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BULLETIN 117 
 
 Ontario Agricultural College and Experimental 
 
 Jam 
 
 'fax 
 
 CO B9S 
 
 th; 
 
 HP CONTINUOUS PASTEURIZATION OF Mlf k' \T 
 DIFFERENT TEMPERATURES i'OR BUTTER MAKING; 
 
 By Pkof. H. H. Dean. B.S.A., and Pr„k. F. C. Hahrison. B.S.A. 
 
 The constant striving of ajrricultural countries to produce tlio Lest 
 articles at the lowest possible cost for the En^Hish n.arliets has res„ ted 
 in very keen competition, and new competitors are constantly entering 
 the held \\e have lately heard that Siberia is sendin.r considenTle 
 quantities of butter to England, and that special refrigerator trs 
 and steamers have been built in order to handle this product At 
 presen this butter, althoush good in texture and make, licks uniform 
 ity and flavor; but these defects will probably be spJe iily remeS 
 he Russians have lately sent expJrts to Denmirk, to stu v he 
 metho.ls toliowed in that country, and have even in.ported 'kil ed 
 dairymen tor the purpose of instructing the Siberian peasants. H -nee 
 it behot,ves the Janadian maker to take a.lvantage „f every new 
 method which IS shown to be of value in producing a tirst-class article 
 
 AS It has been the strenuous endeavor to cheapen pro<luction in 
 those countries which make a specialty of dairying, tfiere niust be good 
 grounds for their adoption of pasteurization, a,roperation whi^l^ i^- 
 creases the cost to a, considerable extent in the outlay, both for appara- 
 tus and for the production of the heat required in the operation^^ 
 
 Ihat buttermakers should incur this additional expense is verv 
 good evidence that pasteurization is an important operat on, and that 
 without It there is difficulty in obtaining the best results 
 
 Ihe comparison that has often been made between the farmer and 
 the dairy.nan explains the chief reason for pasteurization. The farmer 
 cultivates his land and prepares his soil for tho special crops he intends 
 to grow ; he eradicates as far as possible all weeds, and he selects with 
 
 sown. The dairyman also prepares his soil, the raw milk, bv heatine 
 It to such a temperature as will kill all or the greater number of bac- 
 teria which may be present, these being his weeds ; then I.e seeds his 
 milk with a selected varied, of mic.o-organism found to produce a 
 good flavor in butter ; and h also expects to reap even as he Ls s ,wn 
 These two points-Hrst, the preparation of the milk by pasteurizing.' 
 and, secondly, the seeding with selected races of bacteria-have enabled 
 al niakers to secure the great desideratum, unifom.iU, of product 
 which IS of such importance to both producers and consumera 
 
 [11 
 
 W 
 
l^ 
 
 In addition to this uniformity. th« l.utter-iniiker w mcKlontally 
 able to drive ott'crtain unpleas^vnt .)<l.)urH that nuiy be nre^ent in the 
 milic snpplitd to hiu. ; and the keeping .piality o his product m hereby 
 creasHi lH.cause he ban killed the hiryer nunda-r -d the harndul bac- 
 teria, wJuch, if they had ren.aiued living, nuKht have unpaired the 
 
 (lualitv of iii» butter. , ,, c ; . „« 
 
 Further, if the ri«ht temperature ih used, a\\ <hs,UHe.j>ro<h', >np 
 orgonlsn,. are destroyed, inch.din- the bacillus tuberculo«.H. wh.ch ,s 
 very fre.,uently found in l.utter. This fact alone wdl u-ld eonsi.lerably 
 to the coud'ort and security of the consuni.r. 
 
