 and 4.6 per cent, the average being about 3.2 per cent. Milk with a low fat content will contain more casein and albumen than fat, while the reverse is generally true in case of milk containing more than 3.5 per cent. of fat. 19. Milk sugar or lactose belongs to the group of organic compounds known as carbohydrates. It is a commercial product manufactured from whey and is obtained in this process as pale white crystals, of less sweet taste and less soluble in water than ordinary sugar (cane sugar, sucrose). About 70 per cent. of the solids in the whey, and 33 per cent. of the milk solids, are composed of milk sugar. When milk is left standing for some time, viz., from one to several days, according to its cleanliness and the temperature of the surrounding medium, it will turn sour and soon become thick and loppered. This change in the composition and appearance of the milk is brought about through the action of acid-forming bacteria on the milk-sugar. These are present in ordi- nary milk in immense numbers, and under favorable eonditions of ei eeebed wigsiwek edie on 1The factor 6.25 is Seas used for obtaining the casein and albu- men from the total nitrogen in the milk, on the theory that protein compounds contain 16% N.; the factor 6.87 would, however, be more correct, since casein and albumen, according to oe Lys authorities, contain on the average 15.7 per cent of nitrogen (; 24 0~6.37) 16 Testing Milk and Its Products. the milk sugar as they grow, and decomposing it into lactic acid. When this change alone occurs, there is not necessarily a loss in the nutritive value of the milk, since milk sugar breaks up directly into lactic acid. This is shown by the following chemical formula: C5H,,0;,H,0 (lactose) 4 (C,H 0, (Clacheacia) = Ordinarily the souring of milk is, however, more complicated, and other organic bodies, like butyric acid, aleohol, ete., and gases like carbonic acid are formed, resulting in a loss in the feeding value of the milk. While sour milk may therefore contain a somewhat smaller proportion of food elements than sweet milk, it will generally produce better results when fed to farm animals, especially pigs, than is obtained in feed- ing similar milk in a sweet condition. The cause of this may lie in the stimulating effect of the lactic acid of sour milk on the appetites of the animals, or in its aid- ing digestion by increasing the acidity of the stomach juices. That the souring of milk is due to the activities of bacteria present therein is shown clearly by the fact that sterile milk, i. e., milk in which all germ life has - been killed, will remain sweet for any length of time when kept free from infection. The amount of milk sugar found in normal cow’s milk varies from 3.5 to 6 per cent., the average content being about 5 per cent.; in sour milk this content is decreased to toward 4 per cent. 1QOne molecule of milk sugar is composed of 12 atoms of carbon (C), 22 atoms of hydrogen (H), 11 atoms of oxygen (O), and one molecule of water (H,O). In the same way, the lactic acid molecule consists of 3 atoms of carbon, 6 atoms of hydrogen, and 3 atoms of oxygen. Composition of Milk and Its Products. LT 20. Ash. The ash or mineral substances of milk are largely composed of chlorids and phosphates of sodium, potassium, magnesium and calcium; iron oxid and sul- furic and other acids are also present in small quanti- ties among the normal mineral milk components. The amounts of the different bases and acids found in milk ash have been determined by a number of chemists; the average figures obtained are given in the following table, calculated per 100 parts of milk (containing .75 per cent. of ash) and per 100 parts of milk ash. Mineral Components of Milk. In per cent of milk. In per cent of ash. Potassium oxid (K,O) --------- .19 per ct. 25.64 per ct. Sodium oxid (Na,Q)_-....---- .09 12.45 Meare ACA) ) oe i 8 18 24.58 Macnesia. (Met) 2... - .02 3.09 ieon-omid (FeO, ) 22-2— 2 .002 34 Phosphoric anhydrid (P.0,;)--- .16 21.24 RS nS Se 12 16.34 .762 per ct. 103.68 per ct. Less oxygen, corresponding to COLLUNS 1 Ee So eo .012 3.68 .75 100.00 The combinations in which the preceding bases and acids are contained in the milk are not known with cer- tainty. According to Sdldner, 36 to 56 per cent. of the phosphoric acid found in milk, and from 53 to 72 per cent. of the lime, are present in suspension in the milk as di- and tri-calecium phosphates, and may be filtered out by means of Chamberland filters (18), or by long continued centrifuging (Babcock'). The rest of the ash constituents are dissolved in the milk serum. 1 Wisconsin experiment station report 12, p. 93. 9 w 18 Testing Milk and Its Products. The ash content of normal cow’s milk varies but lit- tle, as the rule only between .6 and .8 per cent., with an average of .7 per cent. Milk with a high fat content - generally contains about .8 per cent. of ash; strippers’ milk always has a high ash content, at times even ex- ceeding one per cent. Ordinarily, the mineral constitu- ents are least liable to variations of any of the com- ponents of the milk. 21. Other components. Besides the milk constitu- ents enumerated and described in the preceding pages, normal milk contains a number of substances which are present in but small quantities and have only scientific interest, such as the milk gases (carbonic acid, oxygen, nitrogen), citric acid, lecithin, cholesterin, urea, hypo- xanthin, lactochrome, ete. 22. Average composition. The average percentage composition of cow’s milk will be seen from Table I in the Appendix. The following statement shows the lim- its within which the components of normal American cows’ milk are likely to come: Minimum. Mazimum. Average. Water 222 Se ee 82.0 per ct. 90.0 per ct. 87.4 per ct. Wasa Lf eee aie 2.3 7.8 Sah Casein and albumen ___—s_-22.5 4.6 3.2 Mak: susarice) Soe esse 3.5 6.0 5.0 7X1 1 eee SE ee oe Boe Oe 6 9 Ei 23. Colostrum milk. The liquid secreted directly after parturition is known as colostrum milk or biest- ings. It is a thick, yellowish, viscous liquid; its high contents of albumen and ash are characteristic, and also its low content of milk sugar. Owing to the large quan- tity of albumen which colostrum contains, it will coagu- Composition of Milk and Its Products. 19 late on being heated toward the boiling point. In the course of three or four days the secretion of the udder oradually changes from colostrum to normal milk; the milk is considered fit for direct consumption or for the manufacture of cheese and butter, when it does not co- agulate on boiling and is of normal appearance as re- gvards color, taste, and other properties. For composi- tion of colostrum milk, see Appendix, Table I. 24. Composition of milk products. In addition to its use for direct consumption, milk is the raw-material from which cream, butter, cheese, and condensed milk are obtained. When milk is left standing for some time or subjected to centrifugal force, it will separate into two distinct parts, cream and skim milk. The proportion of each part which is obtained, and their chemical composition, will depend on the method by which the separation is effected; in the so-called gravity process where the eream is separated on standing—either in shallow pans in the air, 0: in deep cans, submerged in cold water—a less complete separation is reached, since the skim milk obtained is richer in fat than when the separation takes place through the action of centrifugal force. In modern creameries the milk is now always skimmed by means of cream separators. Separator cream will contain from 15 to 50 per cent. of fat, according to the adjustment of the separator and of the milk supply; ordinarily it contains about 25 per cent. of fat. Cream of average quality, in addition to the fat content given, consists of about 66 per cent. of water, 3.8 per cent. 20 Testing Milk and Its Products. casein and albumen, 4.3 per cent. milk sugar, and .5 per cent. ash. . The skim milk is made up of the milk serum (15) and a small amount of fat, viz., toward .4 per cent. when obtained by the gravity process, and less than .2 per cent. in the case of separator skim milk. Milk set in shallow pans in the air, or in deep cans in water above 60° F., will give skim milk containing one-half to over one per cent. of fat. Skim milk is used as a food for young farm animals or as human food, and in this country only in exceptional cases, for the manufacture of cheese. 25. Cream is used for the manufacture of butter or for direct consumption. In the former case a certain amount of acidity is generally allowed to develop there- in previous to the churning process. This secures a more complete churning and produces peculiar flavors in the butter, without which it would seem insipid to most people. Nearly all butter made in this coun try is .salted before being placed on the market Salt is a preservative and for a limited length of time prevents butter from spoiling. Unsalted butter made from sweet cream is a common food article in Southern and Middle Europe, but only an insignificant amount is manufactured and consumed in America; salted butter made in Europe also contains considerably less salt than American butter (see Appendiz, Table I). Butter contains all the fat of the cream except a small portion which goes into the butter milk, and a small unavoidable mechanical loss incident to the handling of the products. Butter should contain at least 80 per Composition of Milk and Its Products. 21 cent. of fat and ordinarily contains about 83 per cent.; besides this amount of fat, butter is generally composed of about 13 per cent water, 1 per cent curd and lactic acid, and 3 per cent salt. Butter milk has a composition similar to skim milk, but varies much more than this product, according to the acidity, temperature, and thickness of the cream, and other churning factors. It contains about 9 per cent. of solids, viz., milk sugar (and lactic acid) 4 per cent., casein and albumen 4 per cent., fat .3 per cent., and ash .7 per cent. 26. The quantities of butter and by-products obtained in the manufacture of butter are as follows: 1000 lbs. of milk of average quality will give about 850 lbs. of skim milk and 145 lbs. of cream (separator slime and mechanical loss, 5 lbs.) ; this amount of cream will make about 42 lbs. of butter and 100 lbs. of butter milk (me- chanical loss, 3 lbs.). 27. In the manufacture of American cheddar cheese, whole milk is heated to about 86° F., and asmall amount of rennet extract is added, which coagulates the casein; the albumen of the milk is not precipitated by rennet and remains in solution (18). ‘‘Green’’ cheese, as taken from the press, is made up, roughly speaking, of 37 per cent. of water, 34 per cent. of fat, 24 per cent. of albu- minoids (nearly all casein), and about 5 per cent. of milk sugar, lactic acid, and ash (largely salt). In the curing of cheese there is some loss by drying, but the main changes occur in the breaking up of the firm curd into soluble and digestible nitrogenous compounds, pep- tones, amids, etc. 22 Testing Milk and Its Products. Whey is the by-product obtained in the manufacture of cheese. It consists of water and less than 7 per cent. of solids; of the latter about 5-per cent. is milk sugar, .8 per cent. albumen, .6 per cent. ash, and .3 per cent. fat. Whey is generally used for feeding farm animals; it is the raw-material from which milk sugar and whey cheese are made. 28. Condensed milk is manufactured from whole milk or from partially skimmed milk. In many brands a large quantity of sugar (25 per cent. or more) is added to the condensed milk in the process of manufacture so as to secure perfect keeping quality in the product. Brands to which no sugar has been added are also on the market, and in case of such brands the relation be- tween the various solid constituents of the condensed milk will be essentially the same as that between the constituents of milk solids. Condensed milk should con- tain at least 7.7% fat, and must be free from preserva- tives and other foreign substances (except sugar). Tables are given in the Appendix showing the aver- age composition of the various milk products. Questions. 1. What is the average composition of cow’s milk; state briefly the properties of the various constituents. 2. What is meant by total solids; solids not fat; milk serum; serum solids? 3. What is colostrum milk? Give its average composition, and in what particulars it mainly differs from normal milk. 4. Give the average composition of cream, skim milk, butter- milk, whey, butter and cheddar cheese. 5. Explain the distribution of the components of milk in (a) butter-making, (b) cheese-making. CHAPTER Il. SAMPLING MILK. 29. The butter fat in milk is not in solution, like sugar dissolved in water, but the minute fat globules or drops, in which form it occurs, are held in suspension in the milk serum (17). Being lighter than the serum, the fat globules have a tendency to rise to the surface of the milk. If, therefore, a sample of milk is left standing for even a short time, the upper layer will contain more fat than the lower portion. This fact should always be borne in mind when milk is sampled. The rapidity with which fat rises in milk can be easily demonstrated by allowing a quantity of sweet milk to stand in a cylinder or a milk can for a few minutes, and testing separately the top, middle and bottom layer of this milk. The amount of mixing necessary to evenly distribute the constituents of milk throughout its mass may be as- certained by adding a few drops of cheese color to a quart of milk. The yellow streaks through the milk will be noticed until it has been poured several times from one vessel to another, when the milk will have a uniform pale yellow color. Stirring with a stick or a dipper will not produce an even mixture so quickly or so completely as pouring the milk a few times from one vessel to another. In sampling milk for testing it should always: be mixed just before the milk is measured into the bottle ; if several tests are made of a sample, the milk should be mixed before each sampling. 24 Testing Milk and lis Products. 30. Partially churned milk. A second difficulty sometimes met with in sampling whole milk arises from the fact that a part of the butter fat may be separated in the form of small butter granules, by too zealous mix- ing or by reckless shaking in preparing the sample for testing. This will happen most readily in case of milk from fresh cows or of milk containing exceptionally large fat globules. When some of the butter granules are thus churned out, they quickly rise to the surface of the milk after pouring and cannot again be incorporated in the milk by simple mixing; it is, therefore impossi- ble to obtain a fair sample of such milk for testing without taking special precautions which will be ex- plained in the following. The granules of butter may be so small as to pass into the pipette with the milk and the quantity measured thus contain a fair proportion of them, but they will be found sticking to the inside of the pipette when this is emptied, and thus fail to be carried into the test bottle with the milk. A similar partial churning of the milk will sometimes take place in the transportation cans. When such milk is received at the factory, the butter granules are caught by the strainer cloth through which the milk is poured, and are thus lost both to the factory and to the farmer. This separated fat cannot be added to the cream or to the granular butter, without running the risk of mak- ing mottled butter, and it will not enter into the sam- ple of milk taken for testing purposes. When milk samples are sent by mail or express in small bottles, or carried to the place of testing, they often arrive with lumps of butter floating in the milk or sticking to the glass. This churning of the milk can Sampling Milk. 29 be easily prevented by completely filling the bottle or the can. If there is nospace left for the milk in which to splash around, the fat will not be churned out in transit. 31. Approximately accurate results may generally be obtained with a partially churned sample of milk, if a teaspoonful of ether be added to it. After adding the ether, cork the bottle and shake it until the lumps of butter are dissolved. This ether solution of the butter will mix with the milk and from the mixture a fairly . Satisfactory sample may generally be taken. The dilu- tion of milk by the ether introduces an error in the testing, and only the smallest quantity of ether neces- sary to dissolve the lumps of butter should be used. If desired, a definite quantity of ether, say five per cent. of the volume of the sample of milk to be tested, may be added; in such cases the result of the test must be increased by the per cent. of ether added. EXAMPLE.—To a 4-oz. sample (120 ec.) of partially churned milk, 5 per cent., or 6 ec. of common ether are added; the mix- ture gave an average test of 4.2 per cent. The test must be in- creased by ;3,X4.2—.21 per cent., and the original milk there- fore contained 4.2+-.21—4.41 per cent. of fat. Milk containing ether must be mixed cautiously with acid in making a test, so as to avoid a loss of the contents of the bottle by the sudden boiling of the ether due to the heat evolved in mixing the milk and the acid. Instead of adding ether to partially churned sam- ples, the milk may be heated to about 110° F. for a few minutes, so as to melt the butter granules; the sample is now shaken vigorously until a uniform mix- ture of milk and melted butter is obtained, and a pi- petteful is then quickly drawn from the sample. 26 Testing Mik and Its Products. 32. Sampling sour milk. When milk becomes sour, the casein is coagulated and the mechanical condition of the milk thereby changed so as to render difficult a cor- rect sampling. The butter fat is not, however, changed in the process of souring; this has been shown by one of us, among others, in a series of tests which were measured from one sample of sweet milk into six test bottles. A test of the milk in one of these test bottles was made every month for six months, and approxi- mately the same amount of fat was obtained in the tests throughout the series, as was found originally in the milk when tested in a sweet condition. If the milk is in condition to be sampled, souring does not there- fore interfere with its being tested by the Babcock test or with the accuracy of the results obtained. In order to facilitate the sampling of sour or lop- pered milk, some chemical may be added which will re- dissolve the coagulated casein and produce a uniform mixture that can be readily measured with a pipette. Any alkali (powdered potash or soda, or liquid ammo- nia) will produce this effect. Only a very small quan- tity of powdered alkali is necessary for this purpose. The complete action of the alkali on sour milk requires a little time, and the operator should not try to hasten the solution by adding too much alkali. An excess of alkali will often cause such a violent action of the sul- furie acid on the milk to which the acid is added (on account of the heat generated or the presence of car- 1See Hoard’s Dairyman, April 8, 1892. The same holds true for cream, as shown by Winton (U. S. Dept. Agr., Div. of Chemistry, bull. 43, p. 112). As to length of time Babcock tests will keep, see Vt. exp. sta., bull. 106. Testing Milk and Its Products. 27 bonates in the alkali) that the mixture will be thrown out of the neck of the test bottle when this is shaken in mixing the milk and the acid (37). When powdered alkali is added to the milk, it should be allowed to stand for a while, with frequent shaking, until the curd is all dissolved and an even translucent liquid is ob- tained. Such milk may become dark-colored by the ac- tion of the alkali, but this color does not interfere with the accuracy of the test. Instead of powdered soda or potash, these substances dissolved in water (soda or potash lye), or strong am- monia, may be used for the purpose of dissolving the coagulated casein in sour milk. In this case, a definite proportion of alkali solution must be taken, however, 5 per cent. of the volume of milk being usually sufficient, and the results obtained are increased accordingly. 33. Sampling frozen milk. When milk freezes, it separates into two distinct portions: Milk crystals, largely made up of water, with a small admixture of fat and other solids, and a liquid portion, containing nearly all the solids of the milk. In sampling frozen milk it is therefore essential that the liquid and the frozen part be warmed and thoroughly mixed by pouring gently back and forth from one vessel into another; the sam- ple is then taken and the test proceeded with in the ordinary manner (36). Questions. 1. What precautions must be taken in sampling milk? Give reasons. 2. How can a fair sample be taken of (a) partially churned milk, (b) sour milk, (c) frozen milk? © 3. If 15 ec. of ammonia are added to 500 cc. of sour milk, and a test of 3.45 obtained, what is the correct test of the milk? CHAPTER III. THE BABCOCK TEST. 34. The Babcock test is based on the fact that strong sulfuric acid will dissolve all non-fatty solid constitu- ents of milk and other dairy products, and thus enable the fat to separate on standing. To effect a speedy and complete separation of the fat, the bottles holding the mixture of milk and acid are placed in a centrifugal ma- chine, a_ so-called tester, and whirled for four minutes; hot water is then added so as to bring the liquid fat into the graduated neck of the test bottles, and after a repeated whirling, the length of the column of fat is read off, showing the per cent. of fat contained in the sample tested. Fig. 4. The first Babcock tester made. The Babcock Test. 29 Sulfurie acid is preferable to other mineral acids for the purpose mentioned, on account of its affinity to water; when mixed with milk, the mixture heats greatly, thus keeping the fat liquid without the application of ‘artificial heat and rendering possible a distinct reading of the column of fat brought into the neck of the test bottles. So far as is known, any kind of milk can be tested by the Babcock test. Breed, period of lactation, qual- ity or age of the milk are of no importance in using this method, so long as a fair sample of milk can be secured. In eases of samples of milk or other dairy products rich in solids it requires a little more effort to obtain a thorough mixture with the acid than with dairy prod- ucts low in solids, like skim milk or whey, which may be readily mixed with the acid. A.— DIRECTIONS FOR MAKING THE TEST. 35. The various steps in the manipulation of the Babcock test are discussed in the following pages; at- tention is drawn to the difficulties which the beginner and others may encounter in the use of the test, and the necessary precautions to be observed in order to obtain accurate and satisfactory results are explained in detail. The effort has been to treat the subject ex- haustively and from a practical point of view, so that persons as yet unfamiliar with the test may turn to the pages of this book for help in difficulties which they may meet in their work in this line. 36. Sampling. The sample to be tested is first mixed by pouring the milk from one vessel to another two or 30 Testing Milk and Its Products. three times, so that every portion thereof will contain a uniform amount of butter fat (29). The measuring pipette (fig. 6), which has a capacity of 17.6 cubic centimeters,’ is filled with a the milk immediately after the vil mixing is completed, by suek- q ing the milk into it until this rises a liftle above the mark around the stem of the pipette; : the forefinger is then quickly placed over the end of the pi- 7°) pette before the milk runs down i+ below the mark. By slightly | releasing the pressure of the q finger on the end of the pipette, the milk is now allowed to run down until it just reaches the mark on the stem; the quantity | of milk contained in the pi- | pette will then. if this is cor- : rectly made, be exactly 17.6 ce. The finger should be fairly dry in measuring out the milk so that the delivery of milk may be- readily checked by gentle pressure on the upper end of the pipette. The point of the pipette is 7 — now placed in the neck of a Fic. 5. Babcock milk test bottle. Babeock test bottle (fig. 5), = ate Oe ee 1See p. 45, foot note. The Babcock Test. of and the milk is allowed to flow slowly down the inside of the neck. Care must be taken that none of the milk measured out is lost in this transfer. The portion of the milk remaining in the point of the pipette is blown into the test bottle. The best and saf- est manner of hold- ing the bottle and the pipette in this trans- fer is shown in fig. 7. Eig. 8 shows a position which should be avoided, since by holding the bottle in this way, there is Fie. 7. The right way of emptying pipette into test bottle. 37. Adding acid. “Pit PLA It bleed & wy c= t danger that some of the milk may completely fill the neck of the bottle, and as a result, flow over the top of the neck. Pipettes, the lower part of which slip read- ily into the necks of the test bottles, may be emptied by lowering the pipette into the neck of the bottle till it rests on its rim, when the milk is allowed to run into the test bottle. The acid cylinder (fig. 9) hold- ing 17.5 ec., is filled to the mark with sulfurie acid ot 32 Testing Milk and Its Products. a specific gravity of 1.82-1.83. This amount of acid is carefully poured into the test bottle containing the milk. In adding the acid, the test bottle is conveniently held at an angle (see fig. 7), so that the acid will run down the wall of the bottle and not run in a small stream into the center of the milk, the @ : bottle being slowly turned around and the neck thus cleared of adhering milk. By pouring the acid into the middle of the test bottle, there is also a danger of com- pletely filling this with acid, in which case the plug of acid formed will be pushed over the edge of the neck by the expansion of the air in the bottle, and may be spilled on the hands of the operator. The milk and the acid in the test bottle should be in two distinct layers, without much of a black an band of partially Z mixed liquids be- tween them. Such Fic. 8. The wrong way of emptying pipette a dark layer is of- into test bottle. ten followed by an indistinct separation of the fat in the final reading. The cause of this may be that a par- tial mixture of acid and milk before the acid is diluted The Babcock Test. 33 with the water of the milk will bring about too strong an action of the acid on this small portion of the milk, and thus char the fat contained therein. The appear- ance of black flocculent matter in or below the col- umn of fat which generally results, in either case renders a correct measurement difficult and at times even impossible; if the black specks occur in the fat column itself, the readings are apt to be too high; if below it, the difficulty comes in decid- ing where the column of fat begins. 38. Mixing milk and acid. After add- ing the acid, this is carefully mixed with a7 the milk by giving the test bottle a rotary J EN " motion. In doing this, care should be a taken that the liquid is not shaken into acid cylinder. the neck of the test bottle. When once begun, the mix- ing should be continued until completed; a partial and interrupted mixing of the liquids will often cause more or less black material to separate with the fat. when the test is finished. Clots of curd which separate at first by the action of the acid on the milk, must be entirely dissolved by continued and careful shaking of the bot- tle. Beginners sometimes fail to mix thoroughly the milk and the acid in the test bottle. As the acid is much heavier than the milk a thin layer of it is apt to be left unnoticed at the bottom of the bottle, unless this is vigorously shaken toward the end of the operation. The mixture becomes hot by the action of the acid on the water in the milk and turns dark colored, owing to the effect of the strong sulfuric acid on the nitrogenous constituents and the sugar in the milk. 9 v 34 Testing Milk and Its Products. Colostrum milk or milk from fresh cows will form a violet colored mixture with the acid, due to the action of the latter on the albumen present in such milk in considerable quantities (23). When milk samples are preserved by means of potas- sium bichromate (190), and so much of this material has been added that the milk has a dark yellow or reddish color, the mixture of milk and acid will turn greenish black, and a complete solution is rendered extremely difficult on account of the toughening effect of the bi- chromate on the precipitated casein. This difficulty is still more pronounced with milk preserved with form- aldehyd. 39. Whirling bottles. After the milk and the acid have been thoroughly mixed, the test bottle is at once placed in the centrifugal machine or tester and whirled for four or five minutes at a speed of 600 to 1200 revo- lutions per minute, according to the diameter of the tester (66). It is not absolutely necessary to whirl the test bottles in the centrifuge as soon as the milk and the acid are mixed, although this method of procedure is much to be preferred; they may be left in this condi- tion for any reasonable length of time (24 hours, if necessary) without the test being spoiled. If left until the mixture becomes cold, the bottles should, however, be placed in warm water (of about 160° F.) for about fifteen minutes before whirling. Four minutes at full speed is sufficient for the first whirling of the test bottles in the centrifuge; this will bring all fat to the surface of the liquid in the bottle. ~The Babcock Test. | 315, 40. Adding water. Hot water is now added by means of a pipette or some special device (10 in fig. 58),? until the bottles are filled to near the seale on the neck (80). The bottles are whirled again at full speed for one min- ute, and hot water added a second time, until the tower part of the column of fat comes within the scale on the neck of the test bottle, preferably to the 1 or 2 per cent. mark, so as to allow for the sinking of the column of fat, due to the gradual cooling of the contents of the bottle. By dropping the water directly on the fat in the second filling, the column of fat will be washed free from light floeceulent matter, which might otherwise be - o jth ett ¢ i i Fic. 10. Measuring the column of fat in a Babcock test bottle. entangled therein and render the reading uncertain or too high. A final whirling for one or two mip- utes completes the separation of the fat. 41. Measuring the fat. The amount of fat in the neck of the bottle is measured by the scale or eraduations on the neck. Each division of the scale represents two-tenths of one per cent. of fat, and the space filled by the fat shows the per cent. of butter fat contained in the sample tested. The fat is measured from the lower line of separation between the fat and the water, to the top of the fat column, at the point b, shown in the figure, the reading being thus taken from a to b, and not to c or to d. Comparative 1See under 204. 36 Testing milk and tts Products. gravimetric analyses have shown that the readings ob- tained in this manner give correct results. While the lower line of the fat column is nearly straight, the upper one is curved, and errors in the reading are therefore easily made, unless the preceding rule is observed. Results with 8% bottles (44a) agree well with those obtained with the 10% bottles, when care is taken to read the fat column to the extreme top of the menis- eus. This appears especially thin in the former bottles and cannot be seen quite as readily as in the 10% bottles. The fat obtained should form a clear yellowish liquid distinctly separated from the acid solution beneath it. There should be no black or white sediment in or below the column of fat, and no bubbles or foam on its sur- face. The bottles must be kept warm until the read- ings are made, so that the column of fat will have a sharply defined upper and lower meniscus. When the testing is done in a cold room, it is a good plan to place the bottles in a pail with water of 140° F. be- fore readings are made. The readings should always be made when the fat has a temperature of about 140° -F.; too low results will be obtained if the fat is allowed to cool below 120° F., and too high if readings are taken above 150°. The fat separated in the Babcock test solidifies at about 100° F. If the fat is partly sol- 1The effect of differences in the temperature of the fat on the read- ings obtained will be seen from the following: If 110 and 150° F. be taken as the extreme temperatures at which readings can be made, this difference of 40° I. (22.3° C.) would make a difference in the vol- ume of the fat column obtained in the case of 10 per cent. milk of .00064 x2x22.3=.028544 ec., or .14 per cent., .00064 being the expansion coefficient of pure butter fat per degree Centigrade between 50 and 100° The Babcock Test. air 42. Readings of tests of milk made in steam turbine testers with tightly closed covers which prevent the free escape of exhaust steam (71), will come .2 to .3 per cent. too high if the temperature of the fat is allowed to rise to that of the exhaust steam during the process of whirl- ing. In such cases the test bottles must be allowed to eool to about 140°, by placing them in water of this temperature for a few minutes, before readings are taken.’ A pair of dividers will be found convenient for meas- uring the fat, and the liability of error in reading is decreased by their use. The points of the dividers are placed at the upper and lower limits of the fat column (from a to b in fig. 10). The dividers are now lowered, one point being placed at the zero mark of the scale, and the mark at which the other point touches the scale will show the per cent. of fat in the sample tested. The dividers must be tight in the joint to be of use for this purpose. B.—DISscussION OF THE DETAILS OF THE Bapcock TEST. 43. The main points to be observed as to apparatus and testing materials in order to obtain correct and satisfactory results by this test will now be considered, and such suggestions and help offered as have been found needful from past experience with a great variety of samples of milk, apparatus, and accessories. C. (Zune, Analyse des Beurres, I, 87), and 2, the volume of the fat in ce. contained in 17.6 cc. of 10 per cent. milk. On 5 per cent. milk this extreme difference would therefore be about .07, or nearly .1 of 1%. 1See Wis. Expt. Sta. rep., XVII, p. 76. 38 Testing Milk and Its Products. 1.— GLASSWARE. 44. Test bottles. The test bottles should have a ea- pacity of about 50 ec., or less than two ounces; they should be made of well-annealed glass that will stand sudden changes of temperature without breaking, and should be sufficiently heavy to withstand the maximum centrifugal force to which they are likely to be sub- jected in making tests. This force may, on the average, be not far from 30.65 lbs. (see 66), which is the pres- sure exerted in whirling the bottles filled with milk and acid in a centrifugal machine of 18 inches diameter at a speed of 800 revolutions per minute. When 17.6 ec., or 18 grams of milk (48), are meas- ured into the Babcock test bottle, the scale on the neck of the bottles will show directly the per cent. of fat found in the milk. The scale is graduated from 0 to 10 per cent. 10 per cent. of 18 grams is 1.8 grams. As the specific gravity of pure butter fat (1. e., its weight compared with that of an equal volume of pure water) at the temperature at which the readings are made (about 140° F.), is 0.9, then 1.8 grams of fat will oe- cupy a volume of '-S==2 eubie centimeters. The space between the 0 and 10 per cent. marks on the necks of the test bottles must therefore hold exactly 2 cubic cen- timeters. The scale is divided into 10 equal parts, each part representing one per cent., and each of these is again sub-divided into five equal parts. Each one of the latter divisions therefore represents two-tenths of one per cent. of fat when 17.6 ec. of milk is measured out. The small divisions are sufficiently far apart in most Bab- cock test bottles to make possible the estimation of one- The Babcock Test. 39 tenth, or even five-hundredths, of one per cent. of fat in the samples tested. In the best kinds of Babcock bottles the per cent. marks are complete circles and the half per cent. marks are semi-circles. This greatly aids in making correct readings. As the necks of Babcock test bottles vary in diame- ter, each separate bottle must be calibrated by the manu- facturers; the length of the scale is not, for the reasons given, apt to be the same in different bottles.’ If the figures and lines of the scale become indistinct by use, the black color may be restored by rubbing a soft pencil over the scale, or by the use of a piece of burnt cork after the scale has been rubbed with a little tallow. On wiping the neck with a cloth or a piece of paper the black color will show in the etchings of the glass, making these plainly visible. Special forms of test bottles used in testing cream and skim milk are described under the heads of. cream and skim-milk testing (89, 90, 99). 44a. Eight-per-cent. bottles. Milk test bottles with scale graduated from 0 to 8 per cent. have come into general use of late years, having been adopted in 1911 by the National Dairy Instructors’ Association as ‘‘standard.’’ The specifications for this bottle and other Babeock glassware are given in par. 307. 45. Marking test bottles. Test bottles can now be bought with a small band or portion of their neck or body ground or ‘‘frosted,’’ for numbering the bottles with a lead pencil. Bottles without this ground label can be roughened at any convenient spot by using a wet fine file to roughen the smooth surface of the glass. 40 Testing Milk and Lis Products. There is this objection to the latter method that, unless carefully done, it is apt to weaken the bottles so that they will easily break, and to both methods, that the lead pencil marks: made on such ground labels may be effaced during the test if the bottles are not carefully handled. Small strips of tin or copper with a number stamped thereon are sometimes attached as a collar around the necks of the bottles. They are, however, easily lost, especially when the top of the bottle is slightly broken, or at any rate, are soon corroded so that the numbers can only be seen with difficulty. The best and most permanent label for test bottles is made by scratching a number with a marking diamond on the glass di- ——— rectly above the jelas] scale on the neck of the bottles or by grinding a number on the bottle itself. In ordering an out- fit, or test bottles alone, the oper- === ator may specify = —ZZzEE that the bottles ee mae acid eee are to be marked 1 to 24, or as many as are bought, and the dealer may then put the numbers on with a marking diamond. A careful record should be kept of the number of the bottle into which each particular sample of milk is measured. Mistakes often happen when the operator | uu a ] be The Babcock Test. 4} trusts to his memory for locating the different bottles in which tests are made at the same time. 46. Cleaning test bottles. The fat in the neck of the test bottles must be liquid when these are cleaned. Fic. 13. Apparatus for cleaning test bottles. A, apparatus in posi- tion; the water flows from the reservoir through the iron pipe b into the inverted test bottle d through the brass tube c, screwed into the iron pipe. B shows construction of the rubber support on which the test bottles rest; f, sink. In emptying the acid the bottle should be shaken in order to remove the white residue of sulfate of lime, etc., from the bottom; if the acid is allowed to drain out of the bottle without shaking it, this residue will 42 Testing Milk and Its Products. be found to stick very tenaciously to the bottom of the bottle in the subsequent cleaning with water. A convenient method of emptying test bottles is shown in the illustration (fig. 12). After reading the fat col- umn, the bottles are placed neck down, in the half-inch holes of the board cover of a five-gallon stoneware jar. An oceasional shaking while the liquid is running from the bottles will rinse off the preciptate of sulfate of lime A thorough rinsing with boiling hot water is generally sufficient to remove all grease and dirt, as well as acid solution from the inside of the bottles. The apparatus shown in fig. 13 will be found convenient for this purpose. After the bottles have been rinsed a second time, they may be placed in an inverted posi- tion to drain, on a galvanized iron rack, as shown in fig. 14, where me are nee until needed. The outside = a = of the bottles should ors occasionally be wiped | clean and dry. Etre ee S . 47. The amount of ——1 unseen fat that clings to test bottles. used for testing milk or cream, is generally not sufficient to be noticed in test- ing whole milk, but it plays an important part in test- ing samples of separator skim milk. It may be readily brought to light by making a blank test with clean water in bottles used for testing ordinary milk, which have been cleaned by simply draining the contents and rinsing once or twice with hot water; at the conclusion of the test the operator will generally find that a few lie. 14. Draining rack for test bottles. The Babcock Test. 43 drops of fat will collect in the neck of the bottles, some. times enough to condemn a separator. Boiling hot water will generally clean the grease from glassware for a time, but all test bottles should, in ad- dition, be given an cecasional bath in some weak alkali or other grease-dissolving solution. Persons doing con- siderable milk testing will find it of advantage to pro- vide themselves with a small copper tank, fig. 15, which can be filled with a weak alkali-solution. After having been rinsed with hot water, the test bottles are placed in the hot solution in the tank, where they may be left completely covered with the liquid. If the tank is provided with a small faucet at the bottom, the liquid ean be drawn off when the test bottles are wanted. A tablespoonful of some cleaning pow- - \\ \ der to about two \E== ae = gallons of water T\ ae ae will make a very satisfactory solu- tion; sal soda, Gold Dust, Lewis’ lye or Babbitt’s potash are very efficient for this purpose. The cleansing proper- ties of solutions of any of these sub- .--= stances are in- creased by warm- Hie ane theslquid. The wic@is: Tank for cledine fest bottles. _ 44 : Testing Milk and Its Products. test bottles must be rinsed twice with hot water after they are taken from this bath. An excellent cleaning solution that ean be used for a long time, may be made of one-half pound bichromate of potash to one gallon of sulfuric acid. 47a. An arrangement for cleaning a number of test bottles at the same time is shown in fig. 16.2. IIT shows PP Fic. 16. the number of revolutions per minute = v being as before Diameter Velocity in feet Number of revolutions of wheel, D. per second, v. of wheel per minute. 10 46.84 1074 12 51.31 980 14 55.43 909 16 ~ aeeG 848 18 62.84 800 20 66.24 759 22 69.47 724 24 72.56 : 693 These figures show that a tester, e. g., 24 inches in diameter, will require less than 700 revolutions per minuate for a perfect separation of the fat in Babcock bottles, while a ten-inch tester must have a speed of nearly 1100 revolutions in order to obtain the same result. 08 ‘Testing Milk and Its Products. The speed at which testers of different diameters should be run to effect a complete separation has been calculated by Prof. C. L. Beach in the following manner. The same standard as before is taken, viz., 800 revolutions for an 18-inch tester (radius 9 inches) ; then if a designate the radius of the tester and y the speed required, we have xy —9 X 8007, or / 9X8008 Ue ies ee The figures obtained by the use of this formula are similar to those given in the preceding table. 67. To find the number of turns of the handle corre- » sponding to the number of revolutions made by the wheel, the handle is given one full turn, and the number of times the wheel revolves, is noted. If the wheel has a diameter of 20 inches and revolves 12 times for one turn of the handle, the latter should be turned *3°=63 times a minute (see table), or about once every second, in order to effect a maximum separation of fat. By counting the number of revolutions, watch in hand, and consulting the preceding table, the operator will soon know the speed which must be maintained in case of his particular machine. It is vitally important that the required speed be always kept up; if through care- lessness, worn-out or dry bearings, low steam pressure, etc., the speed is slackened, the results obtained will be too low; it may be a few tenths, or even more than one per cent. Care as to this point is so much the more essential, as the results obtained by too slow whirling may seem to be all right, a clear separation of fat and 1 Private communication. The Babcock Test. 59 good duplicates being often obtained, even when the fat is not completely separated. 68. Ascertaining the necessary speed of testers. ln buying a tester the operator should first of all satisfy himself at what speed the machine must be run to give correct results; the preceding table will serve as a guide on this point. He should measure out a dozen tests of the same sample of milk, and whirl half the number at the speed required for machines of the diameter of his tester. Whirl the other half at a somewhat higher speed. If the averages of the two sets of determinations are the same, within the probable error of the test (say, less than one-tenth of one per cent.), the first whirling was sufficient, as it is believed will generally be the case. If the second set of determinations come higher than the first set, the first whirling was too slow, and a new series of tests of the same sample of milk should be made to ascertain that the speed in the second set of determina- tions was sufficient. This method will test not only the speed required with the particular machine at hand, but will also serve to indicate the correctness of the calibration of the bot- tles. A large number of tests of the same sample of milk made as directed (pouring the milk once or twice previously to taking out a pipetteful for each test) should not vary more than two-tenths of one per cent. at the outside, and in the hands of a skilled operator will generally come within one-tenth of one per cent. If greater discrepancies occur, the test bottles giving too high or too low results should be further examined, and calibrated according to the directions already given (53 et seq.). 60 Testing Milk and Its Products. 69. Hand testers. When only a few tests are made at a time, and at irregular intervals, as in case of dairy- men who test single cows in their herds, a small hand tester answers every purpose. These may be had in sizes from two to twelve bottles. In Pi selecting a particular make of tester tate the dairyman has the choice of a large Babcock hand testers. number of different machines. Most of the first machines placed on the market for this purpose were so cheaply and poorly constructed as to prove very unsat- isfactory after hay- ing been in use for a time. The competi- tion between manu- facturers of dairy supplies and the clamor of dairymen 3 for something cheap, Fic. 21. Type of Babcock hand testers. fully account for this condition of affairs. This ap- plies especially to the early machines made with belts or friction application of power. Hand testers made with cog-geared wheels can be depended on to give the necessary speed when run according to the manufactur- ers’ directions; the earlier machines of this kind were very noisy, but at the present time the best machines on the market are of this type. These are provided with spiral cog-gearing and ball bearings, are strongly made and will run smoothly and with little noise (figs The Babcock Test. 61 20 and 21); in cog-geared machines the bottles are al- ways whirled at the speed which the number of turns made by the crank would indicate. 70. Power testers. For factory purposes, steam tur- bine machines (figs. 22-24) are most satisfactory when well made and well cared for. They should be pro- vided with a_ speed indi- eator and steam gauge, both for the purpose of knowing that sufficient speed is at- tained, and to prevent what may be serious. accidents from a general smash-up, if the turbine ‘‘runs wild’’ by — : turning on too much steam. low skimmed The extent of the adulteration is determined as given below. 127. Calculation of extent of adulteration.’ In the following formulas, percentages found in the control- samples, if such are at hand, are always substituted for the legal standards. a. Skimming.—1. If a sample of milk has been skimmed, the following formula will give the number of pounds of fat abstracted from 100 lbs. of milk: 1Woll, Handbook for mane oan Dairymen, New York, 1907, pp. 267-8. 116 Testing Milk and Its Products. Fat abstracted—legal standard for fat—f, . . (I) f being the per cent. of fat in the suspected sample. 2. The following formula will give the per cent. of fat abstracted, calculated on the total quantity of fat originally found in the milk: £100 ae tees laren aa a b. Watering.—If a sample is watered, the calcula- tion is most conveniently based on the percentage of solids not fat in the milk. The percentage adulteration inay be expressed either on basis of the amount of water present in the adulterated milk, or the amount of water added to the original milk: 1. Per cent. of foreign (extraneous) water in the adul- terated milk =100— See eat a (IIT) S being the per cent. of solids not fat in the suspected sample. Example: A sample of milk contains 7.5 per cent. solids not fat; if the legal standard for solids not fat is 9 per cent., then 100— —1-5*19° —16.7, shows the per cent. of extraneous water in the milk. 2. Watering of milk may also be expressed in per cent. of water added to the original milk, by formula IV: Per cent. of water added to the original milk 100 leg. stand. for sol. not fat a a us A OC ae S In the example given above,**—100—20 per cent of water was added to the original milk. ce. Watering and skimming.—If a sample has been both watered and skimmed, the extent of watering is Babcock Test for other Milk Products. LAG ascertained by means of formula (III) or (IV), ana the fat abstracted found according to the following formula: Per cent. fat abstracted—= leg. stand. for sol. not fat Saal eee Example: A sample of milk contains 2.4 per cent. of fat and 8.1 per cent. solids not fat; then leg. stand. for fat — KEe CV) Extraneous water in milk—100— Fat abstracted=3— °* 5 =33 per pa 100 lbs. of the milk eetied 10 lbs. of extraneous water and .33 Ib. of fat had been skimmed from it. 2S 00 =10 per cent. For methods of detection of other adulterations and of preservatives in dairy products, see Chap. X, 299, et seq. Questions. 1. What is the weight of 1000 cc. of (a) water; (b) skim milk; (c) whole milk; (d) cream testing 30% fat; (e) whey; (f) butter fat? 2. If the sp. gr. of a sample of milk is 1.0325 at 68° F., what is the lactometer reading at 60°? 3. What effect on the sp. gr. has 1.0% solids not fat and 1.0% fat? 4. How can the accuracy of a lactometer be determined? 5. If a sample of milk has a sp. gr. of 1.032 and 13.0% sol- ids, what is the sp. gr. of the milk solids? 6. How can (a) skimmed milk, (b) watered milk, (c) skimmed and watered milk be detected? 7. Give lactometer readings and percentages of fat in sam- ples showing (a) watering, (b) skimming, (¢c) watering and skimming. 8. If one quart of water is added to one quart of milk, what per cent. of water is added, and what per cent. extraneous water does the mixture contain? 118 Testing Milk and Its Products. 9. How many pounds of fat have been removed from 100 pounds of a sample of milk testing 2.6%, and what per cent. of the fat was removed? 10. If a sample of milk contains 7.0% solids not fat, what per cent. water was added and how much extraneous water did the sample contain? 11. What has probably been done to each of the following samples of milk, that were found to contain (a) 7.2 per cent. solids not fat, 2.6 per cent. fat; (b) 9.0 per cent. solids not fat, 2.5 per cent. fat; (c) 6.5 per cent. solids not fat, 2.4% fat? 12. What is the per cent. solids not fat and what is the con- dition of each of the following samples of milk: Lactometer Reading. Per Cent Fat. (a) 32,0286 58°F. 4.0 (b) 33.5) atc oG? -F, Bho (c) 30.0. at (63°. F: BS) (d) 28.0 at 54° F. O85 (e) 27.4 at 69° F. 2.4 CHAPTER VII. TESTING THE ACIDITY OF MILK AND CREAM. 128. Cause of acidity in milk. Even directly after milk is drawn from the udder it will be found to have an acid reaction, when phenolphtalein is used as an in- dicator.. The acidity of fresh milk is not due to the presence of free organic acids in the milk, like lactic or citric acid, but to acid phosphates, and possibly also in part to free carbonic acid gas in the milk or to the acid reaction of casein. Even in case of so-called sweet milk, nearly fresh from the cow, a certain amount of acidity, viz., on the average about .07 per cent., is there- fore found. When the milk is received at the factory it will rarely test less than .10 per cent. of acid, caleu- lated as lactid acid; some patrons bring milk day after day that does not test over .15 per cent. of acid; that of others tests from .20 to .25 per cent., and some lots, although very rarely, will test as high as .3 of one per cent. of acid. It has been found that milk will not usually smell or taste sour or ‘‘turned,’’ until it con- tains .30 to .385 per cent. of acid. 129. The acidity in excess of that found normally in milk as drawn from the udder, is due to other causes than those described. Bacteriological examinations of milk from different sources and of milk of the same origin at different times have shown that there is, roughly speaking, a direct relation between the bacteria found 1Freshly drawn milk shows an amphoteric reaction to litmus, i. e., it colors blue litmus paper red, and red litmus paper faintly blue. 120 Testing Milk and Its Products. in normal milk, and its acidity; the larger the number of bacteria per unit of milk, the higher is, in general, the acidity of the milk. The increase in the acidity of milk on standing is caused by the breaking down of milk sugar into lactic acid through the activi- ties of acid-forming bacteria. Since the bacteria get into the milk through a lack of cleanliness during the milking, or careless handling of the milk after the milking, or both, it follows that an acidity test of new milk will give a good clue to the care bestowed in hand- ling the milk. Such tests will show which patrons take good eare of their milk and which do not wash their cans clean, or their hands and the udders of the cows before milking, and have, in general, dirty ways in milk- ing and caring for the milk. The acidity test is always higher in summer than in winter, and is generally high in the case of milk kept for more than a day (Monday milk), or delivered after a warm, sultry day or night. The bacteria have had a good chance to multiply greatly in such milk, even if it be kept cooled down to 40°-50° F., and as a result considerable quantities of lactic acid have been formed. The determination of the acidity of fresh milk is explained in detail below (147). 130. Method of testing acidity. Methods of meas- uring the acidity or alkalinity of liquids by means of certain chemicals giving characteristic color reactions in the presence of acid or alkaline solutions (so-called volumetric methods of analysis) have been in use for many years in chemical laboratories. They were applied to milk as early as 1872 by Soxhlet,! and the method 1 Jour. f. prakt. Chemie, 1872, p. 6, 19. Testing the Acidity of Milk and Cream. 1 a worked out by Soxhlet and Henkel has since been in general use by European chemists. They measured out 50 ec. of milk to which was added 2 ce. of a 2 per cent. aleoholic solution of phenolphtalein, and this was ti- trated with a one-fourth normal soda solution’ (see below). In this country, Dr. A. G. Manns in 1890 pub- lished the results of work done in the line of testing the acidity of milk and cream,” and the method of pro- cedure and apparatus proposed by him has become known under the name of Manns’ test, and is being advertised as such by dealers in dairy supplies. 131. Manns’ test. The acid in milk or cream is measured by using an alkali solution of a certain strength, with an indicator which shows by a change of color in the milk when all its acid has been neutralized. Any of the alkalies, soda, potash, ammonia, or lime can be used for making the standard solution, but it requires the skill and apparatus of a chemist to prepare it of the proper strength. 2 ; ee Res will cease. The time re- ,_ 8 = Cherie Urtus ya Nw. quired for coagulating the milk is shown di- _ rectly by a scale on the inside wall of the cup (see fig. 49). Fic. 49. The Marschall rennet test. 1 Decker, Cheese Making, Revised ed., 1909 p. 39. CHAP THR. LX. TESTING MILK ON THE FARM. 159. Variations in milk of single cows. The varia- tions in the tests of milk of single cows from milking to milking or from day to day, are greater than many cow-owners suspect. There seems to be no uniformity in this variation, except that the quality of the milk produced generally improves with the progress of the period of lactation; even this may not be noticeable, however, except when the averages of a number of tests made at different stages during the lactation period are compared with each other. When a cow gives her maxi- mum quantity of milk, shortly after calving, the qual- ity of her milk is generally poorer (by one per cent. of fat or less) than when she is drying off. Strippers’ milk is therefore, as a rule, richer in seat than the milk of fresh cows. 160. By testing separately every milking of a number of cows through their whole period of lactation, the results obtained have seemed to warrant the following conclusions in regard to the variations in the test of the milk from single cows, and it is believed that these con- clusions allow of generalization. 1. Some cows yield milk that tests about the same at every milking, and generally give a uniform quantity ~ of milk from day to day. 1Tllinois experiment station, bulletin 24. Testing Milk on the Farm. 143 - : 2. Other cows give milk that varies in an unexplain- able way from one milking to another. Neither the morning nor the evening milking is always the richer, and even if the interval between the two milkings is exactly the same, the quality as well as the quantity of milk produced will vary considerably. Such cows are generally of a nervous, excitable temperament, and are easily affected by changes in feed, drink, or surround: ing conditions. 3. The milk of a sick cow, or of a cow in heat, as a rule, tests higher than when the cow is in normal con- dition; the milk yield generally decreases under such conditions; marked exceptions to this rule have, how- ever, been observed. 4. Half-starved or underfed cows may give a small yield of milk testing higher than when the cows are properly nourished, probably on account of an accom- panying feverish condition of the animal. The milk is, however, more generally of an abnormally low fat con- tent, which may be readily increased to the normal per cent. of fat by liberal feeding. 5. Fat is the most variable constituent of milk, while the solids not fat vary within comparatively narrow limits. The summary of the analyses of more than 2400 samples of American milk calculated by Cooke! shows that while the fat content varies from 3.07 to 6.00 per eent., that of casein and albumen varies only from 2.92 to 4.30 per cent., or less than one and one-half per cent.. 1 Vermont experiment station, report for 1890, p. Yi; Woll’s [land- book for Farmers and Dairymen, Fifth ed., p. 250. 144 Testing Milk and Its Products. and the milk sugar and ash content increases but little (about .69 per cent.) within the range given. 6. A test of only one milking may give a very erro- neous impression of the average quality of a certain cow’s milk. A composite sample (see 179) taken from four or more successive milkings will represent the average quality of the milk which a cow produces at the time of sampling. 161. The variations that may occur in testing the milk of single cows, are illustrated by the following fig- ures obtained in an experiment made at the Illinois ex- periment station,’ in which the milk of each of six cows was weighed and analyzed daily during the whole period of lactation. Among the cows were pure-bred Jerseys, Shorthorns and Holsteins, the cows being from three to eight years of age and varying in weight from 850 to 1350 Ibs. During a period of two months of the year? — the cows were fed a heavy grain ration consisting of twelve Ibs. of corn and cob meal, six lbs. of wheat bran, and six lbs. of linseed meal, per day per head. This sys- tem of feeding was tried for the purpose of increasing, if possible, the richness of the milk. The influence of this heavy grain feed, as well as that of the first pasture grass feed, on the quality and the quantity of the milk produced is shown in the following table, which gives the complete average data for one of the cows (No. 3). The records of the other cows are given in the publica- tion referred to; they were similar to the one here given in so far as variations in quality are concerned. es 1 Bulletin 24. 2See 175. Testing Milk on the Farm. 145 Average results obtained in weighing and testing a cow’s milk daily during one period of lactation. Daily milk Test of | Yield of fat = yield one day’s milk | per day = | Sauce aa oa | MONTH (|2F2/5& |2 |# sees Uf aig easel eo ie o- | Sa Sie Ce a tS AS | Maes a6 4 = |= | 82) 2 | 62] $3 | Be] 65] 4 |e | BF | 4 a ae J ie a )mal| ya a a J | December -_---| 920 || 12.1 | 16.0 | 10.0 3.8 4.9 3.0 46 60 3 Janwary o2._2- OFZ SCOP 14 OF Soe 7 RT 59 76 44 February ----- 103-1624") 17.7 i825.) 3:6) 5.8 | 32 58 84 51 Weare liee = oo 1047 |) 1423" | 16.0: | 1255 3.8 4.7 3.4 54 .61 50 Atirileee. 843. 1054 || 13.8 | 16.5 | 11.5 4.0 5.8 3.0 5d ate 46 Vee ae 1079 || 14.5 | 17.2 | 10.0 3.8 4.6 3.4 5D .70 44 pn Gees 6 os 1103. 121 14.0 | 9.2 a. 9 1 426 re 47 Bs ( 35 Slt lig ee 1180 iS i ea MD Pe? 6.0 4.2 6.2 2.8 39 .60 27 AVeOUS . bac. | 1130 6.4 9.3 ays 4.7 7.9 2-9 30 00 16 162. The average test of this cow’s milk for her whole period of lactation was 3.8 per cent. of fat (i. e., the total quantity of fat produced —totual milk yield X 100) ; twice during this time the milk of the cow tested as high as 5.8 per cent., and once as low as 2.7 per cent. The average weight of milk produced per day by the cow was 14 lbs.; this multiplied by her average test, 3.8, shows that she produced on the average .53 Ib., or about one-half of a pound, of butter fat per day during her lactation period. If, however, her tutter-producing capacity had been judged by the test of her milk for one day only, this test might have been made either on the day when her milk tested 5.8 per cent., or when it was as low as 2.7 per cent. Both of these tests were made in mid-winter when the cow gave about 16 lbs. of milk a day. Multiplying this quantity by .058 gives .93 lb. of fat, and by .027 gives .43 lb. of fat. Either 10 146 Testing Milk and Its Products. result would show the butter fat produced by the cow on certain days, but neither gives a correct record of her actual average daily performance for this lactation period. , A sufficient number and variety of tests of the milk of many cows have been made to prove that there is no definite regularity in the daily variations in the richness of the milk of single cows. The only change in the quality of milk common to all cows is, as stated, the natural increase in fat content as the cows are dry- ing off, and even in this case the improvement in the quality of the milk sometimes does not occur until the milk yield has decreased very materially. 163. Causes of variations in fat content. The qual- ity of a cow’s milk is, as a rule, decidedly influenced by the following conditions: Length of interval between milkings. Change of feed. Change of milkers. Rapidity of milking. Exposure to rain or bad weather. Rough treatment. Unusual excitement or sickness. 164. Disturbances like those enumerated frequently increase the richness of the milk for one, and some- times for several milkings, but a decrease in quality fol- lows during the gradual return to normal conditions, and taken as a whole there is a considerable falling off in the total production of milk and butter fat by the cow, on account of the nervous excitement which she has gone through. Aside from changes due to well- Testing Milk on the Farm. 147 definable causes like those given above, the quality of some cows’ milk will often change considerably without any apparent cause. The dairyman who is in the habit of making tests of the milk of his individual cows at regular intervals will have abundant material for study in the results obtained, and he will soon be able to tell from the tests made, if these are continued for severa! days, whether or not the cows are in a normal healthy condition or have been subjected to excitement or abuse in any way. 165. Number of tests required during a period of lactation in testing cows. The daily records of the six cows referred to on page 142 furnish data for com- paring their total production of milk and butter fat dur- ing one period of lactation, as found from the daily weights and tests of their milk, with the total amount ealeulated from weights and tests made at intervals of 7, 10, 15 or 30 days. The averages of: all results ob- tained with each of the six cows show that weighing and testing the milk of a cow every seventh day gave 98 per cent. of the total milk and butter fat, which according to her daily record was the total product. Tests made one day every two weeks gave 97.6 per cent. of the total milk, and 98.5 per cent. of the total butter fat, and tests made one day per month, or only ten times during the period of lactation, gave 96.4 per cent. of the total milk, and 97 per cent. of the total production of butter fat. 166. The record of one of the cows will show how these calculations are made: It was found from the daily weights and tests that cow No. 1, in one lactation period of 307 days, gave 5,044 Ibs. of milk which con- 148 Testing Milk and Its Froducts. tained 254 lbs. of butter fat. Selecting every thirtieth day of her record as testing day, the total production of milk and fat is shown to be as follows: Production of milk and butter fat per day. | Testing day | Weight of milk | Test of Milk | Yield of butter fat Tubs: Per cent. | Lbs. Noy nan 2 Ese | 20.5 4.7 .96 Decharac ease ee | 18.7 4.6 86 Jani oe eee aly orf 4.9 86 eye Deticepeepaes' 20.0 4.5 .90 Mares os Soo 18.2 4.7 .86 ba oni] ep Reet Ae et Te 19.5 4.4 81 May. 2 ee Se a AE 4.8 .85 dune tse eae iat 5.5 les Sruilyase at pao re 12.2 6.2 76 duly reroll Sass Sesess 3.2 Wee 23 obese sheen ee 160.8 Ibs. eS 7.81 lbs. Average per day_., 16.08 lbs. | 4.85 78 Ib. The average -daily production of the cow, according to the figures given in the preceding table, was about 16 lbs. of milk, containing .78 lb. of butter fat. Multi- plying these figures by 307, the number of days during which the cow was milked, gives 4,912 Ibs. of milk and 240 lbs. of fat. This is 132 Ibs. of milk and 14 lbs. of fat less than the total weights of milk and butter fat, as found by the daily weights and tests, or 2.8 and 5.5 per cent. less, for milk- and fat production, respectively. This is, however, calculated from only ten single weights and tests, while it required over 600 weighings and 300 tests of the milk to obtain the exact amount. Similar calculations from the records of the other cows gave fully as close results, showing that quite sat- Testing Milk on the Farm. 149 isfactory data as to the total production of milk and butter fat of a cow may be obtained by making correct weighings and tests of her full day’s milk once every thirty days. 166a. Official tests of dairy cows. The various ex- periment stations conduct tests of dairy cows for breed- ers and farmers, by which means records of production of milk and butter fat are obtained for periods of 7 or 30 days, or for an entire year. This system of official testing is described in bulletins issued by several sta- tions. 167. When to test a cow. The Vermont experi- ment station for several years made a special study of the question when a cow should be tested in order to give a correct idea of the whole year’s production, when only one or two tests are to be made during the lacta- tion period.?, The results obtained may be briefly sum- marized as follows: a. As to quality of milk produced. If two tests of each cow’s milk are to be made during the same lacta- tion period, it is recommended to take composite sam- ples at the intervals given below. FIRST SAMPLE | SECOND SAMPLE For spring cows, 6 weeks after calving 6%4-T%4 mos. after ealving Morcsommer ‘€ |8 .‘* 6 ‘6 For fall 66 8-10“ a; a: ee ce a a If only one test is to be made, approximately correct results may be obtained by testing the milk during the 1See, e. g., Wis. exp. station bull. 191 and 242; also bull. 226, The Wisconsin Dairy Cow Competition, and research bull. 26, Studies in Dairy Production, published by this station. 2 Sixth report, 1882, p. 106; Ninth report, 1895, p. 176. 150 Testing Milk and Its Products. sixth month from calving, in case of spring cows; dur- ing the third to fifth month in case of summer-calving cows, and during the fifth to seventh month for fall- calving cows. In all cases composite samples of the milk for at least two days should be taken (169). ‘‘The test of a single sample, drawn from a single milking or day, will not of necessity, or indeed usually, give trustworthy results.’’ b. As to quantity of milk produced. The milk may be weighed for two days in the middle of the month, and the entire month’s yield obtained with considerable ; accuracy (barring sickness and drying off), _-by multiplying the sum by a faetor, ac- cording to the number of days in the dif- ferent months, The weighing is_ read- 1 ily done by means of a spring balance, the ‘J hand of which is set back so that the empty 4! pail brings it to zero (fig. 50). If several “qd pails are to be used, they should first be ».| made to weigh the same by putting a little “solder on the lighter pails. Milk scales which weigh and automatically register the yleld of milk from twenty cows have been ic. be Mik Placed on the market, but so far as known scale. have not proved satisfactory. 168. Sampling milk of single cows. In sampling the milk of single cows, all the milk obtained at the milking must be carefully mixed, by pouring it from one vessel to another a few times, or stirring it thor- oughly by means of a dipper moved up and down, as well as horizontally, in the pail or can in which it is Testing Milk on the Farm. 151 held; a sample for testing purposes is then taken at once. A correct sample of a cow’s milk cannot be ob- tained by milking directly into a small bottle from one teat, or by filling the bottle with a little milk from each teat, or by taking some of the first, middle and last milk drawn from the udder. Such samples cannot possibly represent the average quality of the milk of one entire milking, since there is as much difference between the first and the last portions of a milking, as between milk and cream.’ Lack of care in taking a fair sample is the cause of many surprising results obtained in testing the milk of single cows. 169. Composite samples. When a cow is to be tested for milk production she should be milked dry the last milking previous to the day when the test is to be made. The entire quantity of milk obtained at each milking is mixed and sampled separately. On account of the vari- ations in the composition of the milk, a number of tests of successive milkings must be made. As this involves considerable labor, the plan of taking composite samples is preferable; the method of composite sampling and test- ing is explained in detail under the second subdivision of Chapter X (180) ; suffice it here to say that the method followed in the case of single cows’ or herd milk is to take about an ounce of the thoroughly mixed milk of each milking; this is placed in a pint or quart glass jar containing a small quantity of some preservative, prefer- ably about half a gram (8 grains) of powdered potassium bi-chromate. If a number of composite sam- ples of the milk of single cows are taken, each jar should 1 Agricultural Science, 6, pp. 540-42. 152 Testing Milk and Its Products. be labeled with the number or name of the particular cow. Composite tests are generally taken for two or four days or for a week. If continued for a week, the jars will contain at the end of this time a mixture of the milk of fourteen milkings. The composite sample is then carefully mixed by pouring it gently a few times from one jar to another, and is tested in the ordinary man- ner. The result of this test shows the average quality of the milk produced by the cow during the time the milk was sampled. As the amounts as well as the quality of the milk pro- duced by single cows vary somewhat from day to day and from milking to milking, it is desirable in testing single cows, especially when the test includes only a few days, to take a proportionate part (an aliquot) of each milking for the composite test sample. This is easily done by means of a Scovell sampling tube, the use of which is explained in another place (183), or by a 25 ee. pipette divided into ,})ec.; in using the latter appara- tus as many cubic centimeters and tenths of a cubic centimeter of milk are conveniently taken each time for the composite sample as the weight of milk in pounds and tenths of a pound produced by the cow.? 170. Testing warm milk. The opinion is some- times expressed that a considerable error is intro- duced by measuring out milk warm from the cow for the Babcock test, since milk expands on being warmed, and a too small quantity is obtained in this manner. By calculation of the expansion of milk between different temperatures it is found that 1 Decker, Wis. experiment station, report 16, p. 155. Testing Milk on the Farm. 153 1 ec. of milk at 17.5° C. (room temperature) will have a volume of 1.006289 ce. at 37° C. (blood-heat), i. e., an error of less than .03 per cent. is introduced by measuring out milk of ordinary quality at the latter temperature. While the temperature has therefore prac- tically no importance, the air incorporated in the milk during the milking process will introduce an appreci- able error in the testing, and samples of milk should therefore be left for an hour or more after milking be- fore the milk is measured into the test Lottles. By this time the specific gravity of the samples can also be cor- rectly determined (113). 171. Size of the testing sample. Four ounces area sufficient quantity for a sample of milk if it is desired to determine its per cent. of fat only; if the milk is to be tested with a lactometer, when adulteration is sus- pected, about a pint sample is needed. If this sample of milk is put into a bottle and carried or sent away from the farm to be tested, the bottle should be filled with milk clear up to the neck to prevent a partial churning of butter in the sample during transportation (30). 172. Variations in herd milk. While considerable variations in the quality of the milk of single cows are often met with, a mixture of the milk of several cows, or of a whole herd, is comparatively uniform from day to day; the individual differences tend to balance each other so that variations, when they do occur, are less marked than in case of milk of single cows. There are, however, at times marked variations also in the test of herd milk on successive days; the following figures from the dairy tests conducted at the World’s Columbian Ex- 154 Testing Milk and Its Products. position in Chicago in 1893 illustrate the correctness of this statement. The tests included twenty-five Jersey and Guernsey cows each and twenty-four Shorthorn Cows. Tests of herd milk on successive days. Date Jersey Guernsey Shorthorn July 16, 189322225 4.8 per cent. | 4.6 per cent. | 3.8 per cent. July 270189355525 Dele e eA 4.5 te 3.8 ge July ie, ebegos === 4.7 “i 4.4 = 3.8 Nee July 19, V893i22= 4.6 e 4.6 hy 3.7 ee July 20,-1893- 227. 5.0 Be 4.5 mn 3.8 ae On July 17, 1893, the mixed milk of the Jersey cows tested two-tenths of one per cent. higher than on the preceding day; the Guernsey herd milk tested one-tenth of one per cent. lower, while the Shorthorn milk did not change in composition; comparing the tests on July 19 and 20, we find that the Jersey and Shorthorn milk tested four-tenths and one-tenth of one per cent. higher, respectively, on the latter day than on the former, and the Guernsey milk tested one-tenth of one per cent. lower. There was no change in the feed of the cows or in the method of handling them on these days. 173. Ranges in variations of herd milk. According to Fleischmann,' the composition of herd milk will vary on single days from the average values for the year, expressed in per cent. of the latter, as follows: The specific gravity (expressed in degrees) may go above or below the yearly average by more than 10 per cent. The per cent. of fat may go above or below the yearly aver- age by more than 30 per cent. 1 Book of the Dairy, p. 32. Testing the Purity of Milk. 155 The per cent. of total solids may go above or below the yearly average by more than 14 per cent. The per cent. of solids not fat may go above or below the yearly average by more than 10 per cent. To illustrate, if the average test of a herd during a whole period of lactation is 4.0 per cent., the test on a single day may exceed 4.0+ ,%0, X4.0=5.2, or may go below 2.8 per cent. (viz., 4.0— 0, 4.0); if the average specific gravity is 1.031 (lacto- meter degrees, 31)' the specific gravity of the milk on a single day may vary between 1.0279 and 1.0341 (31+ oo; X31—=34.1; ol— 0 X31=27.9). 174. Influence of heavy grain-feeding on the qual- ity of milk. If cows are not half-starved or underfed, an increase in the feeding ration will not materially change the richness of the milk produced; this has been shown by numerous careful feeding experiments con- ducted under a great variety of conditions and in many countries. Good dairy cows will almost invariably give more milk when their rations are increased, so long as they are not overfed, but the milk will remain of about the same quality after the first few days are passed as before this time, provided the cows are in good health and under normal conditions. Any change in the feed of cows will usually bring about an immediate change in the fat content of the milk, as a rule increasing it to some extent, but in the course of a few days, when the cows have become accustomed to their new feed, the fat content will again return to its normal amount. 175. The records of the cows included in the feeding experiment at the Illinois station, to which reference has been made on p. 144, furnish illustrations as to the effect of heavy feeding on the quality of milk. The 1See page 103. 156 Testing Milk and Its Products. feed, as well as the milk of the cows, was weighed each day of the experiment. During the month of December each cow was fed a daily ration consisting of 10 lbs. of timothy hay, 20 lbs. of corn silage and 2 lbs. of oil meal; the table on p. 145 shows that cow No. 3 produced on this feed an average of 12.1 lbs. of milk, testing 3.8 per cent. of fat. In January the grain feed was gradually increased until the ration consisted of 12 lbs. of timothy hay, 8 lbs. of corn and cob meal, 4 lbs. of wheat bran, and 4 lbs. of oil meal. Al] the cows gained in milk on this feed; cow No. 3 thus gave an average of 4 lbs. more milk per day in January than in December, but the average test of her milk was 3.7 per cent., or one-tenth of one per cent. lower than during the preceding month. The heavy grain-feeding was continued through Febru- ary and March, when it reached 12 lbs. of timothy hay, 12 lbs. of corn and cob meal, 6 lbs. of wheat bran and 6 lbs. of oil meal per day. The records show that the flow of milk kept up to 16 lbs. per day in February in case of this cow, but fell to 14 lbs. in March and April, the average test of the milk being, in February 3.6, in March 3.8, and in April 4.0 per cent. The milk was, therefore, somewhat richer in April than in December, but not more so than is found normally, owing to the progress of the period of lactation. 176. Influence of pasture on the quality of milk. On May 1, the cows were given luxuriant pasture feed and no grain; a slight increase in the average amount of milk produced per day followed, with a reduction in the test, this being 3.8 per cent., the same as in De- cember. Testing Milk on the Farm. 157 During all these changes of feed there was, therefore, not much change in the richness of the milk, while the flow of milk was increased by the heavy grain feeding for several months, as well as by the change from grain- feeding in the barn to pasture feed with no grain.1 As a general rule, the test of the milk will be increased by a few tenths of a per cent. during the first couple of weeks after the cows have been turned out to pasture in the spring. The increase is perhaps due as much to the stimulating influence of out-door life after the con- finement in the stable during the winter and spring, as to the change in the feed of the cows. After a brief period the milk will again change back to its normal fat content. 177. The increase which has often been observed in the amount of butter produced by a cow, as a result of a change in feed, doubtless as a rule comes from the fact that more, but not richer milk is produced. The quality of milk which a cow produces is as natural to her as is the color of her hair and is not materially changed by any special system of normal feeding.” 1¥For further data on this point, see Cornell (N. Y.) exp. sta. bulle- tins 138, 22, 36 and 49; N. D. exp. sta., bull. 16; Kansas exp. sta., re- port, 1888; Hoard’s Dairyman, 1896, pp. 924-5; W. Va. exp. sta., b. 109. 2 On this point numerous discussions have taken place in the past in the agricultural press of this and foreign countries, and the subject has been under debate at nearly every gathering of farmers where feed- ing problems have been considered. Many farmers are firm in their be- licf that butter fat can be ‘‘fed into” the milk of a cow, and would take exception to the conclusion drawn in the preceding. The results of careful investigations by our best dairy authorities point conclusively, however, in the direction stated, and the evidence on this point is over- whelmingly against the opinion that the fat content of the milk can be materially and for any length of time increased by changes in the sys- tem of feeding. The most conclusive evidence in this line is perhaps 158 Testing Milk and Its Products. 178. Method of improving the quality of milk. The quality of the milk produced by a herd can gener- ally be improved by selection and breeding, i. e., by dis- posing of the cows giving poor milk, say below 3 per cent. of fat, and by breeding to a pure-bred bull of a strain that is known to produce rich milk. This method cannot work wonders in a day, or even in a year, but it is the only certain way we have of improving the qual- ity of the milk produced by our cows. It may be well in this connection to call attention to the fact that the quality of the milk which a cow pro- duces is only one phase of the question; the quantity is another, and an equally important one. Much less dis- satisfaction and complaint about low tests among pat- rons of creameries and cheese factories would arise if this fact was more generally kept in mind. A cow giv- ing 3 per cent. milk should not be condemned because her milk does not test 5 per cent.; she may give twice as much milk per day as a 5 per cent cow, and will therefore produce considerably more butter fat. The point whether or not a cow is a persistent milker is also of primary importance; a production of 300 lbs. of but- ter fat during a whole period of lactation is a rather high dairy standard, but one reached by many herds, the Danish co-operative cow-feeding experiments, conducted during the nineties with over 2,000 cows in all. The conclusion arrived at by the Copenhagen experiment station, under whose direction the experiments have been conducted, is: that the changes of feed made in the different lots of cows included on the experiments had practically no influence on the chemical composition (the fat content) of the milk produced. In these experiments grain feeds were fed against roots, oil cake, wheat bran or shorts; grain and oil cake were furthermore fed against roots, and roots were given as an additional feed to the standard rations tried,—in all case~ with practically negative results so far as changes in the fat contents of the milk produced are concerned. Testing Milk on the Farm. 159 as the average for all mature cows in the herd. It should be remembered that a high production of but- ter fat in the course of the whole period of lactation is of more importance than a very high test. Questions. 1. How does the test of the milk yielded by a cow generally change with the advance of the period of lactation? 2. Mention at least six causes of variations in the test of a cow’s milk. 3. How is an accurate sample taken of a cow’s milk? 4, Between which limits is the test of milk of single cows and of a herd likely to vary? 5. Will it introduce any error in the test of a cow’s milk to measure out the sample directly after milking?If so, how much? 6. How many times should the milk of a cow be weighed and tested to calculate the total production of milk and butter fat by the cow during a whole period of lactation? 7. What is an official test of a cow? 8. How does the test, as a general rule, change during the first couple of weeks after the cows are let out on pasture in the the spring? 9. How do changes in the feed of a cow influence the quan. tity and the quality of her milk? CHAPTER X. COMPOSITE SAMPLES OF MILK. 179. Shortly after milk testing had been introduced to some extent in creameries and cheese factories, it was suggested by Patrick, then of the lowa experiment sta- creat saving in la \ tion,! that a Fie. 51. Taking test samples at in-take. bor, without affecting the accuracy of the results, could be ob- tained by testing a mixture of the daily samples of milk from one source, instead of each one of these samples. Such a mix- ture is called a com- posite sample. The usual methods of tak- ing such samples at ereameries and cheese factories are as fol- lows: 180. Methods of taking composite samples. a. Use of tin dipper. Either pint or quart fruit jars, or milk bot- tles provided with a cover, are used for receiving the daily samples. One of these jars is supplied for each 1 Bulletin 9, May 1890. Composite Samples of Milk. 161 patron of the factory and is labeled with his name or number. A small quantity of preservative (bi-chromate of potash, corrosive sublimate, ete., see 190) is added to each jar; these are placed on shelves or somewhere within easy reach of the operator who inspects and weighs the milk as it is received at the factory. When all the milk delivered by a patron is poured into the weighing can and weighed, a small portion thereof, usually about an ounce, is put into the jar labeled with the name or number of the patron. The samples are conveniently taken by means of a small tin dipper hold- ing about an ounce. This sampling is continued for a week, ten days, or sometimes two weeks, a portion of each patron’s milk being added to his particular jar every time he delivers milk. A test of these composite samples takes the place of separate daily tests and gives information regarding the average quality of the milk delivered by each patron during the period of sampling. The weight of butter fat which each patron brought to the factory in his milk during this time, is obtained by multiplying the total weight of milk delivered dur- ing the sampling period by the test of the composite sample, dividing the product by 100. 181. This method of taking composite samples has been proved to be practically correct. It is absolutely correct only when the same weight of milk is delivered daily by the patron. If this is not the case, the size of the various small samples should bear a definite relation to the milk delivered; one sixteen-hundredth, or one two-thousandth of the amount of milk furnished should, for instance, be taken for the composite sample from il 162 Testing Milk and Its Products. each lot of milk. This can easily be done by means of special sampling devices (see 182 et seq.). As the quan- tities of the milk delivered from day to day by each patron vary but little, perhaps not exceeding 10 per cent. of the milk delivered, the error introduced by taking a uniform sample, e. g., an ounce of milk, each time is, however, small and it may not be necessary to take cognizance of it in factory work. This method of composite sampling described is quite generally adopted in separator creameries and cheese factories, where the payment for the milk is based on its quality. In order to obtain reliable results by composite sam- pling it is essential that each lot of milk sampled shall be sweet and in good condition, containing no lumps of eurdled milk or butter granules. The milk should of course always be evenly mixed before the sample is taken. 182. b. Drip sample. Composite samples are some- times taken at creameries and cheese factories by col- lecting in a small dish the milk that drips through a fine hole in the bottom of the conductor spout through which the milk runs from the weighing can to the re- ceiving vat or tank. A small portion of the drip col- lected each day is placed in the composite sample jar, or the quantity of drip is regulated so that all of it may be taken. In the latter case the. quantity of milk delivered will enter into the composite sampling as well as its quality and the sample from, say 200 lbs. of milk, will be twice as large as the sample from 100 lbs. of milk. Where it is desired to vary the size of samples accord- ing to the quantity of milk delivered from day to day, Composite Samples of Mik. 163 it is necessary to adopt the method of collecting drip samples just explained, or to make use of special sam- pling devices, like the ‘‘milk thief,’’ the Scovell, Equity, McKay, and Michels sampling tubes... The principle of these tubes is the same, and it will be sufficient to describe here only a few of them. 183. c. The Scovell sampling tube. This convenient device for sampling milk’ (fig. 52) consists of a drawn copper or brass tube, one- half to one inch in diameter; it is open at both ends, the lower end sliding snugly in a cap pro- vided with three elliptical openings at the side, through which the milk is admitted. The milk to be sampled is poured into a cylindrical pail, or the factory weighing can, and the tube, with the cap set so that the apertures are left open, is lowered into the milk until it touches the bottom of the can. The tube will be filled in- stantly to the level of the milk in the can and is then pushed down against the bottom of the ean, thereby closing the apertures of the cap Rt and confining within the tube a column of milk Scovell representing exactly the quality of the milk sampling in the can and forming an aliquot part thereof. The milk in the sampling tube is then emptied into the composite sample jar by turning the tube ‘upside. down. 1A recent Wisconsin ise (Chap. 99, awe of 1907) proves that in sampling cream or milk from which composite tests are to be made to determine the per cent of butter fat therein, no such sampling shall be lawful, unless a sample be taken from each weighing, and the quantity thus used shall be proportioned to the total weight of cream or milk tested. 2 Kentucky experiment station. Sth report, pp. xxvi-xxvii. 164 Testing Milk and Its Products. 184. If the diameter of the sampling pail used is 8 inches, and that of the sampling tube 14 inch, the quan- tity of milk secured in the tube will always stand in the ratio to that of the milk in the pail, of (14)? to 8, that is, as 1 to 256, no matter how much or how little milk there is in the pail, the sample will represent 34; part of the milk. For composite sampling of the milk of single cows, this proportion will prove about right; if more milk is wanted for a sub-sample, dip twice, or pour the milk to be sampled into a can of smaller diam- eter. If the mixed milk from a number of cows is to be sampled, a wider sampling can may be used. By ad- justing the diameter of the tube or the can, any de- sired proportion of milk can be obtained in the sample. For factory sampling, with a weighing can 26 inches in diameter, a tube three-quarters of an inch in diameter will be found of proper dimensions. In using these tubes, the milk or cream must in all eases be in cylindrical cans when the sample is drawn. The sampling tube will furnish a correct sample of the milk in the can, even if this has been left standing for some time; it is better, however, to take out the sample soon after the milk has been poured into the can, as the possible error of cream adhering to the sides of the sampling tube is then avoided. 185. The accuracy of the sampling of milk by means of the Scovell tube was proved beyond dispute in the breed tests conducted at the World’s Columbian Expo- ‘The contents of a cylinder are represented by the formula 7 r2h, r being the radius of the cylinder, and h its height. The relation be- tween two cylinders of the same height, the radii of which are R and r, is therefore as JR*h to Jr2h, or as R? to r?, Composite Samples of Milk. 165 sition in 1893, in which tests this method was adopted for sampling the milk produced by the single cows and the different herds... The data obtained in these breed tests also furnish abundant proof of the accuracy of the Babcock test. 186. Accuracy of the described methods of sam- pling. An experiment made at the Wisconsin Dairy School may here be eited, showing that concordant re- sults will be obtained by the use of the drip sa:upling method and the Scovell tube. Two composite samples were taken from fifty different lots of milk, amounting to about 6,000 lbs. in the aggregate. One sample was taken of the drip from a hole in the conductor spout through which the milk passed from the weighing can; the other was taken from the weighing can by means of a Scovell sampling tube. The following percentages of fat were found in each of these samples :* Se Gravimetric | Babcock test analysis 4.0 per cent. | 4.04 per cent. 4.0 per cent. | 4.06 per cent. Drip composite sample..__-.---- Scovell tube composite sample_--- 187. d. The McKay sampler (fig. 53), constructed by Professor G. L. McKay, formerly of Iowa experiment station, consists of two nickel-plated brass tubes that telescope one within the other; both have a milled’ slot so made that when the handles stand together the slot is open; by turning the handles at right angles the 1Kentucky experiment station, 8th report, pp. xxx-xxxi. Another form of a milk sampling tube in use at the Iowa experiment station was described and illustrated by Mr. Eckles in Lreeder’s Gazette, May 19. 1897. 2See also 199 et seq. 166 Testing Milk and lts Products. =>Slot is closed, ‘The sampler is made in two lengths, 21 and 18 inches, and has been found very convenient for sampling either milk or cream. 187a. e. Michels’ cream-sam- pling tube consists of a modified Seovell sampler in a tin jacket. It was constructed by Professor John Michels, late of North Carolina agri- cultural college. This sampler ren- t i H ; ; ders possible an accurate and rapid sampling of any cream, regardless of its richness and acidity, without stirring the cream. 188. f. Composite sampling with a ‘“‘one-third saimple pipette.’’ Milk is sometimes sampled directly from the weighing can into the Babcock test bottle by means of a pipette hold- ing 5.87 ce., which is one- “lina third the size of the regu- i lar pipette. This quantity is measured into the test bottle from three successive lots of milk from the same patron and the test then made in the ordinary man- ‘ner. In this way one test shows the average composi- tion of the milk delivered during three successive days or deliveries. When this method is adopted, as many test bottles are provided as Fie. 53. The McKay sampler. il i Ite. 55. Test-bottle rack for use in there are patrons; there is no creameries and cheese factories. = Composite Samples of Milk. 167 need of using any preservatives for milk in this case. Fig. 55 shows a convenient rack for holding the test bottles used in com- posite sampling with a ‘‘one-third sample pipette.’’ Accurate results can be obtained by this method of sampling, if care is taken in measuring out the milk, and if it is not frozen or contains lumps of cream. It is doubtful if the method has any advantage over the usual method of composite sampling. If milk is delivered daily and each lot is sampled with the one-third pipette, twice or three times the number of tests are required as when composite samples are taken in jars and tested once every week or ten days. This method furthermore takes a little more time in the daily sampling than the other, as the quantity of milk must be measured out accurately each time. If a test bottle is accidently broken or some milk spilled, the opportunity of ascer- taining the fat content of the milk delivered during the three days is lost; if a similar accident should occur in testing com- posite samples collected in jars, another test can readily be made. PRESERVATIVES FOR COMPOSITE SAMPLES. ' 189. When milk is kept for any length of time under ordinary conditions, it will soon turn sour and become loppered, and further decomposition shortly sets in, which renders the sampling of the milk both difficult and unsatisfactory (19). The period during which milk will remain in an apparently sweet or fresh condition varies with the temperature at which it is kept, and with the cleanliness of the milk. It will not generally remain sweet longer than two days at the outside, at ordinary summer or room temperature. In order to preserve composite samples of milk in a proper condition for testing, some chemical which will check or prevent the fermentation of the milk must be added to it. A number of substances have been pro- posed for this purpose. 168 Testing Milk and Its Products. 190. Bi-chromate of potash. ‘This preservative is preferred by many because it is relatively harmless, cheap and efficient. The bi-chromate method for pre- serving samples of milk was proposed by Mr. J. A. Alen, city chemist of Gothenburg, Sweden, in 1892,' and has been generally adopted in dairy regions in this country and abroad. While not perfectly harmless, the bi-chromate is not a violent poison like other chemicals proposed for this purpose, and no accidents are liable to result from its use. 191. The quantity of bi-chromate necessary for pre- serving half a pint to a pint of milk for a period of one or two weeks is about one-half gram (nearly 8 grains), about one-half as much as ean be placed on a dime. According to Winton and Ogden,’ a .22-inch pistol cartridge shell 14 inch long, or a .32-inch caliber shell 1/ inch long, when loosely filled, will hold enough pow- dered bi-chromate to preserve 14 pint, and a .32-inch caliber shell 14 inch long will hold enough to preserve one pint. These shells may be conveniently handled by soldering to them a piece of stiff wire which serves as a handle. The amount of bi-chromate placed in each composite sample jar would fill about half the space representing one per cent. in the neck of a Bab- cock milk test bottle. 192. The first portions of milk added to the com- posite sample jars containing the specified amount of bi-chromate will be colored almost red, but as more 1 Biedermann’s Centralblatt, 1892, p. 549. 2 Connecticut. experiment station, report for 1884, p. 222 Composite Samples of Miuk. 169 milk is added day by day, its color will become lighter yellow. The complete sample should have a light straw color; such samples are most easily mixed with acid when tested. If more bi-chromate is used, the solution of the casein in the acid is rendered difficult and re- quires persistent shaking. Bi-chromate can be bought at drug stores or from dairy supply dealers at about 30 cents a pound. Powdered bi-chromate of potash should be ordered, and not crystals, as the latter dissolve only slowly in the milk. Bi-chromate tablets containing the correct quantity of preservative for a quart or pint sam- ple have also been placed on the market and will be found convenient. 193. Corrosive sublimate tablets for composite samples. During late years corrosive sublimate tablets have come into general use in factories. These contain mereurie chlorid with anilin color (rosanilin).t. The coloring matter is added to give a rose color to the sam- ple preserved, thus showing that the milk is not fit for consumption; the bi-chromate giving naturally a yellow eolor to the milk, renders unnecessary the addition of any special coloring matter. Compounds containing corrosive sublimate are violent poisons and must always be handled with the greatest care, lest they get into the hands of children or persons not familiar with their poisonous properties; they will preserve the milk longer than bi-chromate when applied in sufficient quantities. Among other substances recommended for use in but- ter or cheese factories as milk preservatives for com- 1Towa experiment station, bulletins 9, 11, 32. 170 Testing Milk and Lts Products. posite samples may be mentioned formaldehyde, boracic- acid compounds, chloroform, carbon bi-sulfid,* copper ammonium sulfate, sodium fluorid and ammonia glycerin (sporietO3L). 194. Care of composite samples. The composite sample jars should be kept covered to prevent loss by evaporation, and in a cool, dark place, or at least out of direct sunlight when bi-chromate of potash is used as a preservative; the chromic acid formed by the re- ducing influence of light on chromate solutions pro- duces a leathery cream which it is difficult to dissolve in sulfuric acid. A coating of white shellac has been suggested to pro- tect the labels of the composite sample jars. The shel- lac is applied after the names of the patrons have been written on the labels, and when these have been put on the jars. Gummed labels, 1x214 inches, answer this purpose well. Numbers are sometimes ground on the sample jar or stamped on brass tags attached to the jars by a wire. In keeping the milk from day to day, care should be taken that the cream forming on the milk does not stick to the sides of the jars in patches above the level of the’ milk. Unless the daily handling of the jars and the addition of fresh portions of milk be done carefully, the cream will become lumpy and will dry on the sides of the jars. In some cases it is nearly impossible to evenly distribute this dried cream through the entire sample at testing time so as to make the composite 1 Delaware experiment station, eighth report, 1896, which also see for trials with a large number of different preservatives. Composite Samples of Milk. 171 sample a true representative of the different lots of milk from which it has been taken. 195. Every time a new portion of milk is added to the jar this should be given a gentle horizontal rotary motion, thereby mixing the cream already formed in the jar with the milk and loosening the cream stick- ing to its side. This manipulation also prevents the surface of the milk from becoming covered with a layer of partially dried leathery cream. Composite samples having patches of dried cream on the inside of the jar are the result of carelessness or ignorance on the part of the operator. If proper at- tention is given to the daily handling of the composite - samples, the cream formed in the jars can again be evenly mixed with the milk without difficulty. 196. Fallacy of averaging percentages. A composite sample of milk should represent the average quality of the various lots of milk of which it is made up. This will be true if a definite aliquot portion or fraction of the different lots of milk is taken. If the weights of, say ten different lots of milk, are added together and the sum divided by ten, the quotient will represent the average weight per lot of milk, but an average of the tests of the different lots obtained in this way may not be the correct average test of the entire quantity of milk. The accuracy of such an average figure will de- pend on the uniformity in the composition and weights of the ten lots of milk. When there is no uniformity, the weights of the different lots of milk as well as their tests must be considered. The following example will illustrate the difference between the arithmetical aver- 172 Testing Milk and Its Products. age of a number of single tests and the true average test of the various lots. Methods of calculating average percentages. I. Milk varying in weights | Tl. Milk of uniform weights and tests. and tests. penchant Hees Ba a ener = a ie ese all ae me Lot 2 | o¢ aa || Lot = S oe 28 =a Salem 5 | SH Slee =O iS) ie) - =e) io) lbs | per ct. | lbs lbs per ct lbs Tipe ene rs 120 P50 = 4:2 [ae 250 428 Uy SOES Ae ake eT Al 570 5.0 28.5 i (Fare eee eee a | 220 4.0 9.0 1 El fl PS ceo ata 360 Bae 18.7 1) Gl ee ees 240 4.3 10.3 1 AGS ney Be i 8. 5D Sc Ossy PAG a NS eee 238 4.1 9.7 Wate Se 82 4.0 Pa OMA Sie Ve spe ee a Sas 234 4.4 10.3 Motates:<5. sR ydee eae 56: 2°|| y'Fotalces Petree feaccm - 49.8 Average..| 237 | 4.14 | 11.24 Average...| 237 | 4.20 | 10.0 | | | } True aver- | | || True average | age test. --| ei oe GW SCs we mic ss | test 23 | fae tess 40 ea eee | | | *56.2 100 749.8100 SS SB =4.22 1187 1187 197. The figures given in the table show that when the different lots of milk vary in test and weight, as in the first case, the correct average test of the 1187 lbs. of milk is not found by dividing the sum of these tests by five, which would give 4.14 per cent.; but by divid- ing 56.2 (the total amount of fat in the mixed milk) by 1187 (the total amount of milk), which is 4.73; this is the correct average test of the mixed milk made up of the five different lots. In the second ease, the variations in both the weights of the different lots of milk and their tests, are com- paratively small, and both methods of calculation give therefore practically the same average test; but also in this case, the correct average test is found by dividing Composite Samples of Milk. 173 the total amount of fat by the total quantity of milk, making 4.22 per cent., instead of 4.20 per cent., which is the arithmetical mean of the five tests. The quantities © of milk in the various lots do not enter into the calcula- tion of the latter.’ 