EQUIPMENT OF THE 

DAIRY The improved •form of milking-pail shown in fig. r has rests or brackets, which the milker when seated on his stool places on his knees; he thus bears the weight on his thighs, and is entirely relieved of the strain involved in gripping the can between the knees . The milk sieve or strainer (fig . 2) is used to remove cow-hairs and any other mechanical impurity that may have fallen into the milk . A double straining surface is provided, the second being of very fine gauze placed vertically, so that the pressure of the milk does not force the dirt through; the strainer is easily washed . The cheese tub or vat receives i Market butter is sometimes deliberately over-weighted with water, and a fraudulent profit is obtained by selling this extra moisture at the price. of butter . the milk for cheese-making . The rectangular form shown in fig . 3 is a Cheshire cheese-vat, for steam . The inner vat'is• of tinned steel, and the outer is of iron and is fitted with pipes IIVul11~!G IIIIII!Illl~lil!I!I111111llllilllllillllllllllNllllillfl~hlh!~~~' nie;nmrnrnuinnnui - . ~` ---- ~_ ~a. ill for steam supply . Round cheese-tubs (fig . 4) are made of strong sheets of steel, double tinned to render them lasting .

They are fitted with a strong bottom hoop and bands round the sides, 1illu lilli- IIIIIIIII111111 " VIII 1'' 1111111-";'i III IutuudllU ~ ' ~ III _ . 11 11,,1 • .. I_I I%I

Ili ! ~Illilh` and can be double-jacketed for steam-heating if required . Curd- knives (fig . 5) are used for cutting the coagulated mass into cubes in order to liber- ate the whey . They are made of fide steel, with sharp edges; there are also wire curd-breakers . The object of the curd- mill (fig . 6) is to grind consolidated curd into small pieces, prepara- tory to salting and vat- ting; two spiked rollers work up to spiked breasts . Hoops, into which. the curd is placed in order to acquire the shape of the cheese, are of wood or steel, the former being made of well-seasoned oak with iron bands (fig . 7), the latter of tinned steel . The cheese is more easily removed from the steel hoops and they are readily cleaned .

The cheese-

press (fig . 8) is used only for hard or " pressed " cheese, such as Cheddar . The arrangement is such 75 that the pressure is continuous; in the case of soft cheese the curd is merely placed in moulds (figs. t and to) of the required shape, and then taken cut to ripen, no pressure being applied . The cheese-room is fitted with easily-turned shelves; on which newly-made " pressed " cheeses are laid to ripen . In the butter dairy, when the centrifugal separator Is not used, milk is " set " for cream-raising in the milk-pan (fig . II), a shallow vessel of white porcelain, tinned steel or enamelled iron . The skimming-dish or skimmer (fig . 12), made of tin, is for collecting the cream from the surface of VIIII(IIIIVUillill "11':'NWINp :'I,:!II YlulitLillli'IiiliilYi1 (Pont.l'Eveque) . the milk, whence it is transferred to the cream-crock (fig . 13), in which vessel the cream remains from one to three days, till it is required for churning . Many different kinds of churns are in use, and vary much in size, shape and fittings; the one illustrated in fig . 14 is a very good type of diaphragm churn .

The butter-

scoop (fig . 15) is of wood and is some-times perforated; it is used for taking the butter out of the churn . The butter-worker (fig . 16) is employed for consolidating newly-churned butter, pressing out superfluous water and mixing in salt . More extended use, however, is now being made; of the " D) laiteuse " butter dryer, a centrifugal machine that rapidly extracts the moisture from the butter, and renders the butter-worker unnecessary, whilst the butter produced has a better grain . Scotch hands (fig . 17), made of boxwood, are used for the lifting, moulding and pressing of butter . In the centrifugal cream-separator the new milk is allowed to flow into a bowl, which is caused to rotate on its own axis several thousand times per minute . The heavier portion which makes up the watery part of the milk flies to the outer cir- cumference of the bowl, whilst the lighter particles of butter-fat are forced to travel in an inner zone . By a simple mechanical arrangement the separated milk is forced out at one tube and the cream at another, and they are collected in distinct vessels . Separators are made of all sizes, from small machines dealing with ro or 20 up to loo gallons an hour, and worked by hand (fig . 18), to large machines separating 15o to 440 gallons an hour, and worked by horse, steam or other power (fig .

19) . Separation is found to be most effective at temperatures ranging in different machines from 8o° to 98° F., though as high a temperature as 150° is sometimes employed . The most efficient separators remove nearly the whole of the butter-fat, the quantity of fat

left in the separated milk falling in some cases to as low as o• r . When cream is raised by the deep-setting method, from 0.2 to 0.4% of fat is left in the skim-milk; by the shallow-setting method from o•3 to 0.5% of the fat is left behind . As a rule, therefore, " separated " milk is much poorer in fat than ordinary " skim " milk left by the cream-raising method in deep or shallow vessels . The first continuous working separator was the invention of Dr de Laval . The more recent invention by Baron von Bechtol- sheim of what are known as the Alfa discs, which are placed along the centre of the bowl of the separator, has much increased the separating capacity of the machines without adding to the power required . This has been of great assistance to dairy farmers by lessening the cost of the manufacture of butter, and thus enabling a large additional number of factories to be established in different parts of the world, particularly in Ireland, where these disc machines are very extensively used . The pasteurizer—so named after the French chemist Pasteur —affords a means whereby at the outset the milk is maintained at a temperature of 17o° to 18o° F. for a period of eight or ten minutes . The object of this is to destroy the tubercle bacillus, if it should happen to exist in the milk, whilst incidentally the bacilli associated with several other diseases communicable through the medium of milk would also be killed if they were present . Discordant results have been recorded by experimenters who have attempted to kill tubercle bacilli in milk by heating the latter in open vessels, thereby permitting the formation of a scum or " scalded layer " capable of protecting the tubercle bacilli, and enabling them to resist a higher temperature than otherwise would be fatal to them . At a temperature not much above 15o° F. milk begins to acquire the cooked flavour which is objection-able to many palates, whilst its " body " is so modified as to lessen its suitability for creaming purposes .