 The whole problem of pasteurization is a question as to the p'oper 
 temperature; and unfortui.ately this is a n.atter of so.ne complexity^ 
 The effect of temperature on bacteria depends ..n the.le^i.o ot 
 heat and the length of exposure.-a low de-rce ot heat and a Urn ex- 
 posure bein« e.,mvalent t.. a hi;,'her temperature ami .ho, ter exposure ; 
 Li the former takc.s too much tii.ie au.l is not pract.cahle, while the 
 latter is apt t.. yive a cooked taste to the milk. Hence we have tw 
 Im-thodsof pasreuri^in« f.>r two diri'erent objects, which have been 
 termed the Discontinuous and Continuous systems, 
 
 n. l);HC,>nflnunUHS>,.(nn,or a system of pasteurizinjj froiii the 
 milk-dealer-H Htandpoint, re.,uire.s that all di8ease-pro.luclI.^' 'acte'-ia 
 be destroyed, that the milk possess «ood keepin- .piabty and that the 
 taste b- not injured. In order to obtain these re-iuisites, the milk must 
 be hellln 1^0 decrees F.. be stirred durin, tl. process to preven 
 the formation of a pellicle, or scum, on the -urtace ; and be 'leld at 
 this temperature for 15 to 20 minutes. This t'jnipenvture /or th,> 
 length of time, has been found sufficient to kill the baeillus tubercul- 
 osis the most resistant disease-producinjr ^eim found in milk. 
 
 n,.Contni>um^ii>lxte.m, or a system ot pasteurization from the 
 butterinaker's standpoint, was Hrst introdu..-e.l by the Danes. By 
 this method, the milk H .ws in at the bottom of a vessel hef . . , 
 steam, is whirled against the .side, and (having reached the 
 temperature) Hows continuously from an outlet in the top. li u ■ 
 is to kill most of the Lacteria present in the milk. I .y a v, 
 actinent in Denmark, this temperature has been hxed at «\«2;-- -. 
 (185 .le.'rees F.,) as Dr. Bang has shown that the tubercle bacillus ,i 
 bacillus'^tuberculosis, is killed in milk heated to this temperature. By 
 this means the buttermaker gets ri.l cf bacteria that might subs- 
 quenth prove harinful, and pi^epares the milk for his selected bacteria, 
 Dr culture, as it is usually called. . • x 
 
 In Canada and the Tnite.l States, the usual pasteurizing tempe, - 
 Rtnre is 158 detrrees F., (70 .legrees C.) to 160 Degrees \ ., a temperatur.' 
 selected becaust bythe.liscontinuous system a cooked taste was impart- 
 ed to the milk at higher temperatures ; but, as pointed out b> .i 
 recent New York ExpJ^iment Station bulletin, the American expen- 
 menters went astray in their reasoning, " for the cooked taste is tl.^ 
 St of an exposure of hot milk to oxygen, and the cooked Havor do.-s 
 
 1 
 
 »isi.i:il 
 
not Httiich itsflf tenaci..usly t.. the f.it. ..n.| l.i.tt.r iiui.le fn.m liiirhly 
 
 heateij milk that may havi- n ' ' ^ *" ^ 
 
 churning' Iohcm this .flijoctional.lf fl 
 
 )r 
 
 «tx)ki'il tusti', iiiiiiu'<liat<ly after 
 avour ill u short tiiiie." 
 r<.i; HIS years Mm. Dairy Kepannu.nt of ih.- CoILm* has Jnieii 
 condnctii.j. experiments to .letenuii.e the effects of pasteui i/ati')n .,n 
 milk ami eream tor huttermukiny. 
 
 i«or'^" i'ri',?-^''* *'"■ '''''■'"'<^'-"'""t»'""ftl'<'<l«"f pftsfeuri/alion since 
 
 1«9«. amny.»<,we.,uote Iron, the aan.i;.! ivport ..f the Coll for 
 
 those two years : o ' " 
 
 "< )\viii!,' to the lick of s.iita'.le appliune.'"^, ni..st of o„r i-astenriz- 
 mj^expenments were con.inete.! l.y simply h.-atin;; tl..- cream eontuin.'.l 
 