198. The second example represents more nearly than the first one the actual conditions met with at creameries and cheese factories. As a rule, the mixed milk from a herd of cows does not vary more in total weight or tests, within a short period of time like one - to two weeks, than the figures given in this example. On account of this fact, samples taken, for instance, with a small dipper may give satisfactory results to all parties concerned. If the different lots of milk varied in weight and test from day to day, as shown in the first case, it would be necessary to use a ‘‘milk thief’’ or one of the sampling tubes for taking the composite samples; the size of each of the samples taken would then represent an exact aliquot portion of the various lots of milk (182). 199. A patron’s dilemma. The following incident will fur- ther explain the difficulties met with in calculating average tests of different lots of milk. The weekly composite sample of the milk supplied by a cream- ery patron from his herd of 21 cows tested 4.0 per cent. fat. One day the farmer brought to the creamery a sample of the morning’s milk from cach of his cows, and had them tested; after adding the tests together and dividing the sum by 21, he obtained an average figure of 5.1 per cent. of fat. From this he concluded that the average test of the milk from his cows 1In the experiment given on p. 148, the arithmetical mean of the tests is 5.15 per cent., while the true average fat content of milk is 4.85 per cent. 174 Testing Milk and Its Products. ought to be 5.1, instead of 4.0, and naturally asked for an ex- planation. The first thing done was to show him that while 5.1 was the ‘ gorrect average of the figures representing the tests of his twenty-one cows, it was not a correct average test of the mixed milk from all his cows, as he had not considered, in calculating this average, the quantities of milk yielded by each cow; the following illustration was used: Cow No. 1, yield 25 lbs. of milk, test 3.6 per cent, =0.9 Ib. of butter fat. Cow No. 2, yield 61bs. of milk, test 5.0 per cent.=0.3 lb. of butter fat. Totally sss 31 lbs. 2)8.6 1.2 Ibs. 4.3 per cent. The two cows gave 31 lbs. of milk containing 1.2 lbs. of fat; the test of the mixed milk would therefore not be 4.3 per cent. C="), but 1 SAIN =3.87 per cent. If the fat in the mixed milk was calculated by the average figure 4.3 per cent., 1.33 Ibs. of fat would be obtained, i. e., 0.13 Ib. more than the cows pro- duced. In order to further demonstrate the actual composition of the mixed milk of the twenty-one cows, the milk of each cow was weighed and tested at each of the two milkings of one day. The weights and tests showed that the cows produced the following total number of pounds of milk and of fat: Morning milking, 113.3 Ibs. of milk, containing 5.17 lbs. of fat. Night milking, 130.9 lbs. of milk, containing 4.98 lbs. of fat. The morning milk therefore contained sae of fat, and the night milk, = <0 —3.80 per cent. of fat. The sum of the morning and night milkings gave: milk, 244.2 Ibs., fat 10.15 lbs. The mixed morning and night milk, there- 10.15% 100 244.2 average test of the morning and night milkings of these twenty- one cows, as found by weighing and testing separately the milk of each cow at both milkings. The total milk was strained into a large can at the farm, both in the morning and in the evening. A sample of the mixed milk was in each case taken with a long-handled dipper as soon as the milkings were finished. When the cans of milk were deliv- 4.56 per cent. fore, contained =4.1 per cent. of fat. This is the true Composite Samples of Milk. 175 ered at the creamery, a sample of each was taken with a Scovell sampling tube. The tests of these four samples are given below, together with the results of the individual tests: Morning Milk Night Milk Sample taken at the farm, with dip- BEE eee aa eee eS ee ae 4.4 per cent. |3.8 per cent. Sample taken at creamery with Sco- MERI eo LN ed 4.5 . 3.7 ae Caleulated from weights and tests of lke “trom-each Cows 2. ok | 4.5 xs 3.8 = The figures given show that practically uniform tests were ob- tained by the different methods of sampling. Questions. 1. What is a composite sample of milk? 2. Describe the proper care of composite samples. 3. Give an example showing that composite samples of milk may be inaccurate when taken with a small dipper. 4. Describe the construction of the following methods of sam- pling milk or cream, by (a) drip sample, (b) the Scovell, (ce) the McKay, and (d) the Michels’ sampling tubes. 5. What is the purpose of adding preservatives to milk or cream samples? Mention the more common preservatives used and quantities to be add j. CHAPTER XI. CREAM TESTING AT CREAMERIES. 200. The cream delivered at gathered-cream factories is now tested by the Babcock test in many localities, and this has been adopted as a basis of paying for the cream in the same manner as milk is paid for at separator ereameries. It has been found to be more satisfactory to both cream buyer and seller than either the oil-test churn or the space (or gauge) systems which were pre- viously used for this purpose. The details of the application of the Babcock test to the practical work at cream-gathering creameries have been carefully investigated by Winton and Ogden in Connecticut,! Bartlett in Maine,” and Lindsey in Massa- chusetts,? and we also owe to the labors of these chem- ists much information concerning the present workings of other systems of paying for the cream delivered at creameries. 201. The space system. Numerous tests have shown that one space or gauge of cream does not contain a definite, uniform amount of fat. In over 100 compari- sons made by Winton it was found that one space of cream‘ contained from .072 to .170 lb. of butter fat, or 1Conn. experiment station (New Haven), bull. 108 and 119; report 1894, pp. 214-244. 2Maine experiment station, bull. 3 and 4 (S. S.) 8 Hatch experiment station, report 1894, pp. 92-103; 1895, pp. 67-70. 4The espace is the volume of a cylinder, 81% inches in diameter and 19 of an inch high. The number of spaces in each can of milk is read off before skimming by means of a scale marked on a strip of glass In the side of the can (Conn. exp. sta., bull. 119). Cream Testing at Creamerves. alert on the average .13 lb., and the number of spaces re- quired to make one pound of butter varied from 5.01 to 11.72. It is also claimed that in the winter season when the cream is gathered at long intervals, like once a week, it is necessary for the buyer to accept the seller’s state- ment of the record of the number of cream spaces which he furnishes, since the cream cannot be left in the creaming’ can for so long a time. These objections to the space system apply only to the method of paying for the cream, and not to the manner in which the cream is obtained. 202. The oil-test churn. As stated in the introduc- tion, the otl-test churn (fig. 56) has been used quite ex- tensively among gath- ered-cream factories; this system is based on the number of inches of cream which the various patrons deliver to the factory; a creamery inch is the quantity of cream which will fill a can twelve inches wide, one inch high; it contains 113 cubic inches.’ This quantity was supposed to make one pound of butter. In using this method the driver pours the patron’s eream into his 12-inch gathering pail, measures it with Fic. 56. The oil-test churn. 1A layer of two inches in an 8-inch pail contains 100.531 cubic inches, two inches in a 8%-inch pail 110.18 cubic inches, and two inches in a 8%-inch pail 113.49 cubic inches. 12 178 Testing Milk and Its Products. his rule and records the depth of the cream in the can, in inches and tenths of an inch. The cream is then stirred thoroughly with a ladle or a stout dipper, and sampled by filling a test tube to the graduation mark by means of a small conical dipper provided with a UD A driver’s case contains either two or three ‘‘eards,’’ holding fifteen test tubes each (see fig. 57). The tubes as filled are placed in the case and the corresponding num- = ber in each instance re- y as “iO corded in front of the ij x Mh oN CARD DRIVERS CASE, ‘ patron’s name, together = * geese “w!) with the mnuinber of i inches of cream fur- : nished by him. Wie. 57. Cream-gatherer’s On the arrival at the args ene ereamery the tin cards holding the tubes are placed in a vessel filled with water of the churning temperature (say, 60° in summer and 65° to 70° in winter). When ready for churning they are placed in the oil-test churn (fig. 56), the cover of the churn put on, and the samples of cream churned to butter. On the completion of the churning, the cards are transferred to water of 175-190° Fahr., where they are left for at least ten minutes to melt the butter and ‘‘eook the butter milk into a ecurd.’’ The oil will now be seen mixing through the mass. The test tubes are then cooled to churning temperature and churned again, by which process the curd is broken into fine Cream Testing at Creamertes. 179 particles, which, when the butter is re-melted, will set- tle to the bottom. The butter is melted after the sec- -_ ond churning by placing the tubes in water at 150-175° F., allowing them to remain therein for at least twenty minutes. Some samples must be churned three or four times before a good separation of oil is obtained. A clear separation of oil is often facilitated by adding a little sulfuric acid to the tubes. The length of the column of liquid butter fat is de- termined by means of a special rule for measuring the butter oil; this rule shows the number of pounds and tenths of a pound of butter which an inch of cream will make; the first tenth of a pound on the rule is divided into five equal parts, so that measurements may be made to two-hundredths of a pound. The melted fat is meas- ured with the rule, by raising the tin card holding the bottles to about the height of the eye; the reading is recorded on the driver’s tablet under Test per inch, op- posite the number of the particular patron. The test multiplied by the inches and tenths of an inch of cream supplied will give the amount of butter in pounds, with which the patron will be credited on the books of the creamery. 203. The objection to this system of ascertaining the quality of cream delivered by different patrons lies in the fact that it determines the churnable fat, and not the total fat of the cream; the amount of the former obtained depends on many conditions beyond the con- trol of the patron, viz., the consistency, acidity and tem- perature of the cream, the size of the churn or churn- 180 Testing Milk and Its Products. ing vessel, etc.' The same reasons which caused the churn to be replaced by methods of determining the total fat of the milk, in the testing of cows among dairy- men and breeders, have gradually brought about the abandonment of the oil test in creameries and the adop- tion of the Babcock test in its place. It may be said, on the other hand, in favor of the use of the oil test in ereameries that it is a considerably cheaper method than any fat test, and takes less labor and time on the part of the cperators than do the latter methods. 204. The Babcock test for cream. Both the space system and the oil-test churn used for estimating the quality of cream at creameries have now largely been replaced ‘by the Babcock test in the more progressive ereameries in this country, and composite samples of eream are collected and tested in a similar manner as is done with milk at separator creameries and cheese factories. f A very satisfactory method of arrangements for working the Babcock test, in use in many eastern cream- eries, is described by Winton and Ogden in the Con- necticut report previously referred-to. The cream gatherer who collects the cream in large cream cans is supplied with a spring balance (1, see fig. 58), a pail for sampling and weighing the cream (2), sampling tube (3), and collecting bottles (5). - At each patron’s farm he takes from his wagon the sampling pail and tube, the scales, and one small collecting bottle. He should 11t follows from this that there can be no definite relation between the results obtained by the Babcock test and the oil-test readings; — a reading of 100 in the oil-test is. however, on the average, equivalent to about 23 per cent. of butter fat in the cream. — Testing Cream at Creameries. 181] find in the dairy of the patron the cans of perfectly sweet cream, kept at a temperature of 40° to 50° F., 3 and protected from dirt ea and bad odors. Either sour a or frozen cream must be rejected. The patron’s sf number should be painted in some conspicuous place near the cream cans in his dairy house. The gatherer ; a hangs the scale on a hook in An | near the cream to be col- ab Jaret 1) BFe bs lected; the scale should be Fic. 58. Outfit for cream testing made so that the hand of Beet poe. tet, at .gathcred- the dial will stand at zero when the empty pail is hung on it. The cream is then poured at least twice from one can to another in order to mix it thoroughly.’ 205. When properly mixed, the cream is poured into the weighing pail and is weighed and sampled. The authors give the following description of the cream sampling tube used, and directions for sampling and weighing the cream. ‘*Sampling Tube.—This tube is of stout brass, about ,, of an inch thick, and a few inches longer than the yee pa which 1The necessity of care in mixing the cream is pie by fae follow: ing illustration given by the authors referred to. Per cent of fat in cream which stood for 24 hours. Sample drawn . Surface. Botton. with sampling tube. INGi Mixed. 2592 Are 28.00 5.00 19.25 Poured once..-.-- pe meee ty 3. 22.00 22.50 Poureay twice. = 24. 2 2 t= ee © 22.25 182 Testing Milk and Its Products. ig used with it. On the upper end, a small brass stop-cock of the same bore is fastened. It should be nickel plated inside and out, to keep the metal smooth and free from corrosion. These tubes may be obtained from less than ,’°. to over 44 inch bore. The greater the diameter of the weighing pail, the wider should be the bore of the tube. For use with pails 8 inches in diameter, a ;; inch bore sampling tube will serve the purpose, but when the pail has a diameter of 9 or more inches, a tube with a bore of %4 inch or more should be used. It must be borne in mind that doubling the diameter of the pail, or of the sampling tube, increases its capacity fourfold. ‘*The tube when not in use should be kept in an upright posi- tion to permit draining. ‘*Sampling and Weighing.—Lower the sampling tube, cock end up, with the cock open, to the bottom of the weighing pail which holds the mixed cream. When it is filled raise it out of the liquid and allow it to drain for a few seconds. By this means the tube is rinsed with the cream to be sampled and any traces of cream adhering to the tube from previous use are re- moved. With the cock still open, slowly lower the sampling tube to the bottom of the cream pail. After allowing a moment for the cream to rise in the tube to the same height as in the pail, close the cock and raise the sampler carefully out of the cream. As long as the cock is closed, the cream in the tube will not flow out, unless the tube is strongly jarred. Allow the cream adhering to the outsiue of the tube to drain off for a few sec- onds, then put the lower end into the 1 to 1% oz. wide-mouth glass collecting bottle which bears the patron’s number on its cork, and open the cock. The cream will then flow out of the sampler into the bottle, which is afterwards securely corked and put into the cream gatherer’s case. Immediately weigh the cream in the cream pail to the quarter or half pound, as may be judged expedient, and record the weight. ‘‘If the patron has more than one pailful, repeat with each pailful the operation of sampling and weighing, putting all the samples in one and the same bottle. Weigh all cream collected in one and the same sampling pail and draw a sample from each separate portion weighed.’’ Testing Cream at Creameries. 183 206. After sampling and weighing each patron’s cream it is poured into the driver’s large can, and the sample bottles are carried in a case to the creamery where the contents of each bottle are poured into the composite sample jar of the particular patron. The samples of cream in the small bottles, besides furnish- ing the means of testing the richness of the cream, give the creamery man an opportunity to inspect the flavor of each lot of cream, and the condition in which it has been kept by the various-patrons. Some preservative, usually corrosive sublimate tablets, is placed in the com- posite sample jars, and these are cared for and tested in the same manner as composite samples of milk (194). 207. The collecting bottles should be cleaned with eold, and afterwards with hot water, as soon as they are emptied, and before a film of cream dries on them. When washed and dried, these bottles are placed in the eases, ready for the next collecting trip. There can be no confusion of bottles since the corks and not the bot- tles are marked with the numbers of the respective patrons. 208. When this system of testing composite samples is adopted, the pattons are paid for the number of pounds of butter fat contained in their cream, in the same way as milk is paid for at separator creameries. It makes no difference how thick or how thin the cream may be, or how much skim milk is left in the cream when brought to the factory. Eighty pounds of cream containing 15 per cent. of fat is worth. no more nor less than 48 pounds of cream testing 25 per cent.; in either case 12 pounds of pure butter fat is 184 Testing Cream and Its Products. delivered. This will make the same amount of butter in either case, viz., about 14 lbs., and both patrons should therefore receive the same amount of money. There is a small difference in the value of the two lots of cream to the creamery owner or the butter maker, in favor of the richer cream, both because its smaller bulk makes the transportation and handling expenses lighter, and because slightly less butter fat will be lost in the butter milk, a smaller quantity of this being ob- tained from the richer cream. But it is doubtful if the differences thus occurring are of sufficient importance to be noticed under ordinary creamery conditions; the example selected presents an extreme case of variation in the fat content of cream. A trial of this system at five Connecticut creameries, supplied mostly with Cooley cream by over 175 patrons, showed that the average composition of the cream from the different patrons varied only from 16,9 to 19.8 per cent. of fat. The cream of some patrons on certain days contained only 9.5 per cent. of fat, and other patrons at times had as high a test as 30 per cent., but these great differences largely disappeared when the average quality of the cream delivered during a period of time, like a month or more, was considered. 209. Smaller differences in the composition of cream will, however, always occur, even if the same system of creaming the milk, like the centrifugal process, is used and all factors remain as nearly the same as possible at all times. This is due to differences in the composition of the milk and its creaming quality; whether largely from fresh cows or from late milkers; whether kept Testing Cream at Creameres. 185 standing for a time before being set, or submerged in the creamer immediately after milking and straining, diameter of creaming cans, ete. Bartlett states' that the percentage of fat in the cream from the same cows may be increased ten per cent. or more by keeping the water at 70° instead of at 40° F. The higher tempera- ture will give the richer cream, but the separation will not be so complete, since a richer skim milk is obtained from the milk set at this temperature. Separator cream is not materially influenced by the conditions mentioned, as the separator can be regulated to deliver cream of nearly uniform richness from all kinds of sweet milk. 210. At creameries where both milk and cream are delivered, somewhat of an injustice is done to patrons de- livering cream, by paying for the amounts of butter fat furnished by the different patrons. By multiplying the cream fat by 1.03,? the value of his products to the creamery is taken into proper account, and justice is done to all parties concerned’ (239). 211. Gathering and sampling hand-separator cream. On account of the great variation in both the richness and the purity of farm separator cream it has been found in practice that composite samples of cream are not so satisfactory to either buyer or seller as the testing of a sample taken from each lot of cream gath- ered. A still more satisfactory method is to provide separate cans for each patron, the cream gatherer leav- 1Bull. 3 (S. S.), Maine experiment station. 2Spillman (Dairy and Creamery, Chicago, April 1, 1899) recom- mends the use of the factor 1.044. % This subject is discussed in detail in the 17th annual report of Wis. experiment station, pp. 90-92; see also the 20th report of that Station, pp. 130-31. 186 Testing Milk and Its Products. ing an empty, clean can at each farm and taking a full or partially filled can of cream from the farm to the factory. This makes it necessary for the cream gath- erer to carry aS many cans as he has patrons to gather cream from, but it gives the factory operator a chance to inspect, weigh and sample the cream from each farm and relieves the cream gatherer of all these details which are often the cause of dissatisfaction. Questions. 1. In what ways do the results obtained with the oil-test churn differ from those obtained with the Babcock test? 2. Describe the method of testing cream by the Babcock test at gathered-cream factories. 3. What advantages has the gathering of cream in separate cans over mixing the cream from all the patrons of one route? CHAPTER, XII. CALCULATION OF BUTTER- AND CHEESE YIELD = CmcoLinion OF YIELD OF BUTTER. 212. Butter-fat test and yield of butter. The Bab- cock test shows the amount of pure butter fat contained in a sample of milk, cream or other dairy products. The butter obtained by churning creain or milk con- tains, in addition to butter fat, a certain amount of water, salt and curd. While an accurate milk test gives the total quantity of butter fat found in the sam- ple of milk or cream tested, the churn cannot be de- pended upon either to leave the same amount of butter fat in the butter milk or to include the same amount of water, salt or curd in the butter at each churning. If a quantity of milk, say 3,000 lbs., be thoroughly mixed in a vat, and then divided into half a dozen equal portions, a Babcock test of the different lots will show the same percentage of butter fat in each portion. If, on the other hand, each of these lots be skimmed, and the cream ripened in different vats and churned sepa- rately, the same weight of butter from each lot of 500 lbs. of milk will not be obtained, even by the most expert butter maker, or if all the operations of skimming, cream ripening, churning, salting and butter-working were made as nearly uniform as possible. Careful operators ean handle the milk and cream so that very nearly the 188 Testing Milk and Its Products. same proportion of fat contained in the milk is re- covered in the butter in different churnings, but since the water and salt in butter are held mechanically and are not chemically combined with it, the amounts re- tained by the butter are quite variable in different churnings. 213. Variations in the composition of butter. As an illustration of the variations in the composition of butter ‘that usually occur, the analyses made in the breed tests at the World’s Fair in 1893 may be here cited; the butter was in all cases made by as nearly identical methods and under as uniform conditions as could possibly be obtained by the skilled operators hav- ing this work in charge; the average composition of 350 samples of this butter, with upper and lower limits, was as shown in the following table: Composition of samples of butter, World’s Fair, 1893. a 2 Sum of 4 7 3 : alt and | water, curd, Water Fat Curd iy Gale and as Average of 350 Per cent. | Per cent. | Per cent. | Per cent. Per cent. analyses-_-____- 11.57 84.70 .95 2.78 15.30 Lower and up- per limits. -_-- 8.63-15.00 | 76.53-88.26 D0=2.145) Mel 01-858) | Sessa sen eae Analyses of fifty samples of creamery butter taken in 1896, from the tubs ready for market at as many Wis- consin creameries, showed that no two of them were ex- actly alike in composition, but varied within the limits given on the following page :1 1 Wisconsin experiment station, bull. 56. Calculation of Butter- and Cheese Yield. 189 Summary of analyses of Wisconsin creamery butter. a um of Water Fat ard Salt ¢ be goad water poe d, ash Per cent. | Percent. | Per cent. | Per cent. | Per fea Highest .22-.2... 17.03 87 50 2.45 4.73 22.99 Eoewest-...-..-.- 9.18 77.07 36 1.30 12.50 Average -2.--.: 12.77 83.08 1.28 2.87 16.92 The preceding analyses shcw the composition of but- ter made at one place where every possible effort was taken to produce a uniform product, and of butter made at fifty different creameries, where there was more or less variation in the different operations of manufacture and in the appliances and machinery used. The ma- jority of the samples of butter analyzed, in either case, were very near the average composition given, but since there are such wide variations in the composition of the butter made by the uniform methods adopted in the World’s Fair breed tests, butter of a more uniform com- position cannot be expected from the thousands of dif- ferent creameries and private dairies which supply the general market with butter. q The analyses of the fifty samples of creamery butter, given above, show that the content of the butter fat varied from 77 to 87.5 per cent., and according to the average of the analyses, 83 pounds of butter fat was contained in, or made, 100 Ibs. of butter. There was, therefore, in this case produced 20.5 ver cent. more butter than there was butter fat, since 83:100: :100:x; therefore _ 100X100 _ =a 120.5. 190 Testing Milk and Its Products. 214. ‘‘Overrun’’ of churn over test. The yield of butter is not, however, as a rule compared with the amount of butter fat contained in the butter, but with the total butter fat of the whole milk or cream from which it was made. This ‘‘inerease of the churn over the test’’ is what is generally called overrun in cream- eries. The overrun obtained in different creameries, or even in the same creameries at different times, will be found to vary considerably. When the milk is accurately tested and the butter well worked, this overrun will vary from 10 to 16 per cent.; that is, if a quantity of milk contains exactly 100 lbs of butter fat, as found by the Babcock test or any other accurate method, from 110 to 116 lbs. of butter ready for market will be obtained from it. The overrun from cream will be somewhat larger, 18 to 22 per cent., but will never exceed 25 per cent., unless the butter contains less than 80 per cent. fat (217). 215. Factors influencing the overrun from milk. Even under the very best of care and attention to de- tails, variations will occur in the speed of the separator, in the conduct of the ripening and churning processes, and in the condition of the butter when the churn is stopped; hence absolutely uniform losses of fat in skim milk and butter milk, or the same water- and salt con- tents of the butter, cannot be expected. The overrun in separator creameries is influenced by two legitimate factors: first, the losses of butter fat sus- tained in separating the milk and churning the cream, and second, the gain due to the admixture of water, Calculation of Butter- and Cheese Yield. 191 salt, etc., in the manufacture of butter. Considering first the losses of fat in skim milk and butter milk, the separator will usually, when run at normal speed and capacity, leave the same per cent. of fat in skim milk, whether rich or poor milk is skimmed. An exception to this may be found in separating rich milk having large fat globules, or milk from fresh milkers, in either of which cases the large size of the fat globules occa- sions a more complete separation of fet by the centri- fugal force. But generally speaking, the statement holds good that the total loss of fat in separator skim milk is a factor of the quantity of milk run through the separator, rather than of its quality. 216. The losses from poor, rich and average milk, as received at creameries and cheese factories, can be traced from the following statement; this gives the quantities of fat lost in handling milk of four grades, viz.: 2.5, 3.5, 4.0 and 6.0 per cent., in case of each grade calcu- lated to a standard of 100 lbs. of fat in the milk. To supply 100 lbs. of fat would require the following amounts of the different grades of milk: 4000 lbs. of milk testing 2.5 per cent will contain 100 Ibs. of fat. 2857 CC, G6 7 66 66 ra 100 ¢6 &6 66 2500 fe et a 2 ‘6 a a 100 *« «6 ¢e 1666 sag ol Ret f: ee 100: V4! Oe Assuming that the skim milk contains .1 per cent. of fat and makes up 85 per cent. of the whole milk, and that the butter milk tests .8 per cent., and forms 10 per cent. of the whole milk, the butter-fat record of the quantities of different grades of milk containing 100 lbs. of fat will be as given in the following table. Cer- 192 Testing Milk and Its Products. tain mechanical losses are unavoidable in the cream- ery, as in all other factory operations, viz., milk and cream remaining in vats and separators, butter sticking to the walls of the churn, ete. These losses have been found to average about 3 per cent. of the total fat in the milk handled, under norma! conditions and under good management (219). Fat available for butter in different grades of milk. ] Whol | SI | Butt | 5 ie tal tal 5 e171, | Jhole Skim | Butter | % | Total | available Grade of milk milk | milk milk < | loss | for - | butter | | | | Lbs. | Lbs. | Per ct. 2.5 per cent.._-- | 4000 lbs. | 34001bs. | 400 Ibs. |: | 2.0 per ct. | .1 per ct. | .3 per ct.| | ats. 3.22 100 Ibs. | 3.41bs. | 1.2Ibs.| 8.0 | 7.6 | 82.4 3.5 per cent__-..| 2857 Ibs. | 24291bs. | 286 Ibs. | | | 3.5 per ct. | .l per ct. | .3 per ct.| Ratctce: 100 Ibs. 2.4 Voss © )))20 Ms 4) 9810) 19 la ada 4.0 per cent.....| 2500 Ibs. | 2125 Ibs. | 250 Ibs. | | | 4perect. | .lperct. | .3 per ct. | Bates 100 Ibs. | 241bs. | .TIb. 3.0 5.8 = 94.2 6.0 per cent.....| 166624 Ibs.| 1417 Ibs. | 167 Ibs. | | | 6perct. | .lperct. | .3 per ct. | Rate. 2c: 1001bs. | 141bs. | .5Ib. | 3.0 | 4.0 | 59681 The table shows that with 2.5 per cent.-milk, there is a loss of 3.4 lbs. of fat in the skim milk, a loss of 1.2 lbs. of fat in the butter milk, and of 3.0 lbs. in the creamery waste, for every 100 lbs. of fat in the whole milk, or a total loss of 7.6 lbs. from, these sources. In ease of 6 per cent. milk these losses are 1.4 lbs., .5 Ib. and 30 lbs. for skim milk, butter milk and waste, re- spectively; a total loss of 4.9 Ibs., or 2.7 lbs. less than the losses with poor milk. This difference in the losses Calculation of Butter- and Cheese Yveld. 193 shrinks to only .5 pound of fat in case of 3.5 and 4.0 per cent.-milk, when a quantity containing 100 lbs. of fat is handled in both eases. The overrun from each of the four grades of milk can be calculated for butter containing a certain per cent. of fat. Assuming the fat content of butter to be 83 per cent. on the average (213), the quantity of butter ob- tained from the 100 lbs. of fat, or rather from the por- tion thereof which is available for butter, in each case will be as follows: 100 lbs. of fat from Available | Butter cont. Overrun fat 83 per ct. fat Lbs. Lbs. Per ct. 4,000 Ibs. of 2.5 per cent. milk__~_- 92.4 113.3 11.3 2,857 lbs. of 3.5 per cent. milk___- 93.7 113.0 13.0 2,500 Ibs. of 4.0 per cent. milk___~ 94.2 113.9 135 1,666 lbs. of 6.0 per cent. milk___- 95.1 114.6 14.6 The overrun figures given above may be increased by saving some of the three pounds of butter fat lost by waste. If it were possible to entirely eliminate this loss there would be three pounds more available fat in each ease, viz., 95.4, 96.7, 97.2, 98.1 lbs. These amounts of fat will make 115, 116.5, 117.1, and 118.2 lbs. butter. corresponding to an overrun of 15, 16.5, 17.1, and 18.2% from milk of the different fat contents mentioned. All butter makers should obtain more butter from a certain quantity of milk than the Babeock test shows it to contain butter fat, but it is impossible to know ex- actly, except by chemical analysis, how much butter fat is lost in the skim milk and the butter milk, and how much water, salt and curd the butter will contain. A 13 194 Testing Milk and its Products. butter maker’s skill is shown by his ability to reduce the losses by waste in handling the milk, cream and butter, as well as the losses of butter fat in skim milk and butter milk, and his carefulness in weighing, sampling and testing the milk, cream and butter made. 217. Overrun from cream. The overrun from cream is, aS already stated, larger than from milk because there is no loss of fat in the skim milk to be consid- ered. Rich cream will give a slightly larger over- run than thin cream, for the same reasons as have been shown in the calculations of overrun from milk of dif- ferent fat contents. If similar calculations are made for cream of different richness as those given above for milk, the fat available for butter-making and the yield of butter per 100 pounds of fat in the cream will be as shown below. A mechanical loss in the process of butter-making amounting to 2 per cent. has been assumed in these calculations: 100 Ae oy in A acletile hat eee he ee Overrun Per cent Lbs. Lbs. Per cent 20 96.8 116.6 16.6 30 oY i) 117.2 ice 40 97.6 736 16 We note that the overrun for cream of different qual- ity under the conditions given ranges from 16.6 for 20- per cent. cream to 17.6 for 40-per cent. cream. A some- what larger overrun would be obtained when the butter made contains less fat and more water than assumed. If no losses from waste are considered in the account. the figures for fat available for butter will be 98.8, 99.3, Calculation of Butter- and Cheese Yield. 195 and 99.6 lbs., and the overruns when the butter contains 83% fat will be 19, 19.3, and 20 per cent. These over- runs are higher than will be obtained under ordinary ereamery conditions with butter containing 83.7% fat, because it is impossible to reduce the manufacturing losses in handling the cream and butter appreciably below 2 per cent. 217a. Maximum overrun for butter of a legal water content. If we assume that the butter contains the maximum amount of water allowed by law, viz., 16 per cent. (and therefore about 80 per cent. fat), the overrun for both milk and cream would be somewhat larger than already given, as shown by the following figures : Maximum overrun from milk Maximum overrun from cream. peegee Soe eS 15.5 See ae 17.1 it oe ee 178 | 30% -------------------- 21.6 Mie eS er berece ee a ee 22.0 This table shows the highest overruns that are likely to be obtained when the butter is to contain no more than the maximum amount of water allowed by law. Larger overruns can only be obtained by reducing the losses of manufacture (which will give but slightly higher figures) or, fraudulently, by inaccurate weigh- ing or testing of the milk, cream or butter. 