THE TESTING OF MILK.

Dominion, Volume 4, Issue 955, 24 October 1910, Page 10

THE TESTING OF MILK.

A METHOD. Almost every farmer is just at present interested- in the testing of milk. For those who. havo undertaken .or propose to. undertako the work privately tho following,' by H. E. M'Natt (Missouri College: of Agriculture), in "Hoard's Dairyman," should bo .valuable: — Tho" milk of every cow varies in fat content .from milking to milking and from day to day. For this reason a jnixed sample • covering several days is necessary to givo a fair average-of her milk. ■ The sample tested should be an average of at least six . milkings, and better even more. -In taking the sam;plos, froniv.tlie'. individual cows, proceed as follows£MX ■ ■': Procure as many sample jars (ordinary pint Mason v fruit jars are good) as t there- are cows -boihg milked. Paste a 'label; upon each''''jar; upon which is written the ,name ori.number of the cow. ..'Be sure the jars are provided 'with -the usual rubber rings to make them air tight. Drop fifteen drops of formalin into each jar to preserve the milk;-/Formalin; may ,be. obtained : from nearly any druggist. Put the jars with lids screwed on tightly in a safe place convenient;...to .' where; tho, .milk is strained. After a. cow is milked, mix the milk in'the pail by,stirring or pouring into .another, vessel.. .;Tal;c ai'saniple but with.a small dipper made by soldering a piece of'wire to a brass;shot gun. 'shell:-; Bo sure; the "dipper.'is full of milk. '•' Pour the contents of the. dipper jrito'.the. jar,bearing tlie name of the animal whose milk.' is being samp>d. Screw tlie, lid on tightly. ..Do..the same .with each'cow's milk./..Repeat the pro-., ■cess-, 'during the least six ■; consecutive milkings.. ;,/ ;' ■'-■ Shake;the''-jars,gentlyjeach'day so as 'te" : preventvtho/cream---ffom hardening and; sticking/to the sides of the' jar. Do not, however, shako-bard enougb. .to:-churn the'.milk;■ „'j ; \ • ■'. ,■. ;' Tosting. ■'.;;' , ./' '~ ■ :;:; The apparatus necessary to make- a 'test 'is as follows:"—-Attesting, machino or, centrifuge; a millo > pipette of .17.6 c.i/c; (capa.brty; tmilk-.bottles. and .acid measure of r 'l7.6vc;'''o..',capacity.; !and a pair, of dividers.: An. entire large fhpugh'Uof *a-»herd/of not 20, cows ban.- be /purchased dollars to 9.00 dollars. ■', 'In'-usiug the /'pipette; it -will be found convenieiit'::to'push a' piece '0f... piiro .gum.,.r,ubbpr' tubing- over, the large 'end .df'.the Jpjl*tte .about 'blie-' half'*iuch, leaving about,''one;.inch/projecting.,/ Ordinarily; .no, rubber tubing is, used;' ( .thn.pressure,of the finger .on. .tli'e.eiid-vof '> the': pipette;>.regulating the outflow .of.the milk: • ■'" .' : ■:'■/' ]'■''■' ;,..• Thoroughly : mix the sample v to".- bo .Vested By .pouring '~bacE''End'forth.from tlie sample -jar' to -a clean cup or jar. at -least; six- times and -until,no fat is left adhering to .'the, walls of the sample jar/ - Be' careful nc-t to .spill..any,..of. iho ;'milki Draw .the ] pipette nearly 'full, of 'milk .by; sucking with the lips. Squeeze ;the rubber tube-above the. glass iintll fthe'./milk,"'is' : held;when /the ,lips ir.eVremovecl:/;,Allow the milk to escape 'by.vvarying tho, pressure on ithe .'rubber .tubp-ittritil : the 'mark: on' the pipette is reached. 1 ''.Transfdl' -the]* milk carefully to !pne of tho test bottles: Mark the ■ number -'..or name of the cow on/the >small-'ground.'spot,.-on the bottle.',Bo sure all/the milk -runs'., out 'of 'the pipetteV;/;' ;:i''. : ;;;/v ; - v /-,.;, [■) ;-,'■;''.;'. .'is a'igbod plan; t'o measure out two sariiples'forbach cow;;in case one bottle iihould. be ;broken; while; making. the' test'. ;:The reading on. ; the two, bottles should, not vary oyer ono small space or .2/ per cent. Have, spine scalding". hot -water convenient,.;/ ■' : j,,..,;; .',■■;''.l-V, jv /;,;.; ; ~,;,;:■;.;./.;;; ./.Commercialvsulphuric : acid -, is ..used." Tliisim'fty 'be;obtained from any druggist or in larger quantities,from a creamery supply : liouse. /'',' ■/"-!- .'■-..-; ■':' : - ■~. ; •Fill the acid, measure up to the mark, and pour'.into-tho tost bottle. '.Hold the, bottle in a slanting position so that the acid will run down the ■ necks and,under tlie-"milk.'.'' Rotate 'tho;:bottl© slightly..' . while' pouring nF the' acid to wash down any. milk that;adheres to ,tho insido.of theftieck. JVhen fthe acid is ; added, mix tlie'';milk-'and acid'wifch'.'a.gentle rotary motion,'taking care to'prevent slopping ..the/,mixtufe into\.the fueck.-,'■ Mix. until aU-.itliei'white'•■curd.x-h'asi.becn dissolved,, arid imtil/tho liqviid' in/iiie bottlers of'a. brown colour, - ■■■;' ■' ; ■ .;•'.'. I, ; ; .-, When.the acid has been added to,all anil mixed, the bottles are placed in the centrifuge, • arranging them., so as ,to. balance.-'. Whirl at' the speed, given in tli-b : directions that come with the machine.;.''.■'.'■''.;',-. , •',- ;'.- Nearly, all hand machines-.ar© built to run •.■from'' eighty .to ono' hundred turns of; the: crank per -ininute. Whirl for five; minutes.- . Stop ..the [ machine gradually;'/,Add hot water to tho bottles .with the pipette : until.each is full to the base "of. the.heck. Whirl;again for two : minutes and stop.' "Add more hot water, until.,the, neck ,of each, bottle is full jto -within : ani.inch.-of ,-the/top.. - Whirl again-fpr, .one minute. Reading the. Test. /The :neck of-/tbo-standard,milk test, bottle is divided into, tenlarge divisions; and.each of the latter, into five /.small divisions.-, -Each- largo division is one per cent., and* each small'''division twotenths .of ohe-per cent.; If the butter-fat-fills thfeo large'spaces there is three per centi of'fat; or. three pounds of fat to the;: hundred. pounds or. milk) and would be/written 3 per .cent, vlf the fat