 ;?,r.MroT''''^'^i "'.''' ^""^ '" " •'"•^ ^^"terl«lth)to ,i tempna- 
 
 ture ol l(,() .io^rees. In ahont 20 minutes afterwanls. tl ream was 
 
 coole.l to ripenin- temperature an.j the starter" was a.l-le.l " - 
 
 '• It has heen s.i;r<r,.ste(i that i.ast.-Mi-i/in;; tl,.. whole milk /w;„v- 
 separa M.i,' was pn.|eral.le to h.-afin- the cream an.i skim-milk ,.//.r 
 Hepaiatin- A vat of milk was heate.l to a temp..rat..re ran.'in.r IV„„, 
 !».. .K^rees to )H ,le«rees. ami half of it was s.-parat..!. The Mh^r hal 
 was then h..ate.l trom 1.50 cle;,.rees to UiO ' 1..,^,.,..., ..n.) s..parate!i 
 Al the I";*!!!.- was .lone in a vat l.avin^r a capacitv of al'.ut .SOO 
 pouiuls The chief rhthculty was in piever.tin- th. milk from eo.,l<- 
 mL' on the sides of the vat. Hy earefully nuuTatin,^ th.. ^tean. and 
 by keeping' ih.- milk in motion, this trouMe was lai^'ely pr..v,.nt.d " 
 
 The experimenis instituted at the l nlU;r., Dairv^in l!»01 were to 
 determine the (juality and keeping prop.-rty of hutter ma.le Iron, milk 
 pasteunzed at dirierent temperatures. I,, the hacteriolococal I.thora 
 tory, our attention was .lirected to the numlM.r and kin.l of t.icteria in 
 em lo' ed""'' "" " I*'**''""'''**'''" "< ^he dilK.ivi.t ten.p..ratures 
 
 Tests at the Wi.scon.sin Station, with the R..id pasteii.iz..r at tem- 
 pera ures between 1.50-105 deir.eesF. showed eon.si.lerahle variation 
 Ihe lowest number in the pasteniized san.ple was ,S7,400 bacteria i.er 
 c.e., and the h.^^hest 17,-)00,0<)0 per c.c.,-a verv wi I,. diHeience The 
 avera-e number left (14 tests) after pasteurizinsr, was about 1 NOOOOO 
 or nearly !t2 per cent, of the bacteria were destroye.1. But this hardly 
 represents the variation in the effect of the h.,.atin;r; for in some cas/s 
 40 per cent of the fwcteria surviv..!. 
 
 The Pennsylvania Station, whilst -rivinj,' no numerical .lata, states 
 that lieatin^r to this temperature (l.5.-,-1.58 de-rees) dostroved few if 
 any, ot the bacteria present in the milk." 
 
 The New York Experiment Station have fuller data on this poir.t 
 At l.o«,legre.ss >., they foun.l that the pasteuii/iiig action was v,.rv 
 nncertain, and that this temperature lies near the lower limit of the 
 killing effect of heat applied in thi.s way ; and. when operatinir a pas- 
 teurizer in ordinary practice, temporary reductions of temperature are 
 
 II i! 
 
•Imcwt sure to occur. Hence the kJlHnK effect below tVw teiii|)er»turo 
 
 in yAPV Bllfirh^* 1 Kt 
 
 ObaervationK by the same station were made at 170 .l.'>rre.'4 ¥., 
 and the renultH of panteiirization at this temperature ' ^howeil a hui - 
 prisinir rwhiction inth^. gerin life, and thin re<luctu>n woHaccou.pl.Hhe.l 
 with very nliRht variation on each of the 25 dayn on which the tenlN 
 were made. Thene t.^tn gave an average ot nly 117. with a maxi 
 mum of 2!)7 and a minimum of 20. living germs per c.c. in thepa^teur 
 
 Seven tents at the tempei-rttuie UMed in Denmark. 1M5 degreeHF. 
 gave an average of 1 1 ^ living germs per c.c; an.l. as the writers remark 
 •were it not for the fact that in the present state of our knowledge, it 
 in believed that a heating of milk to \Hn degreoH F in a continuous 
 pasteurizer, is necessarv to lemov all dang.!- of tuberculosis, the us. 
 of hOdegivcHi;. (I7C d.grees F»iu pasteurization tor J.utter-makiiiK 
 
 would leave little to be tlesired." , . ., • . . 
 