218. Calculation of overrun. The overrun is caleu- lated by subtracting the amount of butter fat contained in a certain quantity of milk or cream, from the amount 196 Testing Milk and Its Products. of butter made from it, and finding what per cent. this difference is of the amount of butter fat in the milk. Example 1: 8000 Ibs. of milk is received at the creamery on a certain day; the average test of the milk is 3.8 per cent. By a simple multiplication we find that the milk contained 8000X .038=304 Ibs. of butter fat. 350 lbs. of butter was made from this milk, as shown by the weights of the packed tubs. The dif- ference between the weight of butter and butter fat is, therefore, 46 lbs.; 46 is oe =15.1 per cent. of the quantity of the butter fat in the milk; that is, the overrun for the day considered was 1StLoper scent, The formula for the overrun is as follows: _(b--) £100 f b and f designating the quantities of butter and butter fat, respectively, made from or contained in a certain quantity of milk. In the preceding example, the caleu- lation would be as follows: Cnn) 100: 151 penecna Example 2: 1000 Ibs. of cream testing 25 per cent. fat con- tains 1000X.25—250 Ibs. butter fat. If 304 lbs. of butter is made, the overrun may be calculated by subtracting the butter fat from the butter, 304—250—54 Ibs., then divide this by the 2 IN 21.8 per cent., 19) xX fat in the cream and multiply by 100; or which is the cream overrun. 219. Conversion factor for butter fat. In the ninety- day dairy test at the World’s Columbian Exposition, 96.67 per cent. of the fat in the whole milk was recovered in the butter. This butter, on the average, contained 82.37 per cent. butter fat; in other words, 117.3 pounds of butter were made from each 100 pounds of butter fat in the whole milk.t | The exact conversion factor 1When 82.37 lbs. of butter fat will make 100 Ibs. of butter, how much butter will 96.67 Jbs. of butter fat make? 83.37 :96:17 ::100 :x, x=117.3, ‘Calculation of Butter- and Cheese Yield 197 would be 1.173. As this is an awkward number to use, and as 11% is so nearly the same, it was recommended at the time that the approximate equivalent of butter be computed by multiplying ‘the amount of butter fat by 11%, and this figure has been generally accepted for computing the yield of butter from a certain amount of butter fat in milk. The figures given are the result of more than ordinary care in skimming, churning and testing, and probably represent the minimum losses of fat in the manufactur- ing processes. The increase of churn over test repre- sented by one-sixth, or 16 per cent., may therefore be taken as a maximum ‘‘overrun’’ for milk under ordi- nary factory conditions. 220. Butter yield from milk of different richness. a. Use of butter chart. The approximate yield of but- ter from milk of different richness is shown in Table XI in the Appendix. This table is founded on ordinary creamery experience and will be found to come near to actual every-day conditions in creameries where modern methods are followed in the handling of the milk and its products. The table has been prepared in the fol- lowing manner: It is assumed that the average loss of fat in the skim milk is .20 per cent., and that 85 lbs. of skim milk is obtained from each 100 lbs. of whole milk; to this loss of fat is added that from the butter milk; about 10 Ibs. of butter milk is obtained per 100 Ibs. of whole milk, testing on the average .30 per cent. If f designate the fat in 100 lbs. of milk, then the fat recov- ered in the butter from 100 lbs. of milk will be f= (aX 20-4 ae 30)= f—.2 198 Testing Milk and Its Products. There is, on the other hand, an increase in weight in the but- ter made, owing to the admixture of non-fatty components therein, principally water and salt. Butter packed and ready for the market will contain in the neighborhood of 84 per cent. of fat (214), so that the fat recovered in the butter must be in- creased by 1991.19. If B therefore designate the yield of but- ter from 100 lbs. of milk, the following formula will express the relation between yield and fat content, provided there are no other factors entering into the problem, viz.: B=(f—.20) 1.19 From this value for B, should be deducted the loss due to wastes in the manufacturing processes, amounting to 3 per cent. of the total fat in the milk handled, and we therefore have: B= (90) 1-16 Since this table is based on a fat content of .2 per cent. in the skim milk, the figures for the overrun are slightly lower than may be obtained in creameries pro- vided with up-to-date cream separators. 221. Table XI in the Appendix, founded on this formula, may be used to determine the number of pounds of butter which milk containing 3 to 5.3 per cent. fat will be likely to make. It presupposes good and careful work in separating and churning and under such conditions will generally show yields of butter varying but little from those actually obtained. It may be conveniently used by the butter maker or the manager to check up the work in the creamery; the average test of the milk received during a certain period is found by dividing the total butter fat received, by the total milk, and multiplying the quotient by 100; the amount of butter which the total milk of this average fat con- tent will make, according to the table, is then compared with the actual churn yield. Calculation of Butter- and Cheese Yield. 199 Example: A creamery receives 200,000 Ibs. of milk during a month; the milk of each patron is tested and the fat contained therein calculated. The sum of these amounts of fat may be 7583 lbs; the average test of the milk is then 3.79 per cent. Ac- cording to Table XI, 10,000 Ibs. of milk, testing 3.8, will make 418 lbs. of butter, and 200,000 lIbs., therefore, 8360 Ibs. of but- ter. The total quantity of butter made during the month will net vary appreciably from this figure if the work in the cream- ery has been properly done. 222. b. Use of overrun table. The table referred to above gives a definite calculated butter yield for each grade of milk, according to average creamery condi- tions. As it may be found that this table will give uni- formly either too low or too high results, Table XII in the Appendiz is included, by means of which the butter yield corresponding to overruns from 10 to 20 per cent. may be ascertained in a similar way as above described. The total yield of butter is divided by the total num- ber of pounds of fat delivered ; the quotient will give the amount of butter made from one pound of fat, and this figure multiplied by the fat delivered by each pat- ron shows the pounds of butter to be credited to each patron. To use the table, find in the upper horizontal line the number corresponding nearest to the number of pounds of butter from one pound of fat. The vertical column in which this falls gives the pounds of butter from 100 lbs. of milk containing the per cents. of fat given in the outside columns (Babcock). B.—CALCULATION OF YIELD OF CHEESE. 223. a. From fat. The approximate yield of green Cheddar cheese from 100 Ibs. of milk may be found by multiplying the per cent. of fat in the milk by 2.7; if f 200 Testing Milk and Its Products. designate the per cent. of fat in the milk, the formula will, therefore, be: Yield. of cheese= 25-4, > Svs Sse a The factor 2.7 will only hold good as the average of a large number of cases. In extensive investigations dur- ing three consecutive years, Van Slyket found that the number of pounds of green cheese obtained for each pound of fat in the milk varied from 2.51 to 3.06, the average figures for the three years 1892-’94, inclusive, being 2.73, 2.71, and 2.72 lbs., respectively. The richer kinds of milk will produce cheese richer in fat, and will yield a relatively larger quantity of cheese, pound for pound, than poor milk, for the reason that an in- crease in the fat content of milk is accompanied by an increase in the other cheese-producing solids of the milk. The preceding formula would not, therefore, be correct for small lots of either rich or poor milk, but only for milk of average composition, and for large quantities of normal factory milk. For cured cheese the factor will be somewhat lower, viz., about 2.6, on the average. 224. b. From solids not fat and fat. If the percent- ages of solids not fat and of fat in the milk are known, the following formula by Babcock will give close results: Yield of green cheese=1.58 (-$-+.91f) a te an 1N. Y. experiment station (Geneva), bulletins 65 and 82. * Investigations as to the relation between the quality of the milk and the yield of cheese have been conducted by a number of experi- ment stations; the following references give the main contributions published on this point; N. Y. (Geneva) exp. sta., reports 10-13, incl. ; Wis. exp. sta., reports 11 and 12, bull. 197; Ont. Agr. College, reports 1894-96, incl.; Minn. exp. sta., b. 19, reports 1892-’94, incl. ; Iowa exp. sta., bull. 21; Hoard’s Dairyman, 1892, p. 2400. Calculation of Butter- and Cheese Yveld. 201 - gs being the per cent. of solids not fat in the milk, and f the per cent. of fat.? The solids not fat ean be readily ascertained from the lactometer reading and the per cent. of fat as shown in par. 120, by means of Table VI in the Appendix. Table XIII in the Appendix gives the yield of cheese from 100 lbs. of milk containing from 2.5 to 6.0 per cent. fat, the lactometer readings of which range be- tween 26 and 36. By means of this table cheese makers ean calculate very closely the yields of cheese which certain quantities of milk will make; as it takes into consideration the non-fatty solids as well as the fat of the milk, the results obtained by the use of this formula will be more correct than those found by means of formula (1). The uncertain element in the formula lies in the factor 1.58, which is based on an average water eontent of 37 per cent. in the green cheese. This may, ‘however, be changed to suit any particular case, e. g, 30 per cent. (1,°2°—1.54), 40 per cent. 1° =1.67, ete. The average percentages of water in green cheese found by Van Slyke in his investigations referred to above, were for the years 1892-’94, respectively, 36.41, 37.05 and 36.70 per cent. 225. c. From casein and fat. If the percentages of casein and fat in the milk are known, the yield of cheese may be calculated by the following formula, also pre- pared by Dr. Babcock: Yield of cheese=1.1 f+2.5 casein . .. . (III). This formula will give fairly correct results, but no more so than formula (JI); it is wholly empirical. 1For derivation of this formula, see Wisconsin experiment station, twelfth report, p. 105. 202 Testing Milk and Its Products. Questions. 1. What is the average composition of American creamery butter, and between what extremes does the composition of butter vary? 2. What is the difference between the churn yield and the re- sults obtained by the Babcock test? 3. What does the overrun represent? 4. Mention several factors that cause a large overrun. 5. Give an illustration of how the per cent. of increase of churn over test is found, and how the overrun is calculated. 6. Show by an example that butter containing 80% fat can- not give an overrun of more than 25%. 7. How many pounds of butter containing 80% fat can be made from 100 lbs. fat? 8. Why is the overrun from cream greater than from milk? 9. What is the overrun when 70.5 lbs. of butter are made from 140 Ibs. of milk, testing 3.15 per cent? 10. What is the overrun in each of the following cases? 220 Ibs. butter from 8000 Ibs. milk, testing 2.3% fat. 250 Ibs. butter from 4000 Ibs. milk, testing 5.8% fat. 600 lbs. butter from 2000 lbs. cream, testing 25.0% fat. 480 lbs. butter from 1000 lbs. cream, testing 40.0% fat. 11. How much butter containing (a) 80% fat, and (b) 82.5% fat can be made from 3250 lbs. milk, testing 4.3% fat, assum- ing that the skim milk is 80% of the whole milk and contains 0.1% fat, and the butter milk, which is the cream minus the fat, contains 0.25% fat? What is the overrun in each case? 12. How much butter is obtained from 5800 lbs. milk, testing 3.7% fat, when the overrun is (a) 12.5% and (b) 16%? 13. Two cows in full milk produce, one 17.5 lbs. of milk a day, containing 4.35% fat; the other, 27.3 Ibs. of milk, testing 3.4%. If the milk of both is made into butter or cheese, how much butter or cheese may be expected from each one in a week? 14. What is a fair percentage of loss of fat by waste other than in skim milk and butter milk under average creamery con- ditions in case of milk and cream? 15. How much butter may be made from (a) 15,640 Ibs. milk, testing 3.8% fat, and (b) 35,842 lbs. milk, testing 4.1% fat? (Use Table XI, Appendix.) CHAPTHR. KITE: CALCULATING DIVIDENDS. A.—CALCULATING DIVIDENDS AT CREAMERIES. 226. The simplest method of calculating dividends at ereameries is to base the calculations on the amount of butter fat delivered by the various patrons. Each lot of milk is weighed when delivered at the creamery, and a small quantity thereof is saved for the composite sam- ple, as previously explained under Composite Tests (180). Some creameries test these samples at the end of each week, and others after collecting them for ten days or two weeks. If the four weekly composite sam- ples of a patron’s milk tested 3.8, 4.0, 3.9, 4.1 per cent., these four tests are added together, and the sum divided by 4; the result, 3.95 per cent., is used as the average test of this milk. By multiplying the total number of pounds of milk delivered by this patron, by his average test, the total weight of butter fat in pounds delivered to the factory during the month is obtained. This weight of fat is then multiplied by the price to be paid by the creamery per pound of butter fat; the product shows the amount of money due this patron for the milk delivered during the time samples were taken. 227. Price per pound of butter fat. The method of obtaining the price to be paid for one pound of butter fat varies somewhat in different creameries, on account of the different ways of paying for the cost of manu- 204 Testing Milk and Its Products. facturing the butter. The method to be followed is generally determined by agreement between the manu- facturer and the milk producers, in case of proprietary creameries, or among the shareholders, in co-operative creameries. The following methods of paying for the cost of manufacture are at the present time in use in American creameries. 228. I. Proprietary creameries. Just.—When the creamery is owned by some one person or company, the owner or owners agree to make the butter for about 3 cents a pound; the difference between the total receipts of the factory and the amount due the owner is then divided between the different patrons, according to the amount of butter fat contained in the milk which they delivered. The price charged for making butter varies from 214 to 4 cents per pound; the larger the amount of milk received at a factory, the lower will naturally be the cost of manufacturing the butter. Second.—The proprietor of the creamery sometimes agrees to pay a certain price for 100 lbs. of milk deliv- ered, according to its fat content, the price of milk con- taining 4 per cent. of butter fat being the standard. This price may be changed during the different seasons of the year by mutual agreement. Third.—A creamery owner may offer to pay 1 to 2 cents, usually 114 cents, below the average market price of butter, for each pound of butter fat received in the milk. 1 Bull. 56, p. 26, Wisconsin exp. station; see Report 18, Iowa State Dairy Commissioner, p. 383. Calculating Dividends. 205 229. II. Co-operative creameries. Where the ereamery is owned by the patrons, one of the stock- holders who is elected secretary attends to the details of running the factory and selling the product. His ac- counts show the amount of money received each month for the butter and other. products sold, and the expenses of running the factory during this time. The expenses are subtracted from the receipts, and the balance is divided among the patrons, each one receiving his pro- portionate share according to the amounts of butter fat delivered in each case, as shown by the total weight and the average test of milk delivered during this time. In nearly all cases, the farmers receive about eighty pounds of skim milk for each one hundred pounds of whole milk they deliver to the factory, in addition to the amount received for the milk, calculated according to one or the other of the preceding methods. 230. Illustration of calculation of dividends. In order to illustrate the details of calculating dividends, or the amount to be paid each patron for the milk delivered, when payments are made by each of the four systems given, it will be assumed that a creamery receives 5000 pounds of milk daily during a month, and makes 6650 Ibs. of butter from the 150,000 Ibs. of milk received during this time. The average test of this milk. may be found by multiplying the total weight of milk delivered by each patron by his average test, and dividing the sum of these products by the total weight of milk received at the cream- ery (in the example given, by 150,000), the quotient being mul- tiplied by 100. Such calculations may show that, e. g., 5700 Ibs. of butter fat have been received in all the milk delivered by the different patrons; this multiplied by 100 and divided by 150,000 gives 3.8 as the average test, or the average amount of butter fat in each 100 Ibs. of milk received during the month. So far the method of calculation is common for the different systems of payment given above; the manner of procedure now 206 Testing Milk and Its Products. differs according to the agreement made between owner and patrons, or among the shareholders, in case of co-operative creameries. 231. I. First——If the net returns for the 6650 lbs. of butter sold during the month were $1197, and the creamery is to re- ceive 4 cents per pound of butter as the cost of manufacture, etc., the amount due the creamery is 6650X.04—$266, and the patrons would receive $1197—$266—$931. This sum, $931, is to be paid to the patrons for the 5700 lbs. of butter fat, which, as shown above, was the weight of fat contained in the 150,000 Ibs. of milk delivered during the month. The price of one pound of butter fat is then easily found: $931+5700=16% cents. This price is paid to all patrons for each pound of butter fat deliv- ered in their milk during the month. The monthly milk record of three patrons may, e. g., be as given in the following table: | Hist necond Third EouEtD | | week week week week | » ; | Total | Average ae i Milk | test Milk | Test || Milk] Test || Milk | Test || Milk | Test | eile wh ape ee ||| gral: | ee) |Lbs.| % ||Lbs.| % || Lbs.) % ||Lbs.| % || Lbs. || % INO e222 S000 326 3000 | 3.5 3600 | 3.65]) 3450 | 3:45 || 13,550 || 3.55 INO M2 ee Us ons 665 | 3.8 (205) 320 750 | 3.7 || 2,825 | 3.73 No.3 --__| 2480 | 4.2 2000 | 3.8 1850 | 4.0 1500 | 3.6 7,830 | 3.90 Multiplying each patron’s total milk by his average test gives the number of pounds of butter fat in his milk, and this figure multiplied by .1644 shows the money due for his milk, as given below: Patron 7 Sabet | gerne of Bateers ce ae ee Lbs. Percent - Lbs. Cents Nordea eee, 13,550 3.95 481.0 161% $78.56 INO ae eee 2,835 3.7 104.5 161% 17.06 Novouas2 4 7,830 | 3.9 305.4 1614 48.87 232. Second.—When the proprietor of a creamery agrees to pay a certain price for 100 lbs. of 4 per cent. milk, the receipts for butter sold and the price per pound of butter do not enter into the calculation of the amount due each patron for his milk; Calculating Dividends. 207 but the weight and the test of each patron’s milk are as im- portant as before. If it is agreed to pay 66 cents per 100 lbs. of 4 per cent. milk (i. e., milk containing 4 per cent. of butter fat), the price of one pound of butter fat will be 6644=—16% cents, and the amount due each patron is found by multiplying the total weight of butter fat in his milk by this price. To facilitate this calculation, so-called Relative-Value Tables have been constructed, the use of which is explained below (238). 233. Third—If a creamery agrees to pay for butter fat, say 1% cents per pound below the average market price of butter each month, the price of one pound of butter fat is found by averaging the market quotations and subtracting 1% cents there- from. If the four weekly market prices were 1714, 17, 16% and 19 cents, the average of these would be 17% cents, and this less 1% gives 16 cents as the price per pound of fat to be paid to the patrons; this price is then used in calculating the dividend as in case of first method (231). Total Average | Butter | Price of fat| Amount Patron mitk test fat per lb. due Lbs. Per cent Lbs. | Cents iy 0 ys ae aaa 13,550 Sue 481.0 16 $76.96 cif pat a 2,825 3.7 104.5 | 16 16.72 [sae ee ae 7,830 3.9 | 305.4 | 16 48.86 234. II. If the creamery is owned by the farmers, the run- ning expenses for a month are subtracted from the gross returns received for the butter, and the price to be paid per pound of butter fat is found by dividing the amount left by the total number of pounds of butter fat delivered during the month. This price is used for paying each patron for his milk according to the amount of fat contained therein, as already explained un- der Proprietary Creameries (231). The monthly running expenses of a co-operative creamery gen- erally include such items as the wages of the butter maker (and manager or secretary, if these officers are salaried), labor (haul- ing, helper, ete.), cost of butter packages, coal or wood, salt and other supplies, freight and commission on the butter sold, repairs and insurance on buildings, ete. A certain amount is also paid into a sinking fund (say, 5 cents per 100 lbs. of milk), 208 Testing Milk and Its Products. which represents the depreciation of the property, wear and tear of building and machinery, bad debts, etc. These items are added together, and their sum subtracted from the gross receipts for the butter sold during the month. 235. Assuming the receipts for the butter during the month to be $1197, and the running expenses of the factory $285, the amount to be divided among the patrons is $912; the quantity of butter fat received was 5700 Ibs., and the price per pound of butter fat will therefore be 16 cents. The account will then stand as given in (233). 236. Other systems of payment. Besides these four systems of payment, there are various other agreements made between manufacturer and producer, but with them all the one important computation is the price to be paid per pound of butter fat; this forms the basis of calculating the factory Aidends, when milk is pee for by the Babcock test. 237. Paying for butter delivered. In some instances patrons desire to receive pay for the quantity of butter which the milk or cream delivered by them would make. This can be ascertained quite satisfactorily from the total receipts and the total weights of both butter fat and but- ter. The total money to be paid for butter (the net re- ceipts) are divided by the number of pounds of butter sold, to get the price to be paid per pound of butter; the total yield of butter divided by the total amount of butter fat delivered in the milk, gives the amount of butter corresponding to one pound of butter fat, and the number of pounds of fat delivered by each patron is then multiplied by this figure. This method requires more figuring than those given in the preceding, and the dividends are no more accurate, in fact less so, than when calculations are based on the price per pound of fat. Calculating Dividends. 209 237a. Making butter ‘‘for the overrun.’’ When cream is bought on the basis of paying the market price of butter for each pound of butter fat in the cream, the margin received by the cream buyer, if he makes this cream into butter, is influenced both by the price of butter and the per cent. of overrun he obtains. If the price of butter is 20c. and the overrun is 20%, each pound of butter fat makes 1.2 lbs. of butter, and the buyer receives 24 cents for the butter, or 4 cents margin on the 1.2 lbs. of butter made, which is equal to 314 cents per pound of butter. If the price of butter is 36 cents, and the overrun 20%, the cream buyer receives 1.23648 cents for the butter, or 7 cents for 1.2 lbs. of butter, equivalent to 5.8 ce. per pound of butter. 238. Relative-value tables. These tables give many of the multiplications used in computing the amount due for: various weights of milk of different fat con- tents. They can easily be constructed by any one as soon as the price of one pound of fat is determined in each case. If the price to be paid per pound of fat is, Say 25 cents, the value of each 100 Ibs. of milk of different quality is found by multiplying its test by 25. If the average tests of the different patrons’ milk vary from 3 to 5 per cent., the relative-value table would be as follows. 3.0X25=75e. per 100 Ibs. | 3.6X 25—90e. per 100 Ibs. 3.1X 25=77.5e. es 3.7 X25—92 5e. fe 3.2 X 25—=80e. nF 3.8 X 25=95.0e. us 3.3 X 25—82.5e. 2 | 3.9 X 25—97.5e. rf 3.4 X 25—85.0e. pL PRA 4 0X25—=100e. ~ 3.5 X 25—87.5e. she | etc. By continuing this multiplication, or adding the mul- tiplier each time for each tenth of a per cent. up to 5 14 210 Testing Milk and Its Products. per cent. of fat, a table is made that can be used for calculating the amount due per 100 lbs. of milk at the price per pound given, and the weight of milk delivered by each patron is multiplied by the price per 100 lbs. of milk shown in the table opposite the figure representing his test. Example: A patron supplies 2470 Ibs. of milk, testing 3.2 per cent. of fat; price per pound of fat, 25 cents; he should then receive 24.70 X.80—=$19.76 (see above table). Another pat- ron delivering 3850 lbs. of milk testing 3.8 per cent. will re- ceive, at the same price per pound of fat, 38.50 .95=$35.57. The relative-value tables in the Appendix give the price per 100 lbs. of milk testing between 3 and 6 per cent. fat, when the price of three per cent. milk varies from 30 to 90c. per 100 Ibs. In using the tables, first find the figure showing the price which it has been de- termined to pay for 100 lbs. of milk of a certain qual- ity, say 3 or 4 per cent.-milk; the figures in the same vertical column then give the price to be paid per 100 lbs. of milk testing between 3 and 6 per cent. Example 1: It has been decided to pay 90 cents per 100 Ibs. of 4 per cent.-milk. The figure 90 is then sought in the table in the same line as 4.0 per cent., and the vertical column in which it is found gives the price per 100 Ibs. of 3 to 6 per cent.-milk ; 3.8 per cent.-milk is thus worth 85 cents per 100 lbs. and 4.5 per cent.-milk, $1.01, under the conditions given. The prices of milk of other qualities are found in the same way. Example 2: In the example referred to under Illustrations of calculating creamery dividends (I b, 231), the figures for the patrons Nos. 1, 2 and 3, would be as follows: Patron Milk delivered Evouiee | ear ae ae Lbs. Per cent | Cents Naseer 13,550 3.55 58.5 $79.26 Noy .2 se eee 2,825 Oak 61.0 17.23 Won esa 7,830 3.9 64.0 50211. Calculating Diwidends. 214 239. Milk- and cream dividends. When cream from farm hand separators or other sources is brought to a factory receiving and skimming whole milk, the cream patron’s dividend should be calculated a little differ- ently than that of the milk patron (210). In one case the dividend is based on the weight and the test of cream and in the other on the weight and the test of milk; the difference between the two being represented by the fat left in the factory skim milk. This skim milk fat is included in the milk patron’s dividend and consequently ought also to be allowed for in calculating the amount due the cream patron. Such an allowance can be fairly made by multiplying the eream fat by 1.03. The amounts of fat thus obtained represent very nearly the fat in the milk from which the cream was skimmed and assumes that the fat re- turned to the milk patron in his skim milk is about three per cent. of the total fat in his whole milk. Since both milk and cream patron suffer the same manufacturing losses in the butter milk, an equaliza- tion of the skimming losses is all that is necessary in order to put both on a uniform basis for calculating dividends. 240. The following illustration will help to make these cal- culations clearer. Milk patron No. 1 delivers to the creamery during the month 5320 Ibs. of milk testing 3.8 per cent. fat, which therefore contains (3) =202 Ibs. butter fat. If the price paid the patrons is 20c., then 202 multiplied by 20 amounts to $40.40, the money due this patron for his milk. If another pat- ron sent 485 lbs. of cream testing 22.0 per cent. fat to the same factory during the month, the weight of fat in the cream is first found in the same way as in the milk. (S** ) 106.7 Ibs. but- 212 Testing Milk and Its Products. ter fat. Now, instead of multiplying this butter fat by 20c., as was done for the whole milk patron, it must first be multiplied by 1.03. 106.7X1.03=109.9 lbs. butter fat which is now multi- plied by 20c. per pound, giving $21.98. This is the amount due the cream patron when both milk and. cream are received at the same factory and the cream from both patrons is churned to- gether." 241. The amount of cheese made from a certain quan- tity of milk depends, as before shown, in a large meas- ure on the richness of the milk in butter fat (223). Rich milk will give more cheese per hundred weight than poor milk, and within the ordinary limits of nor- mal factory milk the inereased yields will be nearly, but not entirely, proportional to the fat contents of the dif- ferent kinds of milk. Since the quality of the cheese produced from rich milk is better than that of cheese made from thin milk and will demand a higher price, it follows that no injustice is done by rating the value of milk for cheese production by its fat content. This subject was discussed frequently during the nineties in experiment station publications and in the dairy press (223). Among others, Babeock has shown that the price of cheese stands in a direct relation to its fat content.” Prof. Robertson, ex-Commissioner of Agriculture of Can- ada, is authority for-the statement that the quality of the cheese made from milk containing 3.0 to 4.0 per cent. of fat was increased in value by one-eighth of a cent per pound for every two-tenths of a per cent. of fat in the milk,’ a figure which is fully corroborated by 117th report Wis. exp. station, p. 90; 20th report, pp. 180-131. ? Wisconsin exp. station, 11th report, p. 1384. 3’ Hoard’s Dairyman, March 29, 1895. Calculating Dividends. 213 Dr. Babcock’s results. The injustice of the ‘‘pooling system,’’ by which all kinds of milk receive the same price, is evident from the preceding; if the milk of a certain patron is richer than that of others, it will make a higher grade of cheese, and more of it per hundred- weight; hence a higher price should be paid for it. Payment on the basis of the fat content of milk is, therefore, the most equitable method of valuing milk for cheese making, and in ease of patrons of cheese fac- tories aS with creamery patrons, dividends should be calculated on the basis of the results obtained by test- ing the milk delivered. The testing may be conven- iently arranged by the method of composite sampling, in the way already described for creameries (180). 242. Cheese factory dividends. (a) Dividends based on fat test alone. As in the case. of creameries, the price to be paid per pound of butter fat must first be ascertained. The factory records should show the number of pounds of cheese made from the total milk delivered to the factory during a certain time, generally one month, and the money received for this cheese. The cost of making the cheese and all other expenses that should be paid for out of the money received for the cheese, are deducted from the total receipts, and the difference is divided among the patrons in proportion to the amounts of butter fat delivered in the milk. The weights of the milk delivered and the tests of the composite samples furnish data for calculating the quantities of butter fat to be credited to each patron. 214 Testing Milk and Its Products. The money to be paid to the patrons is then divided by the total weight of butter fat delivered to the factory and the price of one pound of fat thus obtained. The money due each patron is now found by multiplying the total number of pounds of butter fat in his milk by this price per pound. (b) Dividends based on fat and solids-not-fat (lacto- meter readings). A close estimate of the cheese value of each patron’s milk may be made, as explained in par. 224, b., by the use of table XIII in the Appendiz. When the cheese yield of each patron’s milk is found by this method, the money to be distributed among the patrons is divided by the sum of the figures found by these two tests, instead of by the total butter fat. The figure thus obtained is the price to be paid each patron per pound cheese that may be made from his milk as shown by both the fat test and the lactometer reading. (ce) Dividends based on ‘‘the fat plus two method.’ The money due patrons for milk delivered at cheese factories may be calculated by adding two to the per cent. of fat in the milk, and otherwise proceeding as explained above under par. 242a. This is the method advocated by Prof. H. H. Dean of Guelph (Ont.) Ag- ricultural college: It has been adopted at many Cana- dian cheese factories and at some factories in this coun- try. (d) Dividends based on the fat and casein tests. The results obtained by the fat test and the Hart casein 1 Bull. 114,.Ont. Agr. College; see also Dean, Canadian Dairying, p. 146. Calculating Dividends. 215 test (258) are added together; the pounds of milk de- livered by each patron are multiplied by this figure and the preduct multiplied by the price to be paid for the sum of the fat and the casein.t This price per pound is obtained in the same way as the price per pound of fat. Each patron’s milk is multiphed by the sum of the fat and the casein tests and the money to be distributed to the patrons is divided by the sum of these figures obtained for all patrons for the period covered. The illustrations already given for calculating patrons’ dividends at creameries according to the various meth- ods will serve equally well to show the manner in which dividends are calculated at a cheese factory. For the sake of clearness an example is given that applies di- rectly to cheese factories. 243. Illustration of calculation dividends. It may be assumed that 15,000 llbs. of green cheese is made from 150,000 Ibs. of milk delivered to a factory in a month. According to the weighings and the tests made, the milk contained 5,700 Ibs. of butter fat. If the cheese sold at an average price of 714 cents a pound, the gross receipts would be $1,125.00. The amount to be deducted from the gross receipts will depend on the agree- ment made between the factory operator and the patrons, in case of proprietary cheese factories, or between the shareholders and the maker, when the factory is run on the co-operative plan. As before we shall consider these systems separately. 244. I. Proprietary cheese factories. The owner of the factory generally agrees to make the cheese for a certain price per pound and to pay the patrons what is left after deducting this amount. If the price agreed on is 1% cents per pound of green cheese, this would amount to $225 in the example given. Subtracting this sum from the gross receipts, $1,125, leaves $900, 1 Wisconsin expt. station, bull. 197. ZiGs Testmg Milk and Its Products which is to be paid the patrons. The total amount of butter fat delivered by the patrons was 5,700 lbs.; hence the price of one pound of butter fat will be 900+5,700=.1577, or 15.8 cents. Taking the figures for the three patrons already mentioned un- der Creamery Dividends, we then have: Patron Total milk Ee Butter fat Roe a Asnoune ee . Per cent ‘ are: Cents Noa ss2 7s RAs sO 3.909 481.0 15.8 $76.00 Nos 223 2,825 Oot 104.5 15.8 16.51 ING tko =e 7,830. 