column covers five large and two small spaces tho reading would. bo fivo and four-tenths, written 5.4 per cent. _ The dividers are used to conveniently measure tho length of tho fat column. To do. this tho extreme .length is taken by placing one point at ! each extremity of tho fat column. Then without disturbing tho "spread" of tho dividers, one point is placed at tho line on;bottlo neck marked with 0, and the reading made where the other point touches tho scale. This method enables one to read tho per cent, of fat easily and accurately. Cautions and Remedies. If a sample coagulates before testing, start a new one, adding a few drops moro formalin than at first. Sulphuric acid destroys clothing and burns the flesh; so handle it with care. If spilled on tho hands, wash off with water at once. ... . Keep the bottles hot while testing, and thoy must bo hot when the reading is taken. If they become cold, placo them in'', hot water up to within an inch of tho top of the neck; and leave for five minutes before reading. ': If tho test has been properly, conducted, the fat column will be clear, with no sediment present either : below or above. ;;If a white chcesoy; sediment shows under the fat column, use a little more acid'next. time. ; White team on top of .the-fat column is usually caused by : hard water, and may be avoided by using rain water. If the fat column is dark or has black sediment; below the fat, use less apid or cool the : milk. ' • , . • , Keep .the acid bottle tightly stopped with a.'glass or rubber stopper, as sul'phurfc acid absorbs, water from the air, and consequently becomes weaker. In emptying test bottles, ,first, pour out one-half the contents and shako the remainder vigorously to. loosen the : sediment'on the bottom of the bottle. This .saves labour .in cleaning the' bottles,;as the sediment is very difficult tojremove: if allowed to dry on the bottom of the bottle., ■■ ■'' . > Keep ,■ the heck of the test bottles clean with a brush. : - • . ' It-'is advisable, to keep a few extra bottles,.ono.or two extra pipettes arid acid measures on hand.. ~'■;■'