 Tin' Pant, arizern.— The pasteurizers used m the experiments 
 here were the " Rei<l " in March an 1 the first seven days in April, an.l 
 the " Li- er '• for the remainder of the season. 
 
 The Reid machine is driven with a Wit and. in addition t.. heatiii;.' 
 the milk, elevates it several feet Th. ...ilk is heated by m.ss.ng over 
 a Hteam heate.l surface, and it is kept in a circular i.K,tu.nby means .. 
 paddles which revolve in the milk. The w..Hknes.seH of the Re.^l 
 pasteurizer are . The difficulty of maintainuii? a uniform tempenitu... 
 and the fact that it requires a firm foundation .or the large machine. 
 Its strong point is that it not only pasteurizes the milk, but act*- as a 
 milk puinp tor lifting the milk from the receiving vat to the ■•'eP'V^ato'-- 
 the Lister maclune is driven with steam directly from the boiler 
 and is what is commonly calle.l a turbin.- pasteurizer. It does no 
 elevate the milk above the outlet near the top of . machine, and must 
 be placed above the separator in order to have the .ailk flow into th.' 
 separator. The milk for this machine was pumped from the receiving 
 vat directly Into the feeding funnel of the pasteurizer; and the 
 temperature of the milk, which was received at a temperature .)t 
 aboJt 60 degrees, was raised from 125 to 130 degrees wh.l 
 passing through the machine, when fed at the rate ot about 
 2 600 pounds of milk per hour. M.Ik which was heate.l ah...' 
 185 degrees, rec.uired a preliminary heating before entering tlu- 
 pasteurizer. The three weak points of the Lister machine a.o. 
 That it does not elevate the milk, that the centre bearing of the 
 paddles fills with milk if the machine is allowed to get to.^ tull, an.l 
 that the turbine has not at all times sufficient force to keep the ...ilk 
 in constant motion. The strong points of the Lister iire that i 
 occupies a small space, nu belt is required to run it. and no sp.ml 
 
 foundation is needed. c i i. u 
 
 The Danish Pasteurizer, invented by Fjord, has of late bee con- 
 siderably altered, because the Danes are now compelled to heat tr..- 
 
milk t<> 85 .lejjrt...M (•..«„ | the oM fnrin of npp«ratiiH in not c*i>able of 
 econoinically h. atm« the milk to this t.iniK.ratur... Thf impr(.vt.m,.nU 
 Are iiH followH : "^ 
 
 A Mcri.-H of rin«H nre Mohk-r.'.! on the hentimj Hurfuce of the wm- 
 teunzer. llu-se tiiikh hIo .e .lownwiii-.Is, ^Mvinij the »i>p«5*rance of 
 cftvcH arranjCHl concentrically aroun.l the he/iter. Thes. • inim gather 
 ami «he.l the water formed hy cn.lensation of th.^ steam on the heat- 
 inK Hurface; ,r thia water .l.|,osite.i ,i. « thick layer upon theHiirface 
 of the heater, is a U.| conductor, opposes the r-sistance. and enfeebleH 
 the penetration ot the heat to the milk, which is tiirown by the asrita- 
 tor apiinHt the inner surface of the heater. 
 
 The agitator httH al.s*) lH.,.n improved i.y the addition of horiz.mtal 
 piatcH on the paddle, t.) prevent the milk from takinK t«K) vertical a 
 movement m the pivsteurizer ; and this improvement helps to irive the 
 same temperature to all parts of the milk, and prevents frothing. 
 
 A thud unprovement \h an air cock fixed on the water-trap which 
 allows the air carried alon« into the steam jacket to escape 
 
 No (h.ubt the efficiency of the Lister and Reid msteurizers could 
 
 be increased considerably by attachinif the improven.ents suL'Lrested 
 
 by Prot Storch. of the Experimental LalK)ratorv of the Koyal Airri- 
 
 cultural and Veterinary Collejre of (.'.)penha<,'en. ' 
 
 Daiuv Data.— In our Dairy, the experinients con.Hi8ted of several 
 series . 
 