3.9 305.4 15.8 48.25 245. II. Co-operative cheese factories. The method of pay- ment at co-operative cheese factories is nearly the same as that already given, except that a certain sum representing the ex- penses is subtracted from the gross receipts for the cheese, and the balance is divided among the patrons according to the amount of butter fat furnished by each, in the same manner as in the above case, after the price of a pound of fat has been obtained. The price per 100 lbs. of milk can be calculated in the same way as at creameries, by multiplying the test of each lot by the price per pound of fat. Questions. 1. How much money is due each of three patrons of a cream- ery when the following weights of milk are delivered by each: A— 5750 Ib. milk, composite tests, 4.0—4.8—4.2 per cent. B— 955 lb. milk, composite tests, 4.6—5.0—4.8 per cent. C—10,538 lb. milk, composite tests, 3.2—3.5—3.0 per cent. (a) When 700 Ibs. of butter are sold for $200, and the cost of making is 3%e. per Ib; (b) When the factory agrees to pay $1.00 per 100 lbs. milk, testing 4% fat; 1 Suggestions regarding the organization of co-operative creameries and cheese factories will be found in the Appendix, following Table XV. Draft of constitution and by-laws for co-operative factory as- sociations are also given in the Appendix. It is hoped that these will prove helpful to farmers who contemplate forming such associations. CHAPTER XIV. CHEMICAL ANALYSIS OF MILK AND ITS PRODUCTS. 246. An outline of the methods followed in determin- ing quantitatively the main components of milk and its products is given in the following for the guidance of advanced dairy students. This work cannot be done outside of a fairly well-equipped chemical laboratory, or by persons who have not been accustomed to handling delicate chemical apparatus and glassware, analytical balances, etc., and who have not a knowledge of, at least, the elements of chemistry and chemical reactions. A.—MILK. 247. In a complete milk analysis, the specific gravity of the milk is determined, and the following milk com- ponents: water, fat, casein and albumen, milk sugar, and ash. The methods of analysis described in the fol- lowing are those adopted by the Association of Official Agricultural Chemists of North America, which, with but slight modifications, are in general use in the chemi- eal laboratories of all American experiment stations and agricultural colleges.* 248. a. Specific gravity is determined by means of a picnometer or specific-gravity bottle, since more ac- 1The complete methods of analysis adopted by the Association of Official Agricultural Chemists are published by the Bur. of Chemistry of the U. S. Department of Agriculture; see Bull. No. 107, pp. 117-128. 218 Testing Milk and Its Products. curate results will thus be reached than by using an or- dinary Quevenne lactometer. A thermometer is ground into the neck of the specific-gravity bottle so as to form a Stopper, and the bottle is provided with a glass-stop- pered side-tube, to furnish an exit for the liquid on ex- panding. A specific-gravity bottle holding 100 grams of water is preferably used. The empty and scrupu- lously cleaned bottle is first weighed on a chemical bal- ance. The bottle is then filled with recently-boiled dis- tilled water of a temperature below 60° F. (15.5° C.); the thermometer is inserted, and the bottle is warmed slightly by immersing it for a moment in tepid water and left standing until the thermometer shows 60° F.; the opening of the side tube is then wiped off and closed with the stopper, and the water on the outside of the bottle and in the groove between its neck and the ther- mometer is wiped off with filter paper or a clean hand- kerchief, when the bottle is again weighed. The weight being recorded; the bottle is emptied and dried in a water oven, or if sufficient milk is at hand, the bottle is repeatedly rinsed with the milk, the specific gravity of which is to be determined. It is then filled with milk in a Similar manner as in case of water; the tempera- ture of the milk should be slightly below 60° F. and is slowly brought up to this degree after the bottle has been filled, proceeding in the same way as before with water; the weight of the bottle and milk is then taken. The weights of water and of milk contained in the specific-gravity bottle are found by subtracting the weight of the empty bottle from the second and the third weights, respectively, and the specific gravity of Chemical Analysis of Milk and Its Products. 219 the milk then found by dividing the weight of the milk by that of the water. Example: Weight of sp. gr. bottle+water...146.9113 grams. Weight of sp. gr. bottle empty... 46.9423 grams. Weight Of water. <:./025 x's. 99.9690 grams. Weight of sp. gr. bottle-+milk.....149.8708 grams. Weight of sp. gr. bottle empty... 46.9423 grams. Weight: of milk; 5 5/5% so. 2 102.9285 grams. Sp. gr. of milk—2-"—1 0296. 249. If a plain picnometer without a thermometer attached is available, the method of procedure is similar to that described, with the difference that the temperature of the water and of the milk must be brought to 60° F. before the picnometer is filled, or the picnometer filled with either liquid is placed in water in a small beaker, which is very slowly warmed to 60° F. and kept at this temperature for some time so as to allow the liquid in the picnometer to reach the temperature desired; th temperature of the water in the beaker is ascertained by means of an accurate chemical thermometer. The perforated stopper is then wiped off, the picnometer is taken out of the water, wiped and weighed. It is necessary to weigh very quickly if the room temperature is much above 60° F.. as in such cases the expanding liquid will flow on to the balance pan, with a resultant loss in weight from evaporation. The weights of specific-gravity bottle or picnometer, empty and filled with water, need only be determined a couple of times, and the averages of these weighings are used in subsequent de- terminations. 250. Westphal balance. Where only a small amount of milk is available, or in rapid work, the specific grav- ity may be taken with considerable accuracy by means of a Westphal balance. The arrangement and use of this convenient little apparatus is readily explained verbally. 220 Testing Milk and Its Products. For the determination of the specific gravity of lop- pered muk, see 263. | 251. b. Water. The milk is weighed into a perfor- ated copper tube filled with prepared dry asbestos. The tubes are made from perforated sheet copper, with holes about .7 mm. in diameter and about .7 mm. apart; they are 60 mm. long, 25 mm. in diameter and closed at the bottom. The asbestos is prepared from clean fibrous asbestos, which is ignited at low heat in a muffle oven, treated with a little dilute HCl (1:3) and then with distilled water tili all acid is washed out; it is then torn in loose layers and dried at a low temperature in an air bath; when dry it can be easily shredded in fine strings, and is placed in a wide-mouth, glass-stoppered bottle. About two grams of asbestos are placed in each tube, packing it rather loosely; the tube is then weighed, a small narrow beaker being inverted over it on the scale pan. 5 ec. of milk are now drojped on to the asbestos from a 5 ee. fixed pipette, the baker again placed over the tube, and the weight of the 5 ec. of milk delivered +copper tube taken. The weight of the milk is ob- tained by difference. The tubes are then placed in a steam oven and heated at 100° CS. until they no longer decrease in weight, which will ordinarily take about three hours. Place ina desiccator until cold, and weigh; the difference between the weight of the tube+milk and this last weight gives the water contained in the milk, which is then calculated in per cent. of the quantity of milk weighed out. Chemical Analysis of Milk and Its Products. 221 Example: Weight of tube+beaker-+milk.... 29.3004 grams. Weight of tube-+beaker.......... 24.1772 grams. Milk weighed out.......... 5.1232 grams. Weight of tube+beaker+milk.... 29.3004 grams. Weight of tube+beaker+milk,dry 24.9257 grams. Weight of water........... 4.3747 grams. Per cent. of water in milk—* 2 100 — 85.39 per cent. Note. The per cent. of total solids in milk is often viven, instead of that of water; this may he readily ob- tained by subtracting the weight of the empty tube from that of the tube filled with milk solids, and finding the per cent. of the milk weighed out which this differ- ence makes. In the above example, the weight of milk solids thus is 24.9257—24.1772—.7485 gram, and the per cent. of total solids in the milk—14.61 per cent. 252. Alternate method. Five ce. of milk are measured out on a weighed flat porcelain dish (50-60 mm. in diameter; porce- lain covers will answer the purpose well if the handle be broken off or ground off level on an emery wheel); this is weighed rap- idly; two or three drops of 30 per cent.-acetiec acid are added, and the dish is dried in a steam oven at 100° C. until no further loss in weight occurs. After cooling in a desiccator, the weight of the milk solids is obtained, and by calculation as before, the per cent. of water or total solids in the milk. 253. ec. Fat. The dried tubes from the water deter- mination are placed in Caldwell extractors and con- nected with weighed, numbered glass flasks (capacity, 2-3 oz.) ; the extractors are attached to upright Liebig condensers and the tubes extracted with pure ether, free from water, alcohol or acid, until all fat is dis- solved; 4-5 hours’ extraction is sufficient for whole milk; in case of samples of skim milk it is well to con- 222 Testing Mik and Its Products. tinue the extraction for 8 hours. The ether is then re- covered by distillation, and the flasks dried in a steam oven until constant weight; after cooling they are weighed and the amount of fat contained in the quan- tity of milk originally weighed into the tubes is thus ascertained, and the per cent. present. jn the milk cal- culated. : Kaample: «Weight of ~flask--fats.. 2. co < 2% 15.8039 grams. Weieht ot: flagk oo hrcn. ste nee ano 15.5171 grams. Weoreht OL at at.c: Smee hi-veoy ate .2868 gram. Malk = weighed: Outs ci taieo n2 od weer 5.1232 grams. ; . . -29 8 < 100 Per cent. of fat in milk=-8*1—5 60 per cent. 5.1232 254. The Gottlieb method for the determination of fat... 10 ce. of milk are measured into a glass eyl- inder, 34 inch in diameter and about 14 inches long (a 100 ec. burette or a Eudiometer tube will do); 1 ee. cone. ammonia is added and mixed thoroughly with the milk; the following chemicals are next added in the order given: 10 ec. of 92 per cent. alcohol, 25 cc. of washed ether, and 25 ce. petroleum ether (boiling pt., below 80° C.), the cylinder being closed with a moist- ened cork stopper and the contents shaken several times after the addition of each chemical. The cylinder is then left standing for six hours or more. The clear fat solution is next pipetted off into a small weighed flask, by means of a siphon drawn to a fine point (see fig. 6, loc. cit.), which is lowered into the fat solution to within 1% em. of the turbid bottom layer. After evaporating the ether solution in a hood, the flasks are dried in a steam oven 1Landw. Vers. Sta., 40 (1892), pp. 1-27. The method is also spoken of as the R6ése-Gottlieb method. Chemical Analysis of Milk and Its Products. 223 for two to three hours, and weighed. This method is applicable to new milk, skim milk, butter milk, whey, cream, cheese, condensed milk and milk powder, but has been found of special value for determining fat in skim milk, butter milk, cheese, and condensed milk. In the ease of products high in fat, a second treatment with 10 ec. each of ether and petroleum is advisable in order to recover the last traces of fat. 255. d. Casein and albumen. The sum of these com- ponents is generally determined by the Kjeldahl method. 5 ee. of milk are measured carefully into a 800 cc. Jena flask, 20 cc. of concentrated sul- furic acid (C. P.; sp. gr.; 1.84) are added, and .7 gram of mercuric oxid (or its equivalent in metallic mer- cury); the mixture is then heated over direct flame until it is straw-colored or perfectly white; a few crys- - tals of potassium permanganate are now added till the color of the liquid remains green. All the nitrogen in the milk has then been converted into the form of am- monium sulfate. After cooling, 200 ec. of ammonia- free distilled water are added, 20 cc. of a solution of potassium sulfid (containing 40 grams sulfid per liter), and a fraction of a gram of powdered zine. A quan- tity of semi-normal HCl-solution, more than sufficient to neutralize the ammonia obtained in the oxidation of the nitrogen in the milk, is now carefully measured out from a delicate burette (divided into =) ec.) into a re- ceiving flask and the flask ecnnected with a distillation apparatus. At the other end, the Jena flask containing 1¥Fresenius’ Zeitschrift, 22, p. 366; U. S. Dept. Agr., Bur. of Chem., Bull. 107, p. 5. 224 Testing Milk and Its Products. the watery solution of ammonia sulfate is connected, after adding 50 ce. of a concentrated soda. solution (1 pound ‘‘pure potash’’ dissolved in 500 ce. of distilled water and allowed to settle) ; the contents of the Jena flasks are now mixed and heated to boiling, and the distillation is continued for forty minutes to an hour, until all ammonia has been distilled over. The excess of acid in the Erlenmeyer receiving-flask is then accurately titrated back by means of a tenth- normal standard ammonia-solution, using a cochineal- solution! as an indicator. From the amount of acid used, the per cent. of nitrogen is obtained; and from it, the per cent. of casein and albumen in the milk by mul- tiplying by 6.25.2, The amount of nitrogen contained in the chemicals used is determined by blank experiments and deducted from the nitrogen obtained as described. Example: The weight of 5 ce. of milk (as obtained in deter- mining the water in the milk) was 5.1465 grams. 5 cc. of stand. ard HCl are added to the receiver, and 1.55 ce. of + alkali solution are used in titrating back the excess of acid. 1.55 ec. of ~ alkali = 1°? —31 ee. y acid solution; the ammonia dis- tilled over therefore neutralized 5.00—.31=4.69 ce. acid. By blank trials it was found that the reagents used furnished an equivalent of .02 cc. acid in the distillate; this quantity sub- tracted from the acid-equivalent of the nitrogen of the milk leaves 4.67 cc. 1 ec. semi-normal HCl-solution corresponds to 7 milligrams or .007 gram of nitrogen; 4.67 ce. -\ HCl therefore represents .03269 gram of nitrogen. This quantity of nitrogen was obtained from the 5.1465 grams of milk measured out; the milk therefore contains 03269 X 100 5.1465 .635 X6.25=3.97 per cent. of casein and albumen. =.635 per cent. of nitrogen, and 1Sutton, Volumetric Analysis, 4th edition, p. 31. 2 The factor 6.30 or 6.387 is more correct for the albuminoids of milk, but has not yet been generally adopted (p. 15, foot note). Chemical Analysis of Milk and Its Products. 220 256. Casein and albumen may be determined sepa- rately by Van Slyke’s method;' 10 grams of milk are weighed out and diluted with about 90 ec. of water at 40°-42° CG. 1.5 ec. of a 10 per cent. acetic-acid solution are then added; the mixture is well stirred with a glass rod and the precipitate allowed to settle for 3 to 5 min- utes. The whey is decanted through a filter and the precipitate washed two or three times with cold water. The nitrogen is determined in the filter paper and its contents by the Kjeldahl method; blank determinations with the regular quantities of chemicals and the filter paper used are made, and the nitrogen found therein deducted. The per cent. of nitrogen obtained multi- plied by 6.25 gives the per cent. of casein in the milk. 257. Albumen is determined in the filtrate from the easein-precipitate; the filtrate is placed on a water bath and heated ta boiling for a period of from ten to fifteen minutes. The washed precipitate is then treated by the Kjeldahl method for the determination of nitro- gen; the amount of nitrogen multiplied by 6.25 gives the amount of albumen in the milk. The difference be- tween the total nitrogenous components found by the Kjeldahl method, and the sum of the casein and the albumen, as given above, is due to the presence in milk of a third class of nitrogen compounds (18).? 257a. The protein of milk may also be obtained by calculation from the total solids of the milk by the use of the following formula worked out by Mr. Geo. A. 1 Bulletin 107, p. 117, Bur. of Chem., U. S. Dept. of Agriculture. 2 Volumetric determinations of casein in milk have been proposed by Van Slyke and Bosworth (Geneva, N. Y.) expt. station, tech.. bull. 10) and by Hart (Wis. expt. station, research bull. 11). 15 226 Testing Milk and Its Products. Olson’: P—T—+ The results obtained by this formula are quite satisfactory. If we assume that .8 of the milk protein is casein, this component can also be obtained from the solids of the milk by a simple caleula- tion by the use of the preceding formula. 258. Hart’s test for casein in milk. The following test for casein in milk has been published by the Wis- consin experiment station.” Two ce. of chloroform, 20 ce. of a .25 per cent. solu- tion of acetic acid, and 5 cc. of milk (both these latter of a temperature of about 70° F.) are measured into small tubes of special construction holding about 35 cce., the lower ends of which are narrow and eraduated to 1 cc. The mixture is shaken for 10 to 20 seconds and the tubes then whirled 714 or 8 minutes in a ecentri- fuge of 15 inches diameter, making 2000 revolutions per minute. (The use of a metronome is recommended to facilitate the control of the speed.) After whirling, the tubes are taken out of the centrifuge and allowed to stand for 10 minutes, and the percentage of casein read off directly from the scale on the lower end of the tubes, each division of which represents .2 per cent. of casein when 5 cc. of milk are measured out. The test ealls for considerable nicety of manipulation, but ap- pears to give reliable results when the directions given are strictly followed.® 259. e. Milk sugar is generally determined by differ- ence, the sum of fat, casein and albumen (total NX6.25), 1 Journ. Ind. and Hng. Chemistry, I, 1909, p. 253. 2 Report 24, p. 117: “A simple method for the estimation of casein in cow’s milk.’’ ‘3 See also Circ. 10, Wis. expt. sta., Operating the casein test at cheese factories. Chemical Analysis of Milk and Its Products. 227 and ash, being subtracted from the total solids. It may be determined directly by means of a polariscope, or eravimetrically by Fehling’s solution; only the former methcd, as worked out by Wiley,’ will be given here. The specific gravity of the milk is accurately deter: mined, and the following quantities of milk are meas- ured out by means of a 100 ee. pipette graduated to .2 ec. (or a 64 cc. pipette made especially for this purpose, with marks on the stem between 63.7 and 64.3 ec.), ac- - eording to the specific gravities given: 1.026, 64.3 ec.; 1.028, 64.15 ec.; 1.080, 64.0 ec.; 1.032, 63.9 ec.; 1.034, 63.8 ec.; 1.036, 63.7 ec. These quantities refer to the Schmidt-Haensch half-shadow polariscopes, standard- ized for a normal weight of 26.048 grams of sugar. The milk is measured into a small flask graduated at 100 ee. and 102.6 ec.; 30 ec. of mercuric-iodid solution (pre- pared from 33.2 grams potassium iodid, 13.5 grams mer- curic chlorid, 20 ec. glacial acetic acid and 640 ec. water) are added; the flask is filled to 102.6 ec. mark with distilled water, the contents mixed, filtered through a dry filter, and when the filtrate is perfectly clear, the solution is polarized in a 200 millimeter tube. The reading of the scale divided by 2, shows the per cent. of lactose (milk sugar) in the milk. Take five readings of two different portions of the filtrate, and average the results. 260. f. Ash. About 20 ec. of milk are measured into a flat-bottom porcelain dish and weighed ; about one-half of a ee. of 30 per cent.-acetic acid is added, and the milk first dried on water bath and then ignited in a 1 Agricultural Analysis, III, p. 275; Am. Chem. Jour., 6, p. 289 et seq. 228 Testing Milk and Its Products. muffle oven at a low red heat. Direct heat should not be applied in determining the ash in milk, since alkali chlorids are likely to be lost at the temperature to which milk solids have to be heated to ignite all organic carbon. Example: Weight of porcelain dish+milk.... 49.0907 grams. Weight of porcelain dish......... 28.3538 grams. Weight. of. milk Sceus ee 20.7369 grams. Weight of dish-++milk, after ignition 28.5037 grams. WY G2 Hi A5G bee GIS He sien serrata tenets 28.3538 grams. Weight of milk ash......... .1499 gram 1499 100__ Per cent. of ash=-—~——-—.72 per cent. 20.7369 The residue from the determination of solids by the Alternate Method given (252) may also be used for the - ash determination. B.—CREAM, SKIM MILK, BUTTER MILK, WHEY, CoNn- DENSED MILK. 262. The analysis of these products is conducted in the same manner as in case of whole milk, and the same constituents are determined, when a complete analysis is wanted. Skim milk, butter milk, and whey con- tain relatively small quantities of solids, and espe. cially of fat, and it is, therefore, well to weigh out a larger quantity than in ease of whole milk; if possible, toward 10 grams. The acidity of sour milk and butter milk must be neutralized with sodium carbonate pre- vious to the drying and extraction, as lactic acid is solu- ble in ether and would thus tend to increase the ether- extract (fat), if not combined with an alkali previous to the extraction. A Chemical Analysis of Milk and Its Products, 229 - 263. Specific gravity of butter milk. The specific gravity of butter milk (as well as of sour or loppered milk) is deter- mined by Weibull’s method; a known volume of the milk is mixed with a certain amount (say 10 per cent.) of ammonia of a definite specific gravity, and the specific gravity of the liquid determined after thorough mixing and subsequent standing for an hour. If A designate the volume of butter milk taken, B that of ammonia, and C that of the mixture; and if furthermore S designate the specific gravity of the butter milk, s, that of the ammonia, and s, that of the mixture, we have Cse— Bs A _ Klein’ has modified this method by weighing the liquids, thus securing greater accuracy; 22 to 24 per cent.-ammonia is used, one-tenth as much being taken as the amount of milk weighed out. The results come uniformly .0005 too high, and this correc- tion should always be made. The following formula will give the specific gravity of the milk, which in case of careful work will be accurate to one-half lactometer degree; if the letters given above designate weights (instead of volumes as before) and specific gravities of the liquids, respectively, we have 264. Condensed milk. The same methods are, in gen- eral, followed in the analysis of condensed milk as with whole milk. Condensed milk is preferably diluted with five times its weight of water prior to the analysis, both because such a solution can be more easily handled than the undiluted thick condensed milk, and the errors of analysis are thereby reduced, and because the fat is not readily extracted except when the milk has been 1 Milchzeitung, 1896, p. 656; see also De Koningh, Analyst, 1899, p42. 230 Testing Milk and Lis Products. diluted.1 The same constituents are determined as in ease of whole milk, viz., solids, fat, casein and albumen, ash, milk sugar, and cane sugar (if any has been added to the milk). ‘The cane sugar is determined by the dif- ference between the solids not fat and the sum of the casein, albumen, milk sugar and ash; if the student has a knowledge of the manipulation of the polariscope and has had experience in gravimetric sugar analysis, the milk sugar is determined gravimetrically, and the cane sugar by the difference between the polariscope reading after inversion and the milk sugar present. The specific gravity of condensed milk may be deter- mined by a method similar to that of McGill. 50 gr. of the thoroughly mixed sample are weighed into a tared beaker and washed with warm water into a 250 ee. flask, cooled to 60°, filled to the mark and carefully mixed. The specific gravity of this solution (a) is then taken and the original density is calculated by means of the following formula: Sp. gr. of condensed milk—=—1_ —oa Concentration. The extent of concentration of con- densed milk may be determined approximately by the formula devised by McGill (loe. cit.) : Concentration (c)==28_ a1S1 where a and s designate the solids not fat and specific gravity, respectively, of the condensed milk, and a, and s, the corresponding data for the milk used. If s,= 1A second extraction following leaching and subsequent drying of the tubes is necessary to extract all the fat in condensed milk; see Bull. 104, Bur. of Chem., U. S. Dept. of Agr., p. 102 and 154. 2 Bulletin 54, Laboratory Inland Rev. Dept., Ottawa, Canada. . Chemical Analysis of Milk and Its Products. 281 1.030 and a,=9 per cent., then aS gives the con- centration. C.—BuTTER. 265. Sampling. A four- to eight-ounce sample of butter is melted in a tightly-closed pint fruit jar, shaken vigorously and cooled until the butter is hard- ened, the jar being shaken vigorously at short intervals during the cooling so as to keep the water of the butter evenly distributed in the mass (102). 266. a. Determination of water. Small pieces of butter (about 2 grams in all) are taken from the sam-- ple by means of a steel spatula and placed in glass tubes, seven-eighths of an inch in diameter and two and a half inches long, closed at the bottom by a layer of stringy asbestos, and filled two-thirds full of asbestos prepared as for milk analysis (252). The tubes are dried at 100° C. in a steam oven, until no further loss in weight takes place, and are then cooled and weighed. The loss in weight shows the per cent. of water present. 267. b. Fat. The tubes are placed in Caldwell ex- tractors and extracted for four hours with anhydrous ether; the ether is then distilled off, and the flasks dried in the steam bath and weighed, the increase in weight giving the fat in the sample of butter weighed out. 268. c. Casein. 10 grams of butter are weighed into a small beaker provided with a lip, and treated twice with about 50 ec. of gasoline each time; the solution is filtered off, and the residue transferred to a filter and dried; its nitrogen content is then determined by the Kjeldahl method (255). The nitrogen in the filter and 232 Testing Milk and Its Products. the chemicals used is determined by blank trials and- deducted. The nitrogen multiplied by 6.25 gives the casein in the butter. 269. d. Ash. (1) 10 grams of butter are weighed into a porcelain dish and treated twice with gasoline, as in the preceding determination; the solution is filtered through an ash-free (quantitative) filter, and the filter when dry is transferred to the dish. The dish is heated ‘in an air-bath for half an hour and then placed in a muffle oven, where the contents are burnt to a lght grayish ash; the dish is now cooled in a desiccator and weighed. The difference between this weight and that of the empty dish gives the amount of ash in the butter weighed out. 270. (2) About two grams of butter are weighed into a small porcelain dish, half filled with stringy asbestos; the dish is dried for half an hour in the water oven, and the fat then ignited with a match, the asbestos fibre serving as a wick. When the flame has gone out, the dish is placed in a muffle oven, and the residue carefully burnt to a grayish ash. After cooling, the dish is weighed, and the per cent. of ash in the butter caleu- lated as under method 1. 271. Complete analysis of butter in the same sam- ple. About 2 grams of the butter are weighed into a platinum gooch half filled with stringy asbestos, and dried in a steam oven at 100° C. to constant weight, eooled and weighed. The difference gives water in the sample. The gooch is then treated repeatedly with small portions of gasoline, suction being applied, and again dried in the water oven, cooled, and weighed; the Chemical Analysis of Milk and lis Products. 233 fat in the sample is obtained from the difference be- tween this and the preceding weight. The gooch is then carefully heated at a low red heat until a light grayish ash is obtained; this operation is preferably done in a muffle oven to avoid a loss of alkali chlorids. The loss in weight gives the casein in the sample weighed out, and the increase in the weight of the gooch over that of the empty gooch with asbestos, gives the ash (mainly salt) of the butter. The salt in the ash may be dissolved out by hot water, and the chlorin content of the solution determined by means of a stand- ard silver-nitrate solution, using potassium chromate as an indicator (278). 272. Creamery methods of estimating water in butter. A number of different methods have been pro- posed of late years for the rapid esti- mation of water in butter, the object sought being to en- able a buttermaker . to ascertain the water content of his butter without much Fic. 58a. Balance for weighing butter trouble or delay, ‘™ ‘"?® and by using such simple apparatus as he is likely to have in the creamery or can easily procure at a low price. The subject of controlling the per cent. of water in butter has become more important than was earlier the case, through the passage of the pure-food law, and the promulgation of government food standards in 234 Testung Milk and Its Products. 1906 (805) ; these measures have rendered the question of guarding against an excessive water content in the butter one of the greatest importance to all butter- makers. Most of the methods suggested for this purpose are essentially the common method of chemical analysis modified to meet the demands of every-day factory con- ? ditions. References to descriptions of the dif- ferent methods pro- posed are given below, and a few that are now used in factories and outside of chemical lab- (700 oratories, are described Fic. 58b. Scale for weighing but- , : ter for testing. in detail. In all these rapid methods of determining the water content in butter, the sample of butter must be pre- pared so as to accurately represent the lot of butter sampled (see 102), and must be carefully weighed on a delicate scale (see figures 58a and b). The directions, in so far as they are given in detail in the following, therefore, presuppose that a carefully prepared, fair sample has been obtained in all cases. 273. Among the methods proposed for the rapid de- termination of the per cent. of water in butter that are adapted for use in creameries may be mentioned: Richmond’s method,! Carroll’s tester,? Geldard’s but- 1 Dairy Chemistry, p. 252. 2Dept. of Agr., Ottawa, Dairy Com’r Branch, bull. 6, pp. 10-11. Chemical Analysis of Milk and Its Products. 235 ter tester,: the Irish ‘‘common sense butter and cheese test,’? Dean’s,? Gray’s,? Pitrick’s,* the Wisconsin high pressure oven method,’ the Ames method,® and the Cornell moisture test.’ The following four of these methods will be briefly described: 274. a. Gray’s method. ‘This method, in- vented by Prof. C. E. Gray, formerly of the Dairy Division of the U. S. Dept. of Agri- culture, was published in 1906; the method consists of heating ten grams of butter in a special flask of about 70 cc. capacity (see fig. 59) with 6 ec. of ‘‘amyl reagent’’ (five parts of amyl acetate and one part amyl valerianate). The water is boiled out of the butter by heating over direct flame, and together with some of the reagent, is condensed, cooled, and meas- ured in a graduated tube attached to the flask. The accompanying illustration shows the ar- rangement of the distilling flask and the gradu- _ ated tube in which the water is measured. For details of manipulation, reference is made to in Gray’ ae : ; method. the original publication, or to the files of our dairy press published during 1906-7.° 1 Dept. of Agr., Ottawa, Dairy Com’r Branch, bull. 14, pp. 6-8. 2 Ontario Agr. College, rept. 1906, p. 120. 8 Cire. 100, Bur. An. Ind., U. S. Dept. of Agr. 4 Journal Am. Chem. Soc., 28, 1906, p. 1611. 5 Bull. 154, Wis. experiment station. 6 Bull. 97, Iowa experiment station. 7 Bull. 281, Cornell experiment station. 8B. g., New York Produce Review, Jan. 16, 1907; American Cheese Maker, Jan., 1907. 236 Testing Milk and Its Products. A modification of the Gray method has been proposed by Mitchell and Walker of the Kingston (Ont.) Dairy School, and described as the Mitchell-Walker test. 275. Patrick’s method. Ten grams of butter are accurately weighed into a 800 ce. aluminum beaker (about 3 inches tall and 2 inches in diameter) ; this is held by means of a hand clamp over the flame of the alcohol lamp or a gas burner (see fig. 60) and very carefully heated until all the water is expelled. The beaker is then cooled by sinking it to the rim in water of 50° to 60°, wiped dry, and the loss in weight ealeulated as water. If ten grains of butter weighed tee (0. Aue te 8.45 grams after heating, tet- the loss in weight of 1.55 grams represents 15.5 per cent. of the weight of the sample, and the butter there- fore contained 15.5 per cent. of water.? The results ob- tained by this method seldom vary more than .2 per cent. from those of chemical analysis, and often less than .1 per cent. when proper care in sampling and weighing has been taken. A few points need special attention in using this 1 Bull. 167, Dairy Branch, Ont. Dept. of Agriculture. 2A convenient table showing per cents of moisture in butter direct when 9 to 10.15 grams are weighed out, has been published by the Copenhagen experiment station (62nd report; see N. Y. Produce Rev.. 1908, p. 530). Chemical Analysis of Milk and Its Products. 237 method: First, care must be taken not to heat the beaker too fast so that spattering occurs; there is not so much danger from this source when an alcoho! lamp is used as with a gas burner, which easily raises the tem- perature too high, causing a fine spray of material to be thrown about, and thus giving too high results for water content. Second, it is important to discontinue the heating at the exact point when all the water has been driven off and before burning of the non-fatty solids (casein, milk sugar, and organic acids) occurs, as indicated by a slight darkening in color. It is not necessary to cool the beakers in water, but they can be left to cool in the air. The determination of water in butter by this method can be finished in ten minutes -or less by an experienced operator. The Trish test is similar to the method described in the preceding, differing from the same mainly in the shape of the aluminum dishes used. Modifications of this test have also been worked out by the Iowa and Cornell experiment stations, which are designed to pre- vent losses by spattering when the dish is heated. In the Ames method the aluminum dish containing the sample is heated with a paraffine bath, while in the Cor- nell test a thin sheet of asbestos is placed between the flame and the dish holding the samples. 276. Dean’s method. Three cc. of a melted sample of butter are placed in an ordinary ‘‘patty-pan’’ tin dish (about 214 inches in diameter and 1% inch deep) and accurately weighed; the dish is then placed in a steam oven provided with a pop safety valve, a steam 238 Testing Milk and Its Products. pressure gauge, and a thermometer. The oven used by Professor Dean of Guelph (Ont.) Dairy School, the originator of this method, was 6x8 inches. It was made of galvanized iron by a local tin-smith at a cost of about $5.00, exclusive of safety valve and steam gauge, and was made to withstand a pressure of about 10 pounds. After five or six hours’ drying in the oven, the samples of butter are ready to be weighed, and the loss gives the amount of water present therein. The average results obtained by this method with nine sam- ples of butter came within .13 per cent. of those found by chemical analyses. The same method is recommended by the author for determining the per cent. of water in curd or cheese. 