Three factors really enter into effective pasteurization of milk, namely (I) the temperature to which the milk is raised, (2) the length of

time it is kept at that temperature, (3) the maintenance of a condition of mechanical agitation to prevent the formation of " scalded layer." Within limits, what a higher temperature will accomplish if maintained for a very short time may be effected by a lower temperature continued over a longer period . The investigation of the problem forms the subject of a paper' in the 17th Annual Report of the Wisconsin Agricultural Experiment Station, 1900 . The following are the results of the experiments:—1 . An exposure of tuberculous milk in a tightly closed commercial pas- FIG . 18.—Hand-Separator . teurizer for a period of ten minutes destro'ed in every case the tubercle bacillus, as determined by the inoculation of such heated milk into susceptible animals like guinea-pigs . " Thermal Death-Point of Tubercle Bacilli, and Relation of same to Commercial Pasteurization of Milk," by H . L . Russell and E . G . Hastings . llllill',q'f!;i!IIII'Ilf llll !

Ilidl!III IillU~~lllllllll!IIIIMilillllli .~,~nyllimn ill~ill', (FIG . 17.-Scotch Hands . 2 . Where milk is exposed under conditions that would enable a pellicle or membrane to form on the surface, the tubercle organism is able to resist the

action of heat at 14o° F . (6o° C.) for considerably longer periods of time . 3 . Efficient pasteurization can be more readily accomplished in a closed receptacle such as is most frequently used in the commercial treatment of milk, than where the milk is heated in open bottles or open vats . 4 . It is recommended, in order thoroughly to pasteurize milk so as to destroy any tubercle bacilli which it may contain, without in any way injuring its creaming properties or consistency, to heat the same in closed pasteurizers for a period of not less than twenty minutes at 140° F . Under these conditions one may be certain that disease bacteriasuch as the tubercle bacillus will be destroyed without the milk or cream being injured in any way . For over a year this new standard has been in constant use in the Wisconsin University Creamery, and the results, from a purely practical point of view, reported a year earlier by Farrington and Russell,' have been abundantly confirmed . Dairy engineers have solved the problem as to how large bodies of milk may be pasteurized, the difficulty of raising many hundreds or thousands of gallons of milk up to the required temperature, and maintaining it at that heat for a period of twenty minutes, having been successfully dealt with .

The plant usually employed provides for the thorough filtration of the milk as it comes in from the farms, its rapid heating in a closed

receiver and under mechanical agitation up to the desired temperature, its maintenance thereat for the requisite time, and finally its sudden reduc- tion to the temperature of cold water through the agency of a refrigerator, to be next noticed . Refrigerators are used for reducing the temperature of milk to that of cold water, whereby its keeping properties are enhanced . The milk flows down the outside of the metal refrigerator (fig . 20), which is corrugated in order to provide a larger cooling surface, whilst cold water circulates through the interior of the refrigerator . The conical vessel into which the milk is represented as flowing from the refrigerator in fig . 20 is absurdly called a " milk-churn," whereas milk-can is a much more appropriate name . For very large quantities of milk, such as flow from a pasteurizing plant, cylindrical refrigerators (fig . 21), made of tinned copper, are available; the cold water circulates inside, and the milk, flowing down the outside in a very thin sheet, is rapidly cooled from a temperature of 1400 F. or higher to I° above the temperature of the water . The fat test for milk was originally devised by Dr S . M . Babcock, of the Wisconsin, U.S.A., experiment station . It combines the principle of centrifugal force with simple chemical action .

Besides the machine itself and its graduated

glass vessels, the only require- ments are sulphuric acid of standard strength and warm water . The machines—often termed butyrometers— are commonly made to hold from two up to two dozen testers . After the tubes or testers have been charged, they are put in the apparatus, which is rapidly rotated as shown (fig . 22); in a few minutes the test is complete, and with properly graduated vessels the percentage of fat can be read off at a glance . The butyrometer is extremely useful, alike for measuring periodi- cally the fat-producing capacity of individual cows in a herd, for rapidly ascertaining the percentage of fat in milk delivered to factories and paying for such milk on the basis of quality, and for determining the richness in fat of milk supplied for the urban milk trade . Any intelligent person can soon learn to 16th Rcpt . Wis . Agric . Expt . Station, 1899, p . 129 . l !

[Il111ll ililllllilllll~ . --1-1i _Iillli11i 11111111111111NII i `11II Ili I Ifl I ,I Illlllilllllllllllllllll!IIIIII~~ilml !! ~ ~!il!I~illll,4'll!II!III!I1611Po pll` , work the apparatus, but its efficiency is of course dependent upon the accuracy of the measuring vessels . To ensure this the

board of agriculture have made arrangements with the National Physical Laboratory, Old Deer Park, Richmond, Surrey, to verify at a small fee the pipettes, measuring-glasses, and test-bottles used in connexion with the centrifugal butyrometer, which in recent years has been improved by Dr N . Gerber of Zurich .