 Serie>> I. In the first, abcjut M.OdO lbs. of milk wa« mixed in a 
 receiving yat ( )ne-half of .several lots was separated at a temperat.ire 
 of about 90 degrees V .. and the oth-r half was pasteurized at tem- 
 peratures ol 140, ItiO. and l«o degrees K. 
 
 ^l>''»'» II- In this series, ,S,000 lbs of milk was well mixed. One- 
 half of .several lots was heated to 140 degrees F. before separating- 
 an.. >e other half was heated to IGO, IH.5. and l!)-> degrees ¥. 
 
 ^nex III In this series, (me-half of several lots wa.s heate<l to 
 IbO degrees, and the remainder to IH.t degrees 
 
 S^'t'is IV. In this sf.rifs, samples "of butt.'r made from milk 
 heated to 185 and 11)5 degrees were compared. 
 
 Sn-h'H V. In this lot. one vat of ab.nt .S.OOO lbs of milk wa.s 
 •lividefl into four parts During April and May, each of these parts 
 was heated to 140, KiO. 185, and 19.-, degrees respectively ; but durintr 
 March. July, and August, the temperature.s used were 90 140 IGO 
 and ]85 degree,s. ' ' 
 
 Setiex VI. In the last series, experiments conducted during 
 March un June, vats of milk were divid.'d into two lots. One part 
 was left nnpa.steurized, and the oth. r w.is pasteurised at about ifiO 
 degrees. 
 
 Boihr PrfA-«?v'— The boiler used for generating steam at the 
 i>airy is a 50 horse-power boiler situated about 50 feet from the pas- 
 teurizer. An average pre.ssure of 75 to S(» pounds was maintained as 
 tar as possible. When the steam pnssure was reduced below 70 
 
 If, 
 
 iS. , li 
 
poun.lii, it wrt-i .lirtJcHlt t.. iimin»*ln tli.- milk at IH.1 t.» lin .l.tfn>0H 
 without iclucintf t»i« ftwl. It in ..vi.l.nt tlmt. if i>»Mteiiri/,in4 »»i IHO 
 ilfKii'«'H i" prACtiMt^l, a liir;(»< l<.>iliT hikI »Um\y rttoaui i.r«M«ir.' will Jhj 
 nxiiiirtMl. , , , 
 
 Durinij the >.nr nwirly 100,004) 1»>h. of milk wer« um'.! in the ex- 
 periiuoiitH. Kor April rikI M.iy milk whs r.ctMv...l four tinu'H n wf.;k. 
 Thf aveniK" pt-m-ntjip- of fnt in th^' milk «>f the HrHt four M.-rii-M 
 riingwl from 'AM* to «.<.!». Th« t.'miHjrature of tho milk whmi ro- 
 cciviMl wiiM 40 to HO (U-Kn'.H in Marrh iiixl April. In May it wan 
 about :>!» .le«ivt.M. Jiuu' 6i» ih'«r«i>H, July .ui.l Au^'UhI «:> <|.';(re.'«. The 
 avera;:.' .ici.lity in th.' tir>tt four hitIoh, whi-n the milk whs .h.liv..rt'«l. 
 »ii.H.l7 to.lH percent. Th.avi'rft}?enci.lity of the cream at th.-tiim- the 
 cultniv for ripcninjr was achl.il, vaiitM! from OHH per cent for the l"tH 
 heated to ItiO .i -r.es to .IIH for the ht> heated to 140 .l.'«ree.s 
 Those heated to IH') <l. triers had an avoraKe acidity ol .114; and 
 thiwe lotH o» cream from milk heated to 105 dejree-. lH.f..re He|>arivtin« 
 had an averap- of .104 per cent, of acidity at the titne the culture was 
 wlded. At tlu' time ot ehurnin),', there was very little <liHerence in 
 the acidity of the ditlerent lots— heinjj from .'» to .0 jxr cent. 
 