277. The Wisconsin high-pressure oven method (see fig. 61). Either 10 or 50 grams of butter are weighed in a flat-bottomed tin or aluminum dish. This is placed in an oven heated by high pressure steam to a temperature of 240° to 280° F. The length of time re- quired to expel all the water from the butter will de- pend on the temperature of the oven and the diameter of the dish in which the butter is heated. If the dish is large enough to permit the butter to spread into a very thin layer and the temperature of the oven reaches 260° F., the water will be completely expelled in half an hour. Ovens of this construction have now been placed on the market by manufacturers of dairy supplies. A steam pressure of 60 lbs. and a tempera- ture of 280° F. may be obtained in such an oven; by employing the boiler pressure ordinarily used in a Chemical Analysis of Milk and Its Products. 239 creamery, temperatures of 240° to 260° may be easily obtained, The temperature thus reached is sufficient to dry the butter completely within an hour, provided pans large enough to spread the butter in a thin layer are used, If 10 grams of butter are used in making tests, a more delicate scale is necessary than when 50 grams are taken. There are other advantages in using as large a quantity as 50 grams of butter for making tests of water. First, a sample can be weighed out directly from a package. Second, ordinary tin basins at least 5 inches in diameter can be used for dry- ing the butter. Third, scales G- Gs with a graduated side beam and sensitive to .1 gram in- stead of those with smaller loose weights can be used for weighing the butter. (See figs. Fic. 61. The Wisconsin high- 58a and 58b.) pressure oven. ° ° ° ° ° ° 278. Creamery methods of estimating salt in butter. I. The ordinary volumetric method used in chemical laboratories for determining the salt content of butter has been adapted for work in the creamery by Prof. Sammis.1 5.1 grams of chemically pure nitrate crystals are dissolved in 250 ec. of water. Each ec. of this solution will represent 1 per ct. of salt when 17.6 cc. of the liquid are measured which is obtained by shaking 10 grams of butter with 250 ec. of clean, warm water. The silver nitrate solution is added from a 25 or 50 ce. burette divided into tenths — of a cubic centimeter. One or two drops of the usual indicator 1Cire. 14, Wisconsin expt. station. z 240 Testing Milk and Its Products. employed (1 oz. potassium chromate dissolved in 100 cc. of water) are added prior to the titration. II. The use of silver nitrate tablets for making standard solutions for volumetric determinations of salt in butter was proposed by Prof. A. Vivian and C. L. Fitch in 1901.1 The tab- lets have not been on the market during late years. 278a. Shaw’s test for fat and salt in butter. R. H. Shaw has devised a method for determining the per- centages of fat and salt in the same sample of butter which has considerable merit. For description of this method see Cire. 202, Bur. of Animal Ind., U. 8. Dept. of Agriculture. DETECTION OF ARTIFICIAL BUTTER. 279. Determination of the specific gravity of the fil- tered butter fat serves as a good preliminary test. A number of practical methods for the detection of artifi- cial butter have been proposed, but they are either worthless for the examination of samples containing a considerable proportion of natural butter, or give satis- factory results only in the hands of experts. The Reich- ert-Meissl method given in detail below is the standard method the world over, and the results obtained by it are accepted in the courts. | 280. Filtering the butter fat. The butter to be ex- amined is placed in a small narrow beaker and kept at 60° C. for about two hours. The clear supernatant fat is then filtered through absorbent cotton into a 200 ce. Erlenmeyer flask, taking care that none of the milky lower portion of the contents of the beaker be poured on the filter. In sampling the butter fat, it is poured 1 Wis. experiment station, report 17, pp. 98-101; Hoard’s Dairyman, February 15, 1901, “Uniform Salting of Butter.” Chemical Analysis of Milk and Its Products. 241 back and forth repeatedly from a small warm beaker into the flask, and the quantity wanted is then drawn off with a warm pipette. 281. Specific gravity. This is generally determined at 100° C. The method of procedure is similar to that described under milk (248). The picnometer (capacity about 25 ec.) is filled with dry filtered butter fat, free from air bubbles; the fat is heated for 30 minutes in a beaker, the water in which is kept boiling. On cooling, the weight of picnometer and fat is obtained, and by calculation as usual, the specific gravity of the fat. The specific gravity of pure natural butter fat at 100° C. ranges between .8650 and .8685, while artificial butter fat (i. e., fat from other sources than cow’s milk) has a specific gravity at 100° C. of below .8610, and gen-’ erally about .85. 282. Reichert-Meissl method (Volatile Acids.) 5.75 ee. of fat are measured into a strong 250 ee. weighed saponification flask, by means of a pipette marked to deliver this amount, and the flask when cool is weighed again. 20 ee. of a glycerol-soda solution (20 ec. of. soda solution (1:1) to 180 ec. of pure glycerol), are then added to the flask and the flask is heated over a naked flame or hot asbestos plate until complete saponification has taken place, as shown by the mixture becoming per- fectly clear. If foaming occur, the flask is shaken gently. : 135 ec. of recently-boiled distilled water are now added, drop by drop, at first, to prevent foaming, and when the solution is clear, cooled to about 70° C.; 5 ee. of dilute sulfuric acid (200 ee. cone. H,SO, per liter) are 16 249 Testing Milk and Its Products. added to the soap solution to decompose the soap into free fatty acids and glycerol. A few pieces of pumice stone (prepared by throwing the pieces at white heat into distilled water and keeping them under water until used) are added, the flask connected with a glass con- denser, heated slowly till boiling begins, and the con- tents then distilled at such a rate as will bring 110 ee. of the distillate over in as nearly thirty minutes as pos- sible. The distillate is mixed thoroughly and filtered through a dry filter; 100 ce. of the filtrate are poured into a 250 ce. beaker and titrated with a deci-normal barium-hydrate solution, half a cubie centimeter of phe- _ nolphtalein solution being used as an indicator. A blank test is made in the same manner as described, and the amount of alkali solution used deducted from the re- sults obtained with the samples analyzed. The number of cubic centimeters of barium-hydrate solution used is increased by one-tenth, and the so-called Reichert or Retchert-Meissl number thus obtained. The Reichert number for pure butter fat will ordi- narily come above 24 ec. and may go over 30 ce; butter fat from stripper cows will have a low Reichert num- ber. Pure oleomargarine will have a Reichert number of 1 to 2 ec.; and mixtures of artificial and natural but- ter will give intermediate numbers. TESTS FOR THE DETECTION OF OLEOMARGARINE OR RENO- VATED BUTTER. 283. The boiling test.1 A piece of butter of the size of a small chestnut is melted in an ordinary tablespoon 1 Patrick, Household tests for the detection of oleomargarine and renovated butter, Farmer’s Bulletin, No. 131. For detection and Chemical Analysis of Milk and Its Products. 248 (or a small tin dish) at a low heat, stirring with a splin- ter of wood. The heat is increased until as brisk a boil as possible, and after boiling has begun, the melted mass is stirred thoroughly two or three times, always shortly before boiling ceases. Oleomargarine and renovated butter will boil noisily, sputtering like a mixture of gerease and water when boiled, and will produce but little or no foam. Renovated butter produces usually a very small amount of foam, while genuine butter boils with less noise and produces an abundance of foam. 284. The Waterhouse test for distinguishing oleo- margarine and renovated butter.t Half fill a 100 ee. beaker with sweet skim milk (or distilled water), heat nearly to boiling and add 5 to 10 grams of butter or oleomargarine. Stir with a small wooden stick of about the size of a match until the fat is melted; the beaker is then placed in ice water, and the milk (or water) stirred until the temperature falls sufficiently for the fat to congeal. If oleomargarine, the fat can now be easily collected into one lump by means of the stick, while if genuine or renovated butter, the fat will granulate and ean not be so collected.” D.— CHEESE. For method of sampling, see par. 104. 285. a. Water. Five grams of cheese cut into very thin slices are weighed into a small porcelain dish filled about one-third full with freshly-ignited stringy asbes- examination of renovated or “process” butter, see also Cochran, Journ Frankl. Inst., 1899: p. 94: Analyst, 1899, p. 88. 1¥Warmers’ Bulletin No. 131, p. 7. 2¥For tests for artificial coloring matter in oleomargarine, see Circ. 629, Com. of Internal Rev., Treasury Dept. 244 Testing Milk and Its Products. tos; the dish is placed in a water oven and heated for ten hours. The loss in weight is taken to represent water. (See also Dean’s method for determining water in but- ter, curd and cheese, par, 276.) 286. b. Fat. About 5 grams of cheese are ground finely in a small porcelain mortar with about twice its weight of anhydrous copper sulfate, until the mixture is of a uniform light blue color and the cheese evenly dis- tributed throughout the mass. The mixture is trans- ferred to a glass tube of the kind used in butter analysis (263), only a larger size; a little copper sulfate is placed at the bottom of the tube, then the mixture containing the cheese, and on top of it a little extracted absorbent cotton or ignited stringy asbestos; the tube is placed in an extraction apparatus and extracted with anhydrous ether for fifteen hours. The ether is then distilled off, the flasks dried in a water oven at 100° C. to constant weight, cooled and weighed. The method is apt to give too low results and, therefore, not to be preferred to the Babeoek test for cheese (105). 287. c. Casein (total nitrogen 6.25). About 2 grams of cheese are weighed out on a watch glass and trans- ferred to a Jena nitrogen flask, and the nitrogen in the sample determined according to the Kjeldahl method (253); the percentage of nitrogen multiplied by 6.25 gives the total nitrogenous components of the cheese. 288. d. Ash. The residue from the water determina- tion is taken for the ash; it is preferably set fire to, in the same manner as explained under determination of ash in butter (270), before it is placed in the muffle oven and incinerated. The increase in the weight above Chemical Analysis of Milk and Its Products. 245 that of the empty dish-+-asbestos, gives the amount of ash in the sample weighed out. 289. e. Other constituents. The sum of the percent- ages of water, fat, casein and ash, subtracted from 100, will give the per cent. of other constituents, organic acids, milk sugar, etc., in the cheese. DETECTION OF OLEOMARGARINE CHEESE (‘‘FILLED’’ CHEESE. ) 290. About 25 grams of finely-divided cheese are ex- tracted with ether in a Caldwell extractor or a paper extraction cartridge; the ether is distilled off, and the fat dried in the water oven until there is no further loss in weight. 5.75 ce. of the clear fat are then meas- ured into a 250 ec. saponification flask and treated ac- cording to the Reichert-Meiss] method, as already ex- plained under Detection of Artificial Butter (282). TESTS FOR ADULTERATION OF MILK AND CREAM, 291. Use of the refractometer. The immersion re- fractometer furnishes a delicate apparatus for the de. tection of watered milk.? 100 ee. of milk and 2 ce. of 25% acetic acid are heated for twenty minutes at 70° C. This is then placed on ice for ten minutes and filtered.’ The refractometer reading of the clear filtrate is then taken at 20° C. If this reading is above 40 the mitk is not watered, while figures below 40 show adulteration by watering. 291a. The nitric acid test may prove useful as cor- roborative evidence that a sample of milk has been 1See Arb. Kais. Ges.-Amt., 14, 506-598. ? Leach, Food Analysis, 2nd ed., p. 168. See also Jr. Ind. and Eng. Chem., 1911, p. 44 and p. 573. 246 Testing Milk and Its Products. watered (126). Normal fresh milk does not contain nitrates, while common well-water, particularly on farms where precautions to guard against contamina- tion of the water supply have not been taken, in gen- eral contains appreciable amounts of nitrates, nitrites and ammonia compounds, and watered milk will, there- fore, in such cases also contain nitrates.1 The method for detection of small amounts of nitrates in milk, as given by Richmond? is as follows: Place a small quan- tity of diphenylamin at the bottom of a porcelain dish, and add to it about 1 ec. of pure H,SO, (conc.) ; allow a few drops of the milk serum (obtained by adding a little acetic acid to the milk and warming) to flow down the sides of the dish and over the surface of the acid. If a blue color develops in the course of ten minutes, though it may be faint, it shows the presence of nitrates ; after ten minutes a reddish-brown color is always de- veloped from the action of the acid on the serum. There should be no difficulty in detecting an addition of 10 per cent. of water to the milk by this test, if the water added contained 5 parts of nitric acid, or more, per 100,000. The following test for nitric acid is proposed by Mc- Kay and Bouska: About 5 ee. of milk is placed in a test tube. Some Kaniss’ reagent (about 1 part formal- dehyd in 500 ee. C. P. H,SO,) is poured down the side — of the tube so it will form a layer under the milk. If nitrates or nitrites are present, a violet ring will form at the place of contact. This is Hehner’s test for for- maldehyd reversed, see (304). igeannannt Deutsche viertenjanmececcun f. Off. Ges.-pfl., 15, p. 663. 2The Analyst, 1893, p. 272. Chemical Analysis of Milk and Its Products. 247 292. Besides by the methods given in the preceding (pp. 121-127), watering or skimming of milk may be de- tected by determining the specific gravity of a, the skim milk, b, the milk serum, and c, the whey. a. Specific gravity of skim milk. The milk is set in a flat porcelain or glass dish for 12 to 24 hours in a cold room; the layer of cream formed is then skimmed off, and the sp. gr. of the skim milk determined at 60° F. Skim milk has a sp. gr. of .002 to 0035 (2 to 3.5 lactometer degrees) above that of the correspond- ing whole milk; a smaller difference than this indicates that the milk was skimmed. If both skimming and watering had been practiced, the difference given above might be obtained, but the analysis of the milk would in such case easily disclose the adul- teration. b. Specific gravity of the milk serum. To 100 ec. milk 2 cc. of 20 per cent.-acetic acid are added, and the mixture heated in a covered beaker or closed flask for 5-10 min. on a water-bath at 55-65° C. After cooling, the milk serum is filtered off and its sp. gr. determined at 60° F. In case of pure milks, the sp. gr. of the milk serum (at 60°) will come above 1.0270. Serum from normal milk contains 6.3 to 7.5 per cent. solids and .22 to .28 per cent. fat; by the addition of 10 per cent. of water, the solids in the serum are lowered .3 to .5 per cent., and the sp. age 0005.2 c. Specific gravity of whey. 500 cc. of milk are warmed in water of 40-50° C. until its temperature is 35° C.; one-half ce. of rennet extract (12-15 drops) is added, and the milk stirred thoroughly. After allowing the curd to solidify for 10 minutes, it is cut and the whey filtered off through several layers of cheese cloth. The whey must be clear; it is cooled to 60° F. and its Sp. gr. determined. The sp. gr. of whey from normal milk ob- tained in the manner given will range between 1.027 and 1.031. A sp. gr. of 1.026 or below indicates watering. An addition of 4 per cent. of water lowers the sp. gr. of the whey about 1 lac- tometer degree.” 1 Konig, Menschl. Nahrungsmittel, Il, p. 276. *Siats, Unters. landw. wicht. Stoffe, p. 88. — 248 Testing Milk and Its Products. 293. Detection of coloring matter. Milk which has been watered or skimmed, or both, is sometimes further adulterated by unscrupulous milk dealers by an addi- tion of a small quantity of cheese color; this will mix thoroughly with the milk, and, if added judiciously, will impart a rich cream color to it. The presence of for- eign coloring matter in milk is easily shown by shaking 10 ec. of the milk with an equal quantity of ether; on standing, a clear ether solution will rise to the surface; if artificial coloring matter has been added to the milk, the solution will be yellow colored, the intensity of the color indieating the quantity added; natural fresh milk will give a colorless ether solution. } A method gived by Wallace’ is claimed to detect one part of coloring matter in 100,000 of milk. Inorganic coloring matter like chromates and bi-chro- mates have, although fortunately rarely, been used to impart a rich color to adulterated milk or poor cream. Chremates may be detected by the reddish yellow color produced when a little 2 per cent.-silver nitrate solution is added to a few cubic centimeters of the milk. 294. Detection of pasteurized milk or cream. Prof. Storch, of Copenhagen, Denmark,? in 1898, published a simple method for ascertaining whether milk, cream, or other dairy products have been heated to at least 176° F. (80° C.). The test is made-as follows: A teaspoonful of the milk is poured into a test tube, and 1 drop of a weak solution of peroxid of hydrogen (2 per cent.) and 2 drops of a paraphenylenediamin-solu- 1N. J. Dairy Commissioner, report 1896, p. 36. 240th report, Copenhagen experiment station. Chemical Analysis of Mik and Its Products. 249 tion (2 per cent.) are added. The mixture is then shaken; if a dark violet color appears at once, the milk has not been heated, or at any rate not beyond 176° F. If a sample of butter is to be examined, 25 grams are placed in a small beaker and melted by being placed in water of 60° C. The clear butter fat is poured off, and the remaining liquid is diluted with an equal volume of water. The mixture thus obtained is examined as in ease of milk. Guaiacum tincture has also been recommended for the detection of pasteurized cream or milk; this solution is easily obtained, keeps well, and is convenient to use (McKay). 295. Boiled milk. The preceding tests will serve to distinguish between raw and boiled milk, and also to ascertain if milk has been adulterated with diluted con- densed milk. To what extent such an adulteration can be practiced without being detected by this or similar tests, has not been determined, but if a control test be made at the same time with a sample of milk of known purity, a small admixture of boiled (or diluted con- densed) milk can doubtless be detected.* -296. Gelatine in cream. This method of adultera- tion is sometimes practiced in the city cream trade, to impart stiffness and an appearance of richness to the eream. To detect the gelatine, a quantity of the sus- pected cream is mixed with warm water, and acetic acid is added to precipitate the casein and fat (1.5 cc. of 10 per cent.-acetic acid per 10 ce. of cream is sufficient). 1See also Siats, Unters. landw. wicht. Stoffe, p. 60, and Molkerei- Ztg. (Hildesheim), 1899, p. 677. 250 Testing Milk and Its Products. The precipitate is filtered off, and a few drops of a strong tannin solution are added to the clear filtrate. Pure cream will give a slight precipitate, while in the presence of gelatine a copious precipitate will come down. The picric-acid method has also been proposed for the detection of small quantities of gelatine in cream.’ 297. Starch in cream. Starch is mentioned in the dairy literature as an adulterant of milk and cream. It is doubtful, however, if it is ever used for this purpose at the present time. In the case of ice-cream, on the other hand, a small quantity of corn starch is often added to thicken the milk used. It may in such a ease be readily detected by means of the iodin reaction. A solution of iodim will produce a deep blue color in the presence of starch; a small amount of iodin is taken up by the cream before-the blue coloration appears. 298. Macroscopic impurities (particles of hay, litter, woolen or cotton fibres, dung, etc.). These impurities may be separated by repeated dilution of the milk with pure distilled water, leaving the mixture undisturbed for a couple of hours each time before the liquid is syphoned off. When the milk has been entirely re- moved in this manner, the residue is filtered off, dried and weighed. A quart of milk or cream should not give any visible sediment on standing for several hours. A simple and striking method of showing dirt in milk has been suggested by Gerber. About a pint of milk is poured into an inverted bottomless long-necked 1The Analyst, 1897, p. 320. Chemical Analysis of Milk and Its Products. 251 bottle, over the mouth of which a piece of cotton is placed. The milk will filter through, leaving the dirt on the cotton, which is then removed and can be shown to the producer of the milk.’ A modification of the apparatus used has been de- scribed in publications of the Wisconsin experiment station.” DETECTION OF PRESERVATIVES IN DatrRy PRODUCTS. 299. a. Boracic acid (borax, borates, preservaline, etc.). 100 ce. of milk are made alkaline with a soda or potash solution, and then evaporated to dryness and incinerated. The ash is dissolved in water to which a little hydrochloric acid has been added, and the solu- tion filtered. A strip of turmeric paper moistened with the filtrate will be colored reddish brown when dried at 100° C. on a watch glass, if boracie acid is present. If a little alcohol is poured over the ash to which con- centrated sulfuric acid has been added, and fire is set to the alcohol, this will burn with a yellowish green tint, especially noticeable if the ash is stirred with a glass rod and when the flame is about to go out. 300. The following modification of the first test given is said to show the presence of only a thousandth of a grain of borax in a drop of milk (about .15 per cent.) :° Place in a porcelain dish one drop of milk with two drops of strong hydrochloric acid and two drops of saturated turmeric tincture; dry this on the water bath, cool and add a drop of ammonia by means of a glass rod. A slaty blue color changing to green is produced if borax is present.* 1 Hoard’s Dairyman, Nov. 29, 1907. _ 2Bull. 195 and Circular 41. 3N. J. Dairy Commissioner, report, 1896 p. 36. #See also par. 151. 252 Testing Milk and Its Products. 301. b. Bi-carbonate of soda. 100 ec. of milk to. which a few drops of alcohol are added, are evaporated and carefully incinerated; the proportion of carbonic acid in the ash as compared with that of milk of known purity is determined. If an apparatus for the deter- mination of carbonie acid is available, like the Scheibler apparatus, etc., the per cent. of carbonic acid per gram of ash (and quart of milk) can be easily ascertained. Normal milk ash contains only a small amount of ear- bonic acid (less than 2 per cent.), presumably formed from the citric acid of the milk in the process of incin- eration. The following qualitative test is easily made: To 10 ec. of milk add 10 ee. of alcohol and a little of a one per cent. solution of rosolic acid (corallin). Pure milk will give a brownish yellow color; milk to which soda has been added, a rose red color. A control experiment with milk of known purity should be made. 302. ec. Fluorids. 100 ec. of milk are evaporated in a platinum or lead crucible, and incinerated; the ash is made strongly acid with concentrated sulfurie acid. If fluorids are present hydrofluoric acid will be generated on gentle heating and will be apparent from its etching a watch glass placed over the crucible. 303. d. Salicylic acid (salicylates, etc.). 20 ee. of milk are acidulated with sulfuric acid and shaken with ether; the ether solution is evaporated, and the residue treated with alcohol and a little iron-chlorid solution; 1 Chromates in dairy products may be readily determined by the use of a silver-nitrate solution, see Molkerei-Ztg. (Berlin) 1899, p. 603. Chemical Analysis of Milk and Its Products. 253 -a deep violet color will be obtained in the presence of salicylic acid. 304. e. Formaldehyde (a forty-per cent. solution in water). The following method by Hehner is stated to show the presence of one part of formaldehyde in 200,000 parts of milk: the milk is diluted with an equa! volume of water, and strong H,SO, (sp. gr. 1.82-1.84) is added. A violet ring is formed at the junction of the two liquids if formaldehyde is present; if not, a slight green- ish tinge will be seen. The violet color is not obtained with milk containing over .05 per cent. formaldehyde.’ The same color reaction is obtained in the Babcock test and is easily recognized by persons familiar with milk testing when their attention has once been called to the characteristic color. An adulteration of milk with formaldehyde may be readily detected by the following method, which will show the presence of only a trace of formaldehyde in the milk. 5 ce. of milk is measured into a white porce- lain dish, and a similar quantity of water added. 10 ec. of HCl containing a trace of Fe,Cl, is added, and the mixture is heated very slowly. If formaldehyde is _ present, a violet color will be formed. 1Chem. News, 1896, No. 71; Milchzeitung, 1896, 491; 1897, 40, 667; The Analyst, 1895, 152, 154, 157; 1896, 285. 305. GOVERNMENT STANDARDS OF PURITY FOR: MILK“ AND- iS PRODUCES: a. MILKS. 1. Milk is the fresh, clean, lacteal secretion obtained by the complete milking of one or more healthy cows, properly fed and kept, excluding that obtained within fifteen days before and ten days after calving, and contains not less than eight and one half (8.5) per cent. of solids not fat, and not less than three and one-quarter (3.25) per cent. of milk fat. 2. Blendid milk is milk modified in its composition so as to have a definite and stated percentage of one or more of its con stituents. 3. Skim milk is milk from which a part or all of the cream has been removed and contains not less than nine and one-quarter (9.25) per cent. of milk solids. 4. Pasteurized milk is milk that has been heated below boil- ‘ng but sufficiently to kill most of the active organisms present and immediately cooled to 50° Fehr. or lower. 5. Sterilized milk is milk that has been heated at the tem perature of boiling water or higher for a length of time suffi- cient to kill all organisms present. . 6. Condensed milk, evaporated milk,is milk from which a considerable portion of water has been evaporated and contains not less than twenty-eight (28) per cent. of milk solids, of which not less than twenty-seven and five-tenths (27.5) per cent. is milk fat. 7. Sweetened condensed milk is milk from which a consid- erable portion of water has been evaporated and to which sugar (sucrose) has been added, and contains not less than twenty- eight (28) per cent of milk solids, of which not less than twenty-seven and five-tenths (27.5) per cent. is milk fat. 1 Circular No. 19, Office of the Secretary, U. S. Dept. of Agriculture, June 26, 1906. Government Standards of Purity. 255 8. Condensed skim milk is skim milk from which a consid- erable portion of water has been evaporated. 9. Buttermilk is the product that remains when butter is re- moved from milk or cream in the process of churning. 10. Goat’s milk, ewe’s milk, etc., are the fresh, clean, lac- teal secretions, free from colostrum, obtained by the complete milking of healthy animals other than cows, properly fed and kept, and conform in name to the species of animal from which they are obtained. b. CREAM, 1. Cream is that portion of milk, rich in milk fat, which rises to the surface of milk on standing, or is separated from it by centrifugal force, is fresh and clean and contains not less than eighteen (18) per cent. of milk fat. 2. Evaporated cream, clotted cream, is cream from which a considerable portion of water has been evaporated. Cc. MILK FAT OR BUTTER FAT. 1. Milk fat, butter fat, is the fat of milk and has the Reich- ert-Meiss! number not less than twenty-four (24) and a specific gravity of not less than 0.905 (40-0. d. BUTTER. 1. Butter is the clean, non-rancid product made by gather- ing in any manner the fat of fresh or ripened milk or cream into a mass, which also contains a small portion of the other milk constituents, with or without salt, and contains not less. than eighty-two and five-tenths (82.5) per cent. of milk fat. By acts of Congress approved August 2, 1886, and May 9, 1902, butter may also contain added coloring matter. 2. Renovated butter, process butter, is the product made by melting butter and reworking, without the addition or use of chemicals or any substances except milk, cream, or salt, and contains not more than sixteen (16) per cent. of water and at least eighty-two and five-tenths (82.5) per cent. of milk fat. 256 Testing Milk and Its Products. e@. CHEESE. 1. Cheese is the sound, solid, and ripened product made from milk or cream by coagulating the casein thereof with rennet or lactic acid, with or without the addition of ripening ferments and seasoning, and contains, in the water-free substance, not less than fifty (50) per cent. of milk fat. By act of Congress, ap- proved June 6, 1896, cheese may also contain added coloring matter. 2. Skim milk cheese is the sound, solid, and ripened product, made from skim milk by coagulating the casein thereof with rennet or lactic acid, with or without the addition of ripening ferments and seasoning. 3. Goat’s milk cheese, ewe’s milk cheese, etc., are the sound, ripened products made from the milks of the animals specified, by coagulating the casein thereof with rennet or lactic acid, with or without the addition of ripening ferments and seasoning. f. ICE CREAMS. 1. Ice cream is a frozen product made from cream and sugar, with or without a natural flavoring, and contains not less than fourteen (14) per cent. of milk fat. 2. Fruit ice cream is a frozen product made from cream, sugar, and sound, clean, mature fruits, and contains not less than twelve (12) per cent. of milk fat. 3. Nut ice cream is a frozen product made from cream, sugar, and sound, non-rancid nuts, and contains not less than twelve (12) per cent. of milk fat. g. MISCELLANEOUS MILK PRODUCTS. 1. Whey is the product remaining after the removal of fat and casein from milk in the process of cheese-making. 2. Kumiss is the product made by the alcoholic fermentation of mare’s or cow’s milk. 306. STANDARDS FOR BABCOCK GLASS WARE. (Adopted by the Association of Official Agricultural Chemists of North America.) Src. 1. The unit of graduation for all Babcock glassware shall be the true cubic centimeter (.998877 gram of water at aw.) (a) With bottles, the capacity of each per cent. on the scale shall be two-tenths (0.20) cubie centimeter. (b) With pipettes and acid measures the delivery shall be the intent of the graduation and the graduation shall be read with the bottom of the meniscus in line with the mark. Src. 2. The official method for testing bottles shall be cali- bration with mercury (13.5471 grams of clean, dry mercury at 20° C., carefully weighed on analytical balances, to be equal to 5 per cent. on the Babcock scale), the bottles being previously filled to zero with mercury. Src. 3. Optional methods.—The mercury and cork, aleohol and burette, and alcohol and brass plunger methods may be employed for the rapid testing of Babcock bottles, but the accuracy of all questionable bottles shall be determined by the official method. Src. 4. The official method for testing pipettes and acid measures shall be calibration by measuring in a burette the quantity of water (at 20° C.) delivered. Sec. 5. The limits of error—(a) For Babcock bottles shall be the smallest graduation on the scale, but in no case shall it exceed five-tenths (0.50) per cent., or for skim milk bottles one- hundredth (0.01) per cent. (b) For full-quantity pipettes, it shall not exceed one-tenth (0.10) ecubie centimeter, and for fractional pipettes, five-hun- dredths (0.05) cubic centimeter. (ec) For acid measures it shall not exceed two-tenths (0.20) cubic centimeter. 17 307. SPECIFICATIONS FOR STANDARD BABCOCK GLASS WARE. (Adopted by the Official Dairy Instructors’ Association, 1911) I. Milk Test Bottle. 8% 18 gram, so-called 6-inch. Graduation: The total per cent graduation shall be 8. The graduated portion of the neck shall have a length of not less than 63.5 mm. (2% inches). The graduation shall represent whole per cent, five-tenths per cent and tenths per cent. The tenths per cent graduations shall not be less than 3 mm. in length; the five-tenths per cent graduations shall be 1 mm. longer than the tenth per cent graduations, projecting 1 mm. to the left; the whole per cent graduations shall extend one-half. way around the neck to the right and projecting 2 mm. to the left of the tenths per cent gradua- tions. Each per cent graduation shall be numbered, the number being placed on the left of the scale. The error at any point of the scale shall not exceed one-tenth per cent. Neck: The neck shall be cylindrical for at least 9 mm. below the lowest and above the highest graduation mark. The top of the neck shall be flared to a diameter of not less than 10 mm. Bulb: The capacity of the bulb up to the junction of the neck shall not be less than 45 ce. The shape of the bulb may be either cylindrical or conical, with the smallest diameter at the bottom. If cylindrical, the outside diameter shall be between 34 and 36 mm.; if conical, the outside diameter of the base shall be between 31 and 33 mm., and the maximum diameter between 35 and 37 mm. The Charge of the bottle shall be 18 grams. The Total Height of the bottle shall be between 150 and 165 mm. (5% and 6% inches). Each bottle shall bear a permanent identification number. II. Cream Test Bottles. 50% 9-gram, so-called 6-inch, and 50% 9-gram, so-called 9-inch. A. 50% 9- gram, so-called 6-inch. Graduation: The total per cent graduation shall be 50. The graduated portion of the neck shall have a length of not less than 63.5 mm. (2% inches). The graduation shall represent 5 per cent, 1 per cent and five-tenths per cent. The five-tenths per cent graduations shall be at least 3 mm. in length; the 1 per cent Specifications for Glassware. 258a graduations shall be 2 mm. longer than the five-tenths per cent graduations, projecting 2 mm. to the left; the 5 per cent gradua- tions shall extend half way around the neck to the right and pro- ject 4 mm. to the left of the five-tenths per cent graduations. Each 5 per cent graduation shall be numbered, the number being placed on the left of the scale. The error at any point of the seale shall not exceed five-tenths per cent. Neck: (Same as standard milk test bottle.) The neck shall be cylindrical for at least 9 mm. below .the lowest and above the highest graduation mark. The top of the neck shall be flared to a diameter of not less than 10 mm. Bulb: (Same as standard milk test bottle.) The capacity of the bulb up to the junction of the neck shall not be less than 45 ec. The shape of the bulb may be either cylindrical or conical, with the smallest diameter at the bottom. If cylindrical the out- side diameter shall be between 34 and 36 mm.; if conical, the outside diameter of the base shall be between 31 and 33 mm. and the maximum diameter between 35 and 37 mm. The Charge of the bottle shall be 9 grams. All bottles shall bear on top of the neck above the graduations in plainly legible characters, a mark defining the weight of the charge to be used (9 grams). The Total Height of the bottle shall be between 150 and 165 mm. (5% and 6% inches). (Same as standard milk test bottles.) Each bottle shall bear a permanent identification number. B. 50% 9-gram, so-called 9-inch. The same specifications in every detail as specified for the 50% 9-gram 6-inch cream test bottle shall apply to the 9-inch bottle, with the exception, however, that the total height of this bottle shall be between 210 and 225 mm. (814 and 8% inches). III. The Standard Babcock Pipette. Total length of pipette not. more than 330 mm. (13144 inches). Outside diameter of suction tube 6 to 8 mm. Length of suction tube 130 mm. Out- © side diameter of delivery tube, 4.5 to 5.0. mm. Length of deliv- ery tube, 100 to 120 mm. Distance of graduation mark above bulb, 30 to 60 mm. Nozzle straight. Delivery 17.6 cc. of water at 20 degrees C. in 5 to 8 seconds. In view of the fact that the skimmilk bottle can give only ap- proximate quantitative results, it should be given no consideration as a standard bottle. Table I. Composition of milk and its products. No. of Water| Fat Saeae Milk Ash Authority analyses |__| albumen sugar pr. ct. | pr. ct. pr. ct. pr. ct. | pr. ct. Tg oc 793||87.17| 3.69) 3.55 | 4.88} .71/K6nig® pee 2: sesleceee-{[87-70| 3.40] 3.50 | 4.60] .75|Fleischmann tf tt eccccecees| 6,552||87.10) 3.90} 3.204] 5.10) .70|Van Slyke ce ee jatcc peste oy 1 FOlICG: 40) 4o20 ~8.017 <0. .71|Holland® se (6 ceeeeees|200,000|/87.10] 3.90} 3.40 | 4.85} .75|Richmond Colostrum milk....... 42||74.57| 3.59) 17.644) 2.67| 1.56)/K6nig® SPORT ci vie n.c'ce wewe 43/|68.82/22.66| 3.76 | 4.23, .53) ‘‘ Cream, Cooley ....... S0S7F. 90117. GO) oo a sdcleeet .62|Holland® Skim milk (gravity). 56||90.43} .87| 3.26 | 4.74) .70/KG6nig® 354//90.52| .32) ......]. pile cligates Holland® Skim milk (centrifuge) ae be 90.30} .10) 3.55 | 5.25) .80/Van Slyke Butter milk Ritwetn oe 57||90.12} 1.09} 4.03 | 4.04] .72|/K6nig® Pease aca DLR ead! jew se ole creates «ck Holland® Whey Pee PET 46||93.38] .32 .86 | 4.79| .65|/KGnig® OR SE SRS epee 93.12) .27| .81 5.80 |Van Slyke Condensed milk, (no sugar added)... 36]|58 .99)12.42) 11.92 |14.49) 2.18)/Konig® Condensed milk, (sugar added) ...... 64|/25.61]10.35| 11.79 [50.06] 2.19] Butter, salted........| 1,676)|11.95/84.27 1.26 .58| Woll ‘¢ sweet cream.. 10||/12.93/84.53} .61 | .68] 1.25|K6nig5 ‘« sour eream... 11]}13.08/84.26} .81 | .66) 1.19) ‘‘ e unsalted ..... 242)/13.07/85.24 1.57 .12}Woll World's Fair, 1893 350/|11.57/84.70 95 .78|Farrington Cheese, SrOGIhs sss. i. 127/|36.33/40.71| 18.84 ) 1.02) 3.10|/KGnig® full cream. ar 143}|/38.00/30.25} 25.35 | 1.43) 4.97) ‘‘ ‘¢ eheddar, green|....... 36.84/33.83| 23.72 5.61 |Van Slyke ‘¢ eheddar, cured 27||34.38/32.71| 26.38 | 2.95] 3.58|/Drew ‘¢ ~— World’s Fair Mam’th, 1893 1)/32.06|34.43) 28.00 5.51 Shutt “s half-skim .... 21)|39.79|23.92|} 29.67 | 1.79] 4.73)Konig® bi ahs ee eee ae 41/|46.00/11.65) 34.06 | 3.42) 4.87] ‘‘ ‘¢ centrifugal skim..|....... Fe Wl age MP 2 in a ge 5.2 |Storch APPENDIX. 1 ,70 per cent. albumen. 4 13.60 per cent. albumen. ; Mostly European samples. 6 Massachusetts’ samples. 2 Forty-two analyses. 3 Hight analyses. and Its Products. a y Testing Malk 260 "qej “40 Lod 0Z “yey ‘yo tod € 4S aT q4@ SUTYSo} H[TUL WOI yy "JBJ OC, OJ *[OS [8IO} “O° CF s “qBJ Od, 0} “TOS 1810} ‘0° OG "YBJ oq OF *[OS [eI0O} *O'd cE “MILUL WITS TUOTZ SUID S| "‘qe4 “Yo Jod GT ‘WaTyS J[VH 4b aASaaHy | |} | | /syonpoid Airep Joy} spiepuerjs AVID pueB 9}¥}S "19 Lad | qey jou SPILOS GIT = |-~7eung pue dey SL ee enTR eae = cain Bei raat (@) oi eee a te zylOX MON (a WR fink igs as = Aosiof MON Cie se a ee oe artysdueyT MON a EN Sr eae Wixtehamentche pre ae 000° 1 0,7 eT aa ai aera eB} OSOUUT I €€-660 "I "I5 “dg QSL ao Gaater e* See emenS UBSITOTIN al Resi ysnsny-[lady eT IPicerntela a; S}JOSNIVssB IL ar leachate sie ouleN eae froetey nr cere ree Tae aS a CAT | Dt A i he al pe ois Paka BMOT [oer] ar Ate BI81004) | [ozr] (--erqumoo FO JOIIYSICL eet Ae Lanne <2 OM SOTOG) --------- -------=---err0f1729 *70 dad Sprtos TROL, MII | | (Gera ents |p eneaere ce Kista kamen coe | € | Wega | i Se tel tte || 02 ero bias | WeA@aer Otten ee | | 1d ds || | 1 5 | | S | 66 Lise ate 08 || 82 | || SO$ Mame cd G poe ee || € | i | oe a) Wels cea COU mH | | 10 19VVM | | | POLO 21 malt || || IOAO JON || 1 | g8 Wea pear Sa etl ae Lise veg | 10 lag || 40 dag 1 40 log | We || — = qe I isto | qea — | | = z | } 1 | MTIM | UaALLoAg WVaUD | “WIS | | | TL eI98&L Appendix. JO 4u900 Jed ZT JO JUaTeamMbe eq} AyUeNb ut oq [[eUS ‘eIn{[NopIsy Jo ydoeq ‘syonpoid Aiyep 1OJ sprepuBys FuUIqWoseid SMe] OU BABY POUUBU 4JoU sazEID VBJ OF [1BY8 “yUeo Jed cz SpI[os YOIYA Jo ‘H[]UI epnsd UL Spl[os HL ;UX Y[TUL posuepuood Jo spl[Os H[fUr oy} O[YO puw YIOX MIN ug ‘S'O ‘Arjsnupul [euljuy “ing ‘ez “o1IM WOU sprepuRys eMBIST —eeee ll —e—ElleeEllEEEEEEESESEE™E™ED”™ESS_eeeeee ee ’ mT yOr 8 DIOIS*P WITS “"VBj°9 °C QT P.wayyS JIVH yey (0 'd og ‘mM BeID TFUYI| °°: ‘qey od g MOTE ‘p,TAT AS yBy YO tod g ‘urvero GyINOJ-euO : “yBJ yO ied gj ‘urvero J7ey-0u0 BJ 40 10d ¥z ‘ULBVAID SYJINOJ-We1g ], 78} “40 ted 7g ‘urwerd [[ny “IOV BM \ 40 10d FT IOAO JON es es er c’s LG O'F O¢ "od 7 SPTLOS ; OGL eer eeeeeeree 8 “65 Sabeasian¥.cy a Secweaaes ee QOL [rc 0°$ 6 ater vestue|| stccccesres = ¢ € sls See ree joa 4q wWIBa10 "40 1ed 9 paaecwhs saat Ra ‘o'd gy g "Toa £q umIsel9 Sp Is 9) wis [6] CSI (oUlog ) puv[.ezIMg Sedg |(4 nqurexq) uvurteg "ST sess STE I] aouRl yy [¢° tt] eeccecccececeoe (sjsAyTRuw ‘qng ‘009) puslsouq 19 a eal pag BINOFT Sk gs 0°<1 wIqdjepeiygd 4, rer a ayeug | nore okt pie “roateq 7, 0'°Z1 "°"OSBOIGD 7 see +-s0e0es TONSOE 0'SI “"“QIOUITY[B_ JO At ee sreseseeleeseeeses sett” THISTIOOBSTAL, [tr] eeccccscoece UOVSUTYSBAA CA “oun pus Av] "see"**-BTTTOIBD YING ZI eee eeceenee puss] epo"ony (Css8[9 pe Puy pg 291719) C21 eeeresees *eraea[Asuueg ‘ ZI eae re nen ost eS 262 Testing Milk and Its Products. Table I. Quevenne lactometer degrees corresponding to N. Y. Board of Health degrees. (See par.114) | Bd. of Health| Quevenne ||Bd. of Health} Quevenne ||Bd. of Health| Quevenne degrees. scale. degrees. scale. degrees. scale, 17.4 81 23.5 101 29.3 17.7 82 23.8 102 29.6 18.0 83 24.1 103 29.9 18.3 84 24.4 104 80.2 18.6 85 24.6 105 30.5 18.8 86 24.9 106 30.7 19.1 87 25.2 107 31.0 19.4 88 25.5 108 31.3 19.7 89 25.8 109 31.6 20.0 90 26.1 110 31.9 20.3 91 26.4 111 82.2 20.6 92 26.7 112 32.5 20.9 93 27.0 113 82.8 21.2 94 27.3 114 83.1 21.5 95 27.6 115 83.4 by f 96 27.8 116 - 33.6 22.0 97 28.1 i7 33.9 22.3 98 28.4 118 84.2 22.6 99 28.7 119 34.5 se 100 29.0 120 84.8 3.2 Sp. gr. (8)= | 0.0000) 0.0001] 0.0002) 0.0003) 0.0004) 0.0005} 0.0006; 0.0007/ 0.0008) 0.0005 1.019 1.020 1.021 1.022 1.023 1.024 1.025 1.026 1.027 1.028 1.029 1.030 1.031 1.032 1.033 1.034 1.035 1.036 (See directions for use, par. 125) Appendiz. 5 268 Table Y. Correction-table for specific gravity of milk. La] oe) Temperature of milk (in degrees Fahrenheit). g.5 FL 51 52 53 o+ 59 56 57 | 58 o9 | 60 20 | 19.3| 19.4] 19.4] 19.5/19.6/]19.7]19.8/19.9/19.9] 20.u Tint eA. G1 B0.o } 20.4 1) 20-5 | 20,61 20.71 20:8 | 20-9 | 20:91 21.0 St leo) ol o|, ol. 41 20-5 2b. 6 2 FH B18 | 21 9 |.21.91 22.0 mi le2o.e |-os.0 | 22-4 22°65 | 22-6122, 7 1 22-8) 92-8) 22/9.) 93:0 OE 2s. | wale | 2o.41 23.5 123-6) 23.61 23.7) 23.8 | 23294 24.0 25 | 24.2| 24.3| 24.4] 24.5 | 24.6] 24.6 | 24.7] 24.8] 24.9] 25.0 26 | 25.2) 25.2) 25.3] 25.4 | 25.5 | 25.6 | 25.7] 25.8) 25.9] 26.0 27 | 26.2] 26.2] 26.3) 26.4 | 26.5 | 26.6] 26.7 | 26.8 | 26.9] 27.0 Be atl boat oe eh ood, QE Pat.) 27.6 | 27.71 27:81:27 291 28.0 29] 28.1| 28.2) 28.3] 28.4 | 28.5] 28.6] 28.7 | 28.8] 28.9] 29.0 30 | 29.1] 29.1 | 29.2] 29.3 | 29.4| 29.6] 29.7] 29.8|29.9] 30.0 31 | 30.0] 30.1 | 30.2) 30.3 | 30.4] 30.5] 30.6 /30.8/ 30.9] 31.0 oe | op.0) 31.1) 31.2 ).81.3) 31.4) 31.5 |81.6)31,7139r.9| 32.0 oo |) o1.9}| 82.0) 82.1) 82.3 | 32.4) 32.5 | 32.6] 32.7) 32.9) 33.0 34.| 32.9 | 33.0} 33.1] 83.2 | 33.38 | 33.5 | 33.6] 33.7 | 33.9] 34.0 35 | 33.8| 33.9| 34.0] 34.2 | 34.3 | 34.5] 34.6 | 34.7 | 34.9] 35.0 a ff | Lf | | Nf —_— | | FE S| | |_| MR | 20 | 20.1} 20.2} 20.2} 20.3 | 20.4 | 20.5 | 20.6 | 20.7] 20.9] 21.0 21 | 21.1} 21.2) 21.3] 21.4 | 21.5) 21.6] 21.7) 21.8} 22.0) 22.1 22 | 22.1} 22.2| 22.3] 22.4 | 22.5] 22.6 | 22.7 | 22.8/ 23.0} 23.1 23 | 23.1] 23.2] 23.3] 23.4 | 23.5 | 23.6 | 23.7 | 23.8) 24.0] 24.1 24 | 24.1] 24.2] 24.3] 24.4 | 24.5 | 24.6 | 24.7) 24.9] 25.0] 25.1 25 | 25.1] 25.2] 25.3] 25.4 | 25.5 | 25.6 | 25.7} 25.9] 26.0] 26.1 26 | 26.1]. 26.2) 26.3] 26.5 | 26.6 | 26.7 | 26.8 | 27.0) 27.1] 27.2 27 | 27.1) 27.3) 27.4] 27.5 | 27.6 | 27.7 | 27.8 | 28.0] 28.1] 28.2 28 | 28.1] 28.3] 28.4| 28.5 | 28.6 | 28.7 | 28.8 | 29.0) 29.1] 29.2 29°} 29.1] 29.3| 29.4] 29.5 | 29.6} 29.7 | 29.9| 30.1/30.2| 30.3 30 | 30.1] 30.3) 30.4] 30.5 | 30.7 | 30.8 | 30.9 | 31.1] 31.2] 31.3 31 | 31.2] 31.3} 31.4] 31.5 | 31.7] 31.8] 31.9 | 32.1 | 32.2] 32.4 32 | 82.2| 32.3) 32.5) 32.6 | 32.7 | 32.9 | 33.0 | 33.2 | 33.3] 33.4 33 | 83.2] 33.3] 33.5] 33.6 | 33.8 | 33.9 | 34.0 | 34.2 | 34.3] 34.5 34 | 34.2] 34.3] 34.5] 34.6 | 34.8 | 34.9 | 35.0| 35.2) 35.3] 35.5 35 | 30.2} 35.3] 35.5 | 35.6 | 35.8 | 85.9 | 36.1 | 36.2| 36.4] 36.5 DIRECTIONS.— Bring the temperature of the milk to within 10° of 60° F. Take the reading of the lactometer and that of the temperature of the milk; find the former in the first vertical column of the table and the latter in the first horizontal row of figures; the figure where the horizontal- and vertical columns meet is the corrected lactometer reading; e.g., ob- served, 31.0 at 67° F.; corrected reading, 31.9 264 Testing Milk and Its Products. solids not fat, corresponding to 0 to of Table Vi. Per cent. 6 per cent. of fat, and lactometer readings of 26 to 36. (See directions for use, par. 120) “yey JO ‘4U00 Jog 36 2 | 83 | 34 |} 35 LACTOMETER READINGS AT 60° F. 28 | 29 | 30 | 31} 3 | — Seseere NANNNN Vex) > hk rk Fe Fk I~ Xe | le Sl Sal Sl ~ yk be Sl lt ll | dt ll ell el td 1D I= OS es 10 P= Oo rs oO 1D P= So es oD LOT Deed i9 Os r= So ri OH CO OH CH SO OH OH CH CO 6 f= r= ~~ Xr | Sel acl ll Sell Sol | dl Sell ell el aed SONHOO ONMHOOD ONMSDHD ONHNDD OCONHODW oe St Se a sar as ia een aa ak Fa oro De cir ais Sng a eco ogee yt des a “Vey COMA OH iO © = CO Od OrN o <= iD © r= LH Ora oo <= OO OG oooco oooco Se ee Me Boe oe Set ee Sst et NANNAN NAAN A mn oD So et oO 1D I> So rs ~y-~OO ie offe ole oio> o>) Ceo Neh ew ee lor Ror or kama) Oye. fer pe a, ooonrr fe. or ve Pb ie men Se Se eee oD OD CFD CO 0 OO DO OOOO (coc oe oor Ker) lor Ror kor koreer) C2 BD G2 Oo > > > SO? S? S OS Ast co Oo ONAtHSO OO enh as Nelle —elveiie) |e St oe Se fo ooo olfe e) OS AIH co OO LD UD LD LD LD eth se, cea ve LQ I= S24 oD NAAN OD oD an = Ee Xe 0) oo°o°o°o LD P= Oo rst OD OD 6 CO ie, 0 ecto, Me % G9 Go 6 o ri oO) 1 =~ Oo Oe So Od S2 SD Org) 6) at Die ie OOON xi SATS LD P= D2 1 oO 1D I= SD et oO 19 Iy OMe oO LD I= SD rs oD 1D I~ OD I~ iy & OD eee ONHSO Onto eO SAIS SO oO SOE Sieaien c CO oO UD LD LO LD uD I A 85 lo offe oie oor Wor) We Be iie ioe) LD i> D4 oD oD 6 CO oo°o°o et Siete 0 eee eof S8SS5s5 4ue0 Jeg Reet sacka CO OD ODED CD HHA HH ioinininis winnion © ~ mWtSDS AHSHS HORAN HHROM ODOM wOoRS = = © OOOO rr I~ i- Ii- ~@ & 0 6 SO oS PPADS ooocr Sie ae N BS oe) PRHABAAD MPBARWIAP® ABWWAD ARMRHO SOSSSO SoocSo oo = See | Se ee BR cee ee | ee ee ee re m= :S ODA Asis FPONHS DONHD DONDVO DOAto = 19 OTN Mis WHOSS SREKR RHDHHD BHSAHS cS S BARA BPRARWRW®2 BWBWBAWD ABABA AaAaBaa asoaaa cs ‘ SONOS NHOHS NHoOD OS AYTOOnN Mnr-ame ow ca Rs x RaKgn pe AAA A 60 9 60 33 VISRS Diginigs SSoOSr 2 2 DPAARABARA BARWBWRPP BRWRWA BRMRBHRD Anaaa aacaaca a SCHONY SCHONYH OOHMD rome rouMo © © oo z 23 | ® AAR SRSSS SConns SAA AN 09 69 o8 SRVAY H S at WHO DH DNABMD? BABWAW® VWRMAGBHD AQaaaa aaanaa «a o SOIOgrD HAMID O Mone I+ 0 A+FtoDO ~Oore - ba 7, n | SS86s RFEERR DODOs RALZS SOOGGm Soa: ree ‘3 ~~ A WAND NWO DWMOWNDOH DNNWDH DHNHNWND BaAaa sascoaa «o _ < CO OO CNSONH DHONH BDDOONDS OO ronmto = S a peutepebbe HHHIND HGHSSS SSRKNS KreOee HoBaae & 3, ® oe WD 2 HO DN WODOOH DNWDNHH DHDHNOH HDHDHHD KDHoKnDwDO o = on) OMWMr~ OD aso rS> MOLE D BNO D RAMDrO sH cS ~ C|/2| 8 | SSSR ANAARR BSR5R GHEE BBBES SSSBR RK ae oe 5 WA DDNW WDMOWNWOH WDNWHMDH WDHHHNH HDOHDDHD HDHoDHDDO Oo IDr-aNY DHSAH BDHONtT ODO ODOH Oe = S|] a | 25282 2688S SE2tt SARAN SALAS SBqR9 4 Q C Nh HY DDD WDMDHMHDH WHDHDNDH DODD H HDowODW oo te SANTOR AMOR D VWHOEHR HAOMOrO HHDRO MoODh S/F] a | 8888S EXGKR RARER SRRER SSSSS ASSER Q a fis SS IS SS i ie oS is ie is he he WOM DOO ADNMNMOMD WwW IDs DHOND oODoON CSOHONH DOON We} a 5 Ba, Pots bs be eo ie fe i ee es i he bs ie pe pee Be eee o ONHOO ONANSO Sclstc Clr D> mFOIOrOD BAMDKES = 2 eames AANAAN & 69 09 03 38 FRB IDnidisisnh Sessoe RF ico} __ “4yvj JO ‘ued Jog SPEDE ODED ODED AD EDOD HHH Hew wisi wow © 266: ~ Testing Milk and Its Products. Directions for Use of Tables VIl, Vill, IX, and X). TABLES Vil, and Vill. Find the test of the milk in table VII or of cream in table VIII; the first or last horizontal row of fig- ures, the amounts of fat in ten thousand, thousands, hundreds, tens, and units of pounds of milk are then given in this verti- ecalcolumn. By adding the corresponding figures for any given quantity of milk or of cream, the total quantity of butter fat contained therein is obtained. ; Example: How many ponds of fat is contained in 8925 lbs. of milk testing 3.65 per cent.? On p 264, second column the test 3.65 is oe. and - by going downward in this cu.uinn we have: SOOO! WS: - occtecsceccecsocseccssses 292. Ibs. QOOMIDS eee reenedcdeleeses 82.9 lbs. QONIDS Hivetceckscus eeeeceke sees -7 lbs ip) Ney Weare cocoa ae 2 lbs 8925 lbs. of milk. 325.8 lbs. of fat. 8925 lbs. of milk testing 3.65 per cent., therefore, contains 325.8 Ibs. of butter fat. TABLE IX. The price per pound is given in he outside vertical columns, and the weight of butter fat in the upper and lower horizontal row of figures. The corresponding tens of pounds are found by moving the decimal point one place to the left, the units, by moving it two, and the tenths of a pound, by moving it three places to the left. The use of the table is, otherwise, as explained above. Example: How much money is due for 325.8 lbs. of butter fat at 1544 cents per pound? In the horizontal row of figures beginning with 15} on p. 247, we find: 20 lbs 3.10 5 lbs ‘77 8 lbs AZ 325.8 Ibs. $50.49 825.8 Ibs. of butter fat at 1544 cents per pound, therefore, is worth $50.49. TABLE XI. Find the test of milk in the upper or lower hori- zontal row of figures. The amounts of butter likely to be made from ten thousand, thousands, hundreds, tens, and units of pounds of milk are then yiven in this vertical column. The use of the table is, otherwise, as explained above in case of table VII. Example: How much butter will 5845 lbs. of milk testing 3.8 per cent. be apt to make under good creamery conditions? In the column headed 3.8, we find: BOOO MIDS ise cteceserccthew scorers 209.0 lbs SOO MSs see castens oeececones 33.4 Ibs. AQMD Sse etccetencescdsoaccrese 1.7 lbs 5 lbs .2 lbs 5845 lbs. 244.3 lbs. 5845 lbs. of milk testing 3.8 per cent. of fat will make about Sic 8 lbs. of butter, under conditions similar to those explained in par. 220. Appendia. 267 mt bo CO OUD “100 © Table Vil. Pounds of fat in | to [0,000 Ibs. of miik. testing 3.0 to 5.35 percent. (See directions for use, p. 266 ) ; E 3.00/3.05/3.10/3.15)3 . 20/3 . 25}/3 .30|3 .35/3 .40)3 .45)3 50/3 55 g Milk Milk Ibs. Ibs. 10,000} 300} 305} 310} 315} 320) 325}| 330) 335) 340) 345] 350) 355)/10,000 9,000|| 270) 275) 279] 284] 289} 293]) 297} 302) 306) 311) 315) 320 9,000 8,000|| 240} 244) 248] 252] 256] 260} 264! 268) 272) 276) 280) 284)| 8,000 7,000|} 210} 214) 217) 221) 224) 228} 231) 235} 2388) 242) 245| 249 7,000 6,000]} 180} 183} 186) 189) 192] 195]; 198) 201} 204| 207) 210) 213)) 6,000 5,000]|. 150} 153} 155} 158} 169) 163}| 165) 168) 170) 173] 175) 178)| 5,000 4,000]| 120} 122} 124! 126} 128} 130]] 1382) 134] 136] 138] 140, 142]) 4,000 3,000]|90.0!91.5]/93.0/94.5)96.0/97.5}/99.0) 101) 102) 104) 105) 107]| 3,000 2,000 60. 0/61. 0/62 .0/63 .0}64.0/65 .0}/66.0)57 .0/68.0/69.0/70.0/71.0)| 2,000 1,000 30 .0/30 .5/31.0/381. 5/82. 0/32 .5)/33 . 0/33 5/34. 0/34 .5/35. 0/35 .5}] 1,000 900}|27 .0|27 .5}27 .9)28 .4|28 .8/29.3 29 .7/30.2/30.6181.1/31.5/32.0]] 900 800]}24 0/24. 4/24 8/25 2/25 . 7/26 .0/26 4/26. 8/27. 2127 .6/28.0/28.4)) 800 700}|21 .0}21 . 4/21 . 7/22. 1)22 4/22 .8}/23.1/23 5/23 .8}24 .2/24.5)24.9]| 700 600}/18 .0/18 .3)18 .6/18 .9]19 . 2/19 .5}/19 .8/20.1/20.4/20.7)/21.0/21.3]| 600 500}|15.0)15.3]15 .5)15.8]15.0/16.3)/16.5]16.8)17.0)17.3)17.5/17.8)| 500 400}|12 .0/12 . 2/12. 4/12 .6]12 8/13 .0}/13. 2/13. 4/13 .6)13.8)14.0)14.2)| 400 300} 9.0) 9.2] 9.3] 9.5} 9.6) 9.8!) 9.9/10.1/10.2/10.4)10.5)10.7|; 300 200} 6.0) 6.1] 6.2) 6.3] 6.4) 6.5)| 6.6] 6.7] 6.8) 6.9) 7.0) 7.1]| 200 100|} 3.0} 3.1} 3.1) 3.2) 3.2) 3.3]) 3.3) 3.4) 3.4) 3.5) 3.5) 3.6)/ 100 90)| 2.7; 2.8} 2.8} 2.8} 2.9) 2.9] 3.0] 3.0} 3.1) 3.1) 3.2) 3.2 90 80]| 2.4) 2.4] 2.5] 2.5} 2.6] 2.6!) 2.6) 2.7] 2.7) 2.8) 2.8) 2.8 80 70|| 2.1) 2.1] 2.2) 2.2) 2.2) 2.3)]| 2.3) 2.3] 2.4) 2.4) 2.5) 2.5 70 60]| 1.8} 1.8] 1.9} 1.9] 1.9] 2.0}) 2.0) 2.0) 2.0) 2.1) 2.1) 2.1 60 Sido) Po) 6) sk 6) 1.6) £6 1.7) 1.7) 1.7) 2718) 1.8 50 40]) 1.2) 1.2) 1.2) 1.3) 1.3) 1.3]) 1.3) 1.3) 1.4) 1.4) 1.4) 1.4 40) ao ote cork vot Se OP LO 10) LOK EOP EO) Ta: Td 30 ieee LO cel) Onan oc Steal GAL EP Ud ak 20 es =| leer: Ses | es‘ Eee; | ees || ier | Beers ee ee | | 10 Dita 2s oy SO) oats OH: sop SSL AOL eo) SBE alee cat cel aa Oil | 281 aL, eo, xOl” OP 4) Sn Sit) ER S| | a ele ae Ne ee eet” ee RO Se. Ob Ry, ae. | a a ey A a 7h eg Mele MR GRP Re, ROS. | CER Fe Sal Ce a oS 9 agen Ree 7 mei "PR ewe gan Urals | Meal | Se Mb cs 0 eek eosin wknd) AS ods See Es ay od : SV Tyra Pes Ul ead 5 fizaets 8 janie | kcodeee Neen © ibaa 4 ieee Oe © bea 3 s 3.00|3 .05)3. 10/3. 15)3 . 20/3. 25]/3 . 30/3 .35)3 . 40/8 .45)3 .50|3 .55 g _— —_——___ } J | EE | CE ff | | Sh | ee | 268 Testing Milk and Its Products. Table Vil. Pounds of fat in | to 10,000 Ibs. of milk (Continued). 8 3.60/3.65/38. 70/3. 75)3 . 80)3 . 85]/3 . 90/3. 95/4 .00/4. 05/4. 10/4. 15 o a | Milk Milk Ibs. Ibs. 10, 000|| 860) 3865) 370) 375) 380) 385 410} 415}/10, 000 9, 000|} 824) 329) 333] 338) 342) 3847 369} 374!) 9,000 8,000)| 288) 292} 296} 300} 304} 3808 328} 3321] 8,000 7.000)} 252} 256} 259} 263} 266/°270 287| 291)| 7,000 6,000|| 216) 219} 222) 225) 228) 231 246] 249|| 6,000 5, 000)| 180} 183} 185} 188} 190) 193 205} 208/| 5,000 4,000), 144) 146} 148) 150) 152) 154 164} 166!) 4,000 3, 000|| 108} 110) 111) 113) 114) 116 123} 125}| 3,000 2,000 72.0|73.0/74. 0/75 .0|76.0|77 .0||78 0/79 .0|80. 0/81. 0/82 .0/83.0}) 2,000 1, 000/136 . 0/36 . 5/37 . 0/37 .5/38 .0/38 . 5|/89.0/39.5)40 . 0/40 .5/41.0/41.5}| 1,000 900|/32.4!32 .9|33.3183 .8/34. 2134. 7|/35.. 1/35 . 6/36 0/36 .5/36.9)/87.4)| 900 8001]28 . 8129. 2/29 .6/30.0/30. 4/30 .8}/31. 2/31. 6/382.0)32.4)382 .8/33.2/| 800 700]|25 . 2125 . 6/25. 926 3/26 . 6/27 .0)/27 3/27. 7/28.0/28.4)28.7/29.1)| 700 600]|21.. 6]21 . 9/22. 2/22 5/22 .8/23.11)23.4/23 . 7/24. 0/24.3/24.6/24.9]| 600 50018. 0/18 .3]18 5/18. 8/19. 0/19 .3})/19.5)19.8/20.0/20.3)20.5/20.8) 500 400/|14.4}14. 6/14. 8/15 .0/15.2|15 .4|/15 6/15 .8)16.0/16.2/16.4)16.6}} 400 300|}10.8}11.0/11.1/11..3)11 .4/11.6)/11.7/11.9)12.0)12.2)12.5)12.5)| 300 2001] 7.2] 7.3] 7.4] 7.5] 7.6) 7.7]! 7.8) 7.9) 8.0) 8.1} 8.2) 8.3)) 200 100|| 3.6} 3.7| 3.7] 8.8] 3.8] 3.9)| 3.9) 4.0} 4.0) 4.1) 4.1) 4.2)/ 100 90|| 3.2} 3.3) 8.3) 8.4) 3.4) 3.5]] 3.5] 3.6] 3.6) 3.7) 3.7) 3.7 90 80/| 2.9] 2.9) 3.0) 3.0) 3.0) 8.1]] 3.1) 3.2) 3.2) 3.2) 3.3) 3.3 80 70|| 2.5| 2.6) 2.6] 2.6) 2.7| 2.7|| 2.7) 2.8) 2.8) 2.8) 2,9) 2.9 70 60]} 2.2] 2.2) 2.2! 2.8) 2.3) 2.3] 2.3) 2.4) 2.4) 2.4) 2.5) 2.5 60 50|} 1.8] 1.8] 1.9} 1.9} 1.9] 1.9]] 2.0) 2.0) 2.0) 2.0) 2.1) 2.1 50 40] 1.4) 1.5) 1.5) 1.5} 1.5) 1.5)| 1.6) 1.6) 1.6) 1.6) 1.6) 1.7 40 80}) 1.1) 1.1) 1.1) 1.1) 1.1).1.2]] 1.2) 1.2) W2)1-2) 22) te 30 201 oF Tee Th 8) Bh Re 28S Be) ire nee ater 20 10}} .4| .4| .41 .4) .41 .4)) .4) 4) .4) 24 4 10 Oil Sb oaBh Bl a Bl Bh well kine eh ena eee a deren 9 Sh. 8l +8) Spo eer aol OL aN Ol con eee ees 8 To 3)) 8p oS 8ly eal Ol Secollecsd|: S20) col) ORI OWOrRO mem hohe cm BOWIE NORD WRPODONW PD, Ke bh we bm NOR OWOWAID WWORDWOANWS eee eee lemme wel eee weet eee eee tee wel eee eee lisse wee le seeee eee eerissaseriseseselsseees 4, 20/4. 25/4.30|4.35)/4. 40/4. 45)/4.50/4.55/4.60)4.65)/4. 70/4. 75 2,000 1,000 bo CO & 01 > ~1 00 © “4saL 270 Testing Milk and Its Products. Table Vil. Pounds of fat in | to 10,000 Ibs. of milk ( Continued). E 4.80/4.85/4.90)4.95)5 .0015.05//5. 10/5. 15/5. 20/5. 25/5 .30|5 .35 2) , 000)/96 . 0/97 .0)98 .0/99.0 ic 0001/48 . 0/48 .5/49.0)49 .5/50.0/50 .5)/51. als. 5/52. 0/52 .5/53 .0/53..5 900}/43. 2)43 . 800))38.. 4/38. ket Ft DO BO CO CO rt re bo bo bo GO CO PopoOSereop mI WORI MOMOMOROR WODNRDURWIE hob eo Rte bobo Coto RR OTC RO RO HR OO ht et rE DD AD CD CO POSS HOE ehh mh MOMOMOMNON ODODONDDUYND HHO MOMOROROR ONORWHODN bt BS OS He OTS 1 © eecerefeceeec|sccseveleoscsee kN for) Se ae (=) 7 On on REPRE HKw..s MDW RR WOUSMSUSA MEOH CO OIRO MNOMODHOHA HwRhOONH Sethe pe PRO ROCCO RON MOM AH AHa NwwmMnnoenmns Rt et BD BRD CO CO pS fe Bebo wwO PRR GO US Or or oS HE DNR RO NODHRSHONWN WRAWDOW ARO et bo ho 0 ree bDpmwwarhre COO Garena er DoDDGo CD PRON TH AeEDWNNDN Wewnowmmow Sep ow mt Re NWWOWO RR CONSE ANA Me bob oe HH Ww PRO CHOSEN NN0O WoonNonwnepya Seb GW rR COLO OLS OLS OO HH bDDwWwWRRA MOMoMoNonN SOSSOSSSO Sh bh 0 OD MOD WORN NMOMNSOMNSOMON Heb we RR 106 ee | ef | | Le | | P| J | — | ——————_ 3 8 4.80/4.85)/4.90)4.95)5.00/5 .05//5. 10/5. 15/5. 20/5. 25/5. 30/5 .35 ket e bo bo CD GO De OReNDNWO RAR Or O10 hb int bet KO OD SDH OH 8 a 9; 000 2,000 1,000 900 800 700 bet DD CD HR OVS I CO. it 9 Appendiz. Pounds of fat in | to 1000 Ibs. of cream testing Table Vill. 12.0 to 50.0 per cent. fat. (See directions for use, p. 266 ) ooo oo So S =2S383R8 O' 18, VO, 16) 6, ah 2 0ase UM ere & | Se ee Gua Cae ted Pe NO N10 O co mi ON OO <1 Sr CO SD mein win co re =e O29 tel eh Oe. a.” Ree © oD TReeeZR a | AAAS SRShwmesN Sogeue N Ve) On APTOOON WO ive) on co a | RANSEERPOS Wigsedeed Gees ie aS a ae Se ma wei ee oe ee oe RRaSSASeOR cadadad Vea ea 1 anaes rN eS RS Rt et TONOS fo) oS a | RaRSaRcesa GSosssrsa SS RBRSR CA Nate et AN St ee In S 1S t a | RARESAS denadsrad TSSSXSkse . Se ON et et et ON ON 0 = WONOMOONOOH ONO a | LHSSTRSESA JaSSanemwa ee AK eA i i) ot rt OIL NS XT rROMN DOC ite mn co | | HSVSRrassey eae SHSRIASTS ee | ASS ete DWOmNS N BDOmMAAIOOOWN a | ASESESSSSA Segscasen SHAR TeSA SRBOEOCOKMAR ADR ONO WHA PB O1d HON -- ) | RSSERSeBsa Sowa swdwel BEUASISTS B32 SR SeSsseesse S) & | S2SSRS2SSR COMNOWOWA BSS FRSSSIR Sees et Rd ee ed et =n Trio Or oa me N OHIO Or Oo Bie ad a ao a: See eer ee denidet Sanne eet et tee ON tO N [To] N ie *] a. | REIAESESSA Sincatcad Send (=. WOON Cee All Sd MOANDOH TE Lr Ke | Rega SeSear Gaiededad Saat o=n No ol-> =) MON OOMONS a SAG ASESIGA. cae at a ee owcscw iS | Bexsas maNoOonotars Dee es Pat ae 5 anee ae ee wee ed CoON oS CNOMOONODM Ns i) ~~ oa FRASSE Bi cieis ett ee or — 00 for) oO By He OLa NO | 1 00 a oO | | SISSRSBsas HSSrssod neaneQaas Pa S HSTASHOTA N i=) won| at ESESEGEGRE SSPSESaRS 18 Testing Milk and Its Products. 212 Pounds of fat in | to 1000 bs. of cream (continued). Table VIfl. . SeSRS Ree SS ccc ca SSBSSSSSR iw 1 S “eangncenes saa eaenea CREB LEDS Tt z pot ads Seiabeaieh ade FS Ps cepa bell ot Ey on ONS nN * 63 Fa aes = Fo. eaten eT es eS) ea x BS SStES @ | VSSENNSS” SSRRASIAY Noemie SMODAADAHR MoCaANDOOIWR © aytrt = | SSRSRAEES™ Sicasasss HRIAEESEE WONOSMONS MONOGOSTENO TMONSOo =) Je) SrYBSa Cocoa < 8© © © « s «© «@ Los SNR SOBSS i | SSAA AA SSanncee* ig 3 Ce mit nso Doe al eo & @ | WISER TA SSERRSRe* Geeeaa [ony as) MN Py G6 Wh) Se er ers al Ps 8) 8, ° on roe 00 = | VSGGNNGA SESSNEROX adden” =| SSaSRASN cece dea tee SRA med eee ed SABANmA 6905 COI DWOMNIDOWOAN OOMNOCWDOWN OOmNODOMHN Q Gk {= Bo via ale Sieh Saphisl ae oe RSESBSASAOS S| SESRASERP* Coagasdes Bocdeace cove eos OD eM eg Nie ute ah At his yey Keun 8248 ST -) 2H = | WABAGA Win USAR SSNS Coane S SEASLSSRES COCCSSSSS SRESSSRES = SSEASARS 7 ENRARSEe cucee wet CN 6) SHLD CO P= CO SD PN 60 HOO I OO wot (XIV OD =r 10 SO Pe OO SD = ERaRASSAES Giagecore Gataende. Asc OO HO NAHOODMONMOCO CC! Ts B=) z BSa8ASRS°8 Uoggedens cosacca Z AAA a bet beep oO BONNN Sms MON OTH Ot lt tt tl tll 2 Sa cceesene Toco lets aaeeeters as) Be ANS NOM nOWONG %j« + « © + ee @ OAAN Sa OANA AA Ye) iB Bee See ee eee BBSSESERR is & BAAN oa MOANA z | SSRRSEESSS Sieceacee Sheseaees SRRacss MANNA SRAM DONROR RTAONNROH tO re) ar BRR QS om Os BOSSA Sos osces RERRSH SER eed AANA = a | S@RSESHS=S gowscaise #a5cekeea Fes Bea NN cae NAN Se SPERSID SY AOKROHTHAG Pores aoc = SRS OsBNeSSe Se ESLSBASS gue | pebriaead tan Hane che!) cane “3 sss $85 S S SSS SOROOHHHAIs woL| dl, SSZSSSSSRS SSESESES Appendiz. 273 Table IX. Amount due for butter fat, in dollars and cents, at {2 to 25 cents per pound. (See directions for use, page £(€.) Tr Pounds of butter fat. Price pound, cents. 1,000; 900 | 800 | 700 | 600 | 500 | 400 | 300 200 | 100 *sjue0 ‘punod izod e0}.1g —)} | —————__ |__| | SS CTS LN | | | LTT eS Le 12 |/120.00}108 .00} 96.00) 84.00) 72.00/60.00/48 .00)36.00)/24 .00/12.00|/12 12}}/122.50)110.25} 98.00) 85.75) 73.50)61.25/49 .00/36 .75)24 50/12. 25}/124 12$}/125.00)112.50 100.00) 87.50} 75.00)62.50/50.00/37 .50)25 .00)12.50)/124 _ 123||127.50)114.75/102.00) 89.25) 76.50/63.75/51 .00)38 . 25/25 .50)12. 75)|129 13 |}130.00)117.00)104.00) 91.00) 78.00/65 .00/52.00/39 .00/26. 00/13 .00//13 13}||132.50)119 . 25/106 .00) 92.75} 79.50)66 .25|53 .00)39 .75)26 .50)13 . 25))/13} 133}|135 .00/121.50)108 .00; 94.50) 81.00/67.50)54.00)40.50/27 .00)13.50/|134 13}/|137.50)123.75)110.00| 96.25) 82.50/68. 75/55.00)41 . 25/27 .50/13. 75)|133 14 ||140.00/126.00)112.00} 98.00) 84.00/70 .00\56 .00/42.00)28 .00)14 .00)|14 144/|142 50/128 .25)114.00} 99.75) 85.50/71. 25/57. 00/42. 75/28 .50)14. 25//144 143}|145.00)130.50)116 .00)101.50) 87.00)72.50)58 .00/43 .60/29 .00/14.50))143 143)|147 .50/132. 75/118 .00)103.25) 88.50)73.75/59. 00/44. 25/29 .50)14. 75)/144 15 ||150 00/135 .00)120.00}105 .00} 90.00/74.00/60 .00)45 .00/30 .00)15 .00))15 15}}}152 .50/137. 25)122.00) 106.75} 91.50)76. 25/61 .00)45 . 75/30 .50) 15. 25)/153 -154)|155 .00}139.50)124 .00) 108.50} 93.00/77 50/62 .00/46 .50/31 .00)15 .50|/154 153/157 .50)141 . 75}126 .00/110.25| 94.50/78. 75/63 .00/47 . 25/31 .50/15 . 75|| 153 16 ||160.00/144.00)128 .00/112.00) 96.00/80.00)64.00/48 .00/32.00)16 .00/|16 16})|162.50/146 . 25/130.00/113.75| 97.50/81. 25/65 00/48 . 75/32.50)16 .25}|164 164}|165 .00)148 .50)132.00)115 .50| 99.00)82.50/66. 00/49 .50)33 .00)16 .50 16k 163/167 .50/150. 75|134.00)117.25|100. 50/83 . 75/67 .00/50 . 25/33 .50)16. 75/|16 17 ||170.00)153.00)136 .00)119.00)102.00)85 .00/68.00)51 .00|34.00/17 .00)|17 17}}|172 .50)155 . 25}138 .00)120. 75)108 .50)86. 25/69.00/51 . 7534 .50)17 .25)|174 174||175 .00|157 .50)440 .00)122 50) 105 .00/87 .50)70..00)52 .50/35 .00/17.50)|173 173||177 .50)159 . 75)142.00)124 25/106 .50 87.75/71 .00)53 . 25/35 .50)17.75||173 18 ||180 .00/162.00}144 00/126 .00/108 .00/90.00|72. 00/54. 00/36 .00)/18.00}|18 18})|182 50/164. 25/146 .00/127.75/109.50/91 . 25/73 .00|54.. 75|36 .50)18 . 25)/184 183|/185 .00)166 .50)148 .00/129 .50)111. 00/92 .50}74 .00/55 .50|37 .00/18 .50)/183 183|/187 .50)168. 75/150 .00)131 .25)112.50/93.75 75.00/56 25 37 50/18. 75|/189 ——— | ee ee ee tel 1,000} 900 | 800 | 700 | 600 | 500 | 400 | 300 | 200 | 100 274 Testing Milk and Its Products.’ lable IX. Amount due for butter fat (Continued). 1,000} 900 | 800; 700} 600} 500 Price per pound, cents. Pounds of butter fet. 400 | 300 | 200 | 100 ‘punod Jod 90,1g "$720 cm | | | ff SSS SS _ _t > | $ | $b] $ $ $ $ $ $ 19 ||190.00)171 .00}152.00)133.00)/114.00) 95.00 194}}192 .50/173. 25/154 .00/134 . 75/115 .50} 96.25 193})195 .00)175 .69/156 .00}136.50)117.00} 97.50 193)/|197 .50)177 . 75/158 .00/138 . 25/118 .50} 98.75 20 ||200.00)180. 00/160 .00)140 .00/129 .00)100.00 20}}|202.50}182. 25/162 .00)141.75)121 .50)101. 25 2031|205 .00}184 .50/164.00)143 .50)/123 . 00/102 .50 203/207 .50)186 . 75/166 . 00/145 . 25/124 .50)103 .75 21 |}210.00)189 . 00/168 .00)147 .00)126 .00)105 .00 213)/212 50/19] .25)170 .00)148 . 75}127 .50)106 . 25 213)/215 .00/193 . 50/172 .00)150 .50/129 .00/107 .50 21$||217 .50/195 .75]174. 00/152. 25/130 .50)108. 75 22. |/220.00/198 .00/176 .00)154.00/132.00/110.00 224/222 .50)200. 25/178 .00)155 . 75/133 .50)111. 25 22$)|225 .00)202 .50/180.00)157 .50/135 . 00/112 .50 . 223||227 .50/204.. 75/182 .00)159 . 25/136 .50)113.75 23 ||230.00/207 . 00/184. 00/161 . 00/138 .00/115 .00 2341232 .50/209 . 25]186 . 00/162. 75)139 50/116. 25 234|/235 .00}/211. 50/188 .00]164.50/141 . 00/117 .50 239(|287 .50/2138 . 75/190 . 00/166 . 25)142 .50/118.75 24 |/240.00)216 00/192 .00/168 .00/144. 00120 .00 243/124 50/218 . 25/194 . 00/169. 75)145 .50)121 . 25 2431245 .00/220.50/196 . 00/171 .50)147 .00)122 .50 243/|247 50/222 . 75/198 . 00/173. 25)148 .50)123 .75 76.00/57 .00/38 00/19. 77.00/57. 75/58 .50}19. 78 .00)58 .50/39 .00)19. 79.00/59. 25/39 50/19. 00 25 50}: YIP 00 25 80.00/60. 00/40 .00;20 81.00)/60.75/40 50/20 82.00/61 .50/41.00)20. 83.00/62. 25)41.50)/20 84.00/63 .00/42.00)21 85.00/63. 75}42.50)21 86 .00/64.50/43 .00}21. 87.00/65. 25)43 .50}21 . 88.00/66 .00)44.00)22. 89.00/66 .75|44.50)22. 90.00/67 .50/45 .00)22. 91.00/68 .25)45 50/22. 92.00/69. 00/46 .00)23. 93 .00)69 . 75/46 50123. 94.00/70 .50)47 .00)23 95.00)71 .25/47 .50)23. 96.00|72..00/48.00]24. 97 .00|72.75/48.50|24. 98 .00/73.50/49 00/24. 99 .00/74.25/49 50/24. 00 25 50 75 50) |: 75) |: 00)): 25)|: 50 754/24 25 |/250..00/225. 00/200 .00/175 . 00/150. 00)125 .00/100. 00)75 . 00/50. 00/25 . 00}|: —_ || ————————.- | —_—————_—_—_—_—_—._ | ——————_————__ |, ————————_ | | | | | | | es Appendix. 275 Table X. Relative-value tables. (See directions for use, par. 238.) ve} =| ba Price of milk per 100 pounds, in dollars and cents. ¢ Bee 2o0 cl rsd) 4-.30°|:.84.4 86° | .87 | .3 40 | .42 | .48 | .45 3.1 31 Bat coe }.56 4 .o0e) obo. | 40) 42 ).43 1 .45 | 46 3.2 32 | .84.] .85 | .87:| .88 | .40| .42 | .43 | .45 | .46| .4€ 3.3 AS45561. .50:4 .o07) Ad.) 44l 43 | .45 | .46 | .48 | .4¢ 3.4 34 | .86 | .87 | .89 | .41 | .42 | .44] .46| .48 | .49] .6] 3.5 Sle By kb oe) | 40°) 142.) 44 745.) W47,.|. .49 } 61 z 3.6 $6: .38.1 .40 | .41 | .48 | .45 |-.47 | .49 | .60 | .62 | .54 es 37 | .89 | .41 43 | .44] .46 | .48 | .50 |] .52 | .54 5 3.8 BeeeaOsl.42 1.44) 46°) 47°] .49-) 251.) 258. | 655.) :.67 3.9 39 | .41 AS, Ap | - Ad |, .49.)..51 a7 1.60.) .b7 | SBE 4.0 40 | .42| .44]| .46]| .48 | .50] .52 |] .64 | .566] .58 | .6C 4.1 41 43 AR ee A gee) Ok ioe) sooner |-.60 [i.61 4.2 42 | .44] .46] .48/] .50] .52 | .55 xe}, 681.61 Z 4.3 43 | .45 1 .47 | .49 | .62°|..54 | .56 7] .68 | .60 | .62 | .64 4.4 aay) 146°1.248}. 61.) 63 255.) .67 | .69. |. .62 | .64 | .6€ 4.5 45 | .47 | .49 | 62 | .54} .56.) .68.|..61 | .63 } .65 | 6% 4.6 a ae kot need eo sone 60) .62 1 »64 | :67 4'.6 4.7 47 | .49 | .62 | .64]| .56 | .59-] .61 63.) 6671 °:,68.) 7 7G 4.8 48.) .60.) .63.} .55 | 58 | .60: | ..62.).65 | .67 Wt She 4.9 49 | .51 54 | .56 | .59 | .61 64 | .66 | .69 71 73 5.0 60} .62 | .65.| .57 | .60 | .62 | .65 | .G67 70} .72| .76 5.1 BL) 64) .66 1 .69: | .61 | .64.| :66 ]) .69 | .71 74 | .7€ 5.2 ao. |be:)- 67 1-260 | .62-1°.65 | .68 70 73 To oe 5.3 53 | .56 | .58 | .61 64-1 -.66°} 269: ) .72)) .T4c)..77 7 5.4 54 | .57 | .59 2] .65 | .67 70 fee a ae A ed a 5.5 55 | .58 | .60 2) ,66 | ..69)| .71 ep ot I Ue 5.6 Bo-1e500 |. 6241 .642).60.+ .70,| 273 7G.) 28 81 84 5.7 57 60 | .63 | .66 Goi et Lda ek Ft OU eo |. 85 5.8 58 | .61 64 | .67 fh bs Nagey pl ew 78 | .81 84 | .87 5.9 59 2 | .65 | .68 Mi heviae (ak dee Two | .86, 588 6.0 BOn 20a) 266") s69 72 75: | 78 1 Bl is. 84 | 2874 90 276 Testing Milk and Its Products. Table X. Relative-value tables ( Continued), a . Oo Price of milk per 100 pounds, in dollars and cents. m4 3.0 46 48 49 BL b2 54 55 57 58 3.1 48 50 51 53)| —.54 56 57 59 60 3.2 50 ol 53 541 .56 58 59 61 62 3.3 51 53 54 56] .58 59 61 63 64 8.4 53 54] .56 58 | .59 61 63 65 66 8.5 54] .56 58 59 | .61/] .63 65 66 68 8.6 56 58 59 61; .63 65 67 68 70 8.7 57 59 61 63 | .65 67 68 70 72 8.8 59 61 63 65} .66 68 70 72 74 3.9 60 62 64 66 {| .68 70 72 T4240 4.0 62 64 66 68 | .70 12 7T4| .76 78 4.1 64 66 68 10. \2.¢2 74 76 78 80 4.2 65 67 69 T aes 76 78 80 82 4.3 67 69 7a (Ey rer es 77 80 82 84 4.4 68 70 73 5a feed 6 79 81 84 86 4.5 70 (2 74 761 .79 81 83 85 88 4.6 71 74 76 78 | .80 83 85 87 90 4.7 73 75 78 80} .82 85 87 89 92 4.8 74 17 79 82| .84] .86 89 91 94 4.9 76 78 8] 83} .86 88 91 93 96 5.0 77} .80 82 85 | .87]| .90 92 95 97 Gat 79 82 84 87 | .89] .92 94 97 99 5.2 81 83 86 88} .91] .94] .96 99 | 1.0] 5.3 83 85 87 90; .93] .95 98 | 1.01 | 1.08 5.4 84] .86 89 92; .94| .97 | 1.00} 1.03 | 1.05 5.5 85 88 91 93} .96!] .99 | 1.02 | 1.04 | 1.07 5.6 87 90 92 95} .98] 1.01 | 1.04 | 1.06 | 1.09 Biaxk 88 91 94} .97 | 1.00 | 1.03 | 1.05 | 1.08 | 1.11 5.8 90 93 96 99 | 1.01 | 1.04 | 1.07 | 1.10 | 1.13 5.9 91 94 97 | 1.00 | 1.08 | 1.06 | 1.09 | 1.12 | 1.15 6.0 93 96 99 | 1.02 | 1.05 | 1.08 | 1.11 | 1.14 | 1.17 Appendix. : 277 Table X. Relative-value tables (Continued). =| : oa Price of milk per 100 pounds, in dollars and cents. fa 3.0 61 .63 64 .66 .67 .69 70 12 73 75 3.1 .64 .65 .67 .68 .70 yf .73 .74 .76 78 8.2 .66 .67 .69 Pai i Usp Peat fe 74 .79 ak .78 .80 3.3 .68 .69 a: 13 .74 .76 .78 <0 81 .83 3.4 70 71 73 75 | 78 80 2 83 85 3.5 72 73 75 77 .79 .80 82 84 86 88 3.6 74 76 77 79 81 83 85 86 88 90 a | 76 78 80 81 .83 85 7 89 91 93 3.8 78 80 82 84 .85 87 89 91 93 95 3.9 80 82 84 86 .88 90 92 94 96 98 4.0 82 84 86 .88 .90 92 94 .96 .98 | 1.00 4.1 84 86 .88 . 90 .92 94 .96 soe) ON Aa O8 4.2 86 88 .90 .92 94 97 a tok OF, 1 208 1-205 4.3 88 90 .92 .95 97 99°) 1.01 | 1.03 | 1.05 |.-1.08 4.4 90 92 .95 97 9954) F301 E08") F206.) 1.084-1.10 4.5 92}; .94 OT 238) 1 OT 108 1106 0508) 1.10-} 1513 4.6 .94 .97 69. 2 -OL-trines £42064 1.08.1: 1.105 1519 (7 LAG 4.7 .96 O9 li1, 01.) £08) ) 2206, ).1208 h L340, 2.19) 4.15 |) 118 4.8 age. teb OL, 10a; | 1.06.) 0208 11.10.) 1,43. | 1.15". 2.18) )-1.20 4.9 || 1.00 |} 1.03 | 1.05 | 1.08 | 1.10 | 1.13 | 1.15 | 1.18 | 1.20 | 1.23 Sons 0c t-1.05:}. 1.07 | E10.) 2.92 [0 15-) F186} .20.)- 1.23 | 1.25 Bee aa beOT bl tO ae 1 te. De 4.20. 222) 1.25 | 127 omeeatc? 11700. 12018.) PAT ETT ab 20 122 1-12.25) 11 27 | 1.30 Been ateooy) 4. fk.) date |) 297 19 1.22"). 9. 2) |. 2.27-1°1.80 | 1.32 Peete Ct ae 6 Pode | Wel) tA 274280 71282 | 1.35 Pemeabets oreo 1218") bo 2) oh 24 11.26.1529 | 1.382) 186 | 1.38 Beg acta.) 2.18.1-1.20 | .234) 1.26 | 1.29'| 1:382-) 1.8 1.37 | 1.40 Gee iii le (tee0 | 1.25 7 2.257) 1-28 | 1.8h 11.34 | 1.37 | 1.39°| 1.48 born L.19-|. 4.22 |. 1.25 |.1,28 | 1.30 }.1.33.|.1.36 | 1.389 | 1.42 |. 1.45 Reade) bed ad re es dese (1536. 139°) 1.42.) 1.45 | 1.48 ra ae i 26 |) 29 | Tea) ft so7f 188 Ab | 1440) 1.47 | 1260 Testing Milk and Its Products. 278 Table X. Relative-value tables (Continued). Price of milk per 100 pounds, in dollars and cents. “783 “U9 19, [ SMO aN Oetr SMaOaON a Ly SAMO ON OQeatr FOARD OS SSnam NANNN COCOHH SH 19191919 OPN ee SSS SRN RON ORR ORR Oster S DOEBDNDG OAetro | LOnog Qo Qeatr DOEADBO COOH AANNSH Sr Hig 1919 1 OOO ee be oe eee oe oe ee ee oe oe eh nh rOoMmoeomD wstrOom OON1900 eee LO ae ae © A119 OH DARAAP OOO FAAANN 0000 Wig wig OOOOrmI Se ee ee ee eo oe ee oe eo | ec ain eal SMM Anm trod so ear ul pS) NESE alias ~rontwoorn DODD COSOCOm RHAANNG 1 CD 6) OD =H Wigid WOOO Or Sess ee oe eee I es ee Ss area et +i OAN19 Oomanmoasd 119 OD © oD OA str —aisaiiveylc oft = tt ON190 @ DDPePPD AHBOSSG AAANN ANMOO Hutton wWi9nsods ee ee ee ee oe oe eel el eee he hn CD Om oO ONH OFDM HOSORMND LFPOMDH HHtrRoOnn DDDOD HBHOSSG AenAAN ANNMSH MNHHtSeH wnmmpTsd ee eG ee Sage ie aly ee OLE Le ae ee Os LORE CI 1 0red Tete’. CA eiet eyte e! 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