 The perceiitaue of fat in the cream in th.- Hrnt four HerieM varied 
 from an averay«« oi 'Ml in the lotM separated at 14i> duu'n-.s to -'Hi] in 
 the lots separated at 195 dejrrees. There was practically no diHerence 
 in the fat lost in the skim-milk and huttrmilk, whether the milk wiw 
 separated nt 140, KiO iNri. or 195 deyiveH The skim milk avera-jed 
 one-tenth of one per cent, fat, and the hiittermilk avenijjod aUnit .15 
 per cent. fat. The temperature of the cream at the time the culture 
 wa,s adde.1 varied from 6('. to (IH dejrrees. The avera.-e tempeiature 
 for ripeiiinj,' the cream was ahout 05 de;,'rees for all the lots. Ihe 
 average churninj,' temperature was 49 dejjrees f..r all lots. Th.- aver- 
 age time required to churn the cream wa.s 41 iiiinuteH for th. lots 
 separated at 140 decrees, :{9 minut.s for the lots .separated at l«iO 
 dejjrees, HH minutes for the lots separated at 185 •lejjrees, aii.l 8t) 
 minutes for the lots separated at 1!>.') dejrrees. 
 
 The i)eicenta<:e of moisture and salt in the hutter were : L ii- 
 pasteurize«l, i;i.690 per cent, moisture and 2.1.') per cent. salt. Pasteui- 
 ized at 140 de- rees, the moisture ami salt were, re.spectively. 18 12>S 
 and 2 57 ; ••♦ " -"> de;;r.'es. 18.224 and 2.85 ; at l«.^ <le;riees. 18.994 and 
 2.55: a/l9i3 uegrees, 18 501 and 2.62. All the hut er was salted at 
 the rate of erne ounce of suit per pound of I. utter. 
 
 After workinjj, the hutter in the first four series was put into 
 pound prints and wrapi)eil in parchment hutter paper. < )ne print ol' 
 each lot was numbered by the buttermaker, when it was placed iii 
 cold storajje at an average temperature of 40 decrees. The prints 
 were scored by numbers, so that the scorer did not know what kind 
 of butter he was scorintj. Nearly all of the butter was .scored twice 
 — once when made about two weeks, and again when one month to 
 six weeks old. 
 
<V>ii.pari-«.ii of hutfr „«.!« frm,, iu,p„Mt..uri/...| ii,i|k with l.iit'^r 
 "'*''" '»•""■ ""'k »'"*t.'.l to I4(t. im, ari.l In:, .l.-^nTs. 
 
 No. of 
 
 Kind of BtiUvi 
 
 
 i 
 
 Is 
 
 <3I 
 
 i 
 
 i 
 
 fa 
 
 
 rnpa* rnriiad 
 
 I'Mtriirixml at IWiirgtt—. 
 
 t'n|jMti*uri«Mi 
 
 pMi«u*it«d k( 100 (li-KrcM , 
 
 ' ' rwnteiirixM) . 
 
 i'»';^iiri/*l At 18ft d^Kriwit. . 
 
 S9 H 
 41 3 
 
 
 87 I 
 
 24 ft 
 
 10 n 
 4\ .*. 
 
 2ft 
 20 
 
 1 
 
 U.l 
 
 14 ft 
 U » 
 
 04. S 
 
 •••ft.r 
 
 Ul L' 
 
 »4 N 
 
 Uft.B 
 
 Coinparison ofhuttn- ma.l.. fr,.,„ milk past.-urlz.".! ,»i UO .li-nwa 
 with butter niu.i*- fn.iii iiiill< heute.! to IfiO. \Hb, aii.i IJ»5 iU^'^rwH F. 
 
 !5 
 
 l*Mteuriz«<t at 140 d»((rw* 
 Paatfuriz-Hl at lAO dc^refii 
 
 PmUuH/.»<1 at 140 flecnwa 
 Paitearizaii at IR'. (I^^'re*-* 
 
 Pa«tanrl7«d at 140 <\ntnn 
 Paatfiiriz'd at 196 defrrnf* 
 
 
 24 U 
 
 14 
 
 11 
 
 Hi 7 
 'J3.» 
 
 3!» ti 1 
 «0 4 j 
 
 2.-. 
 
 as 
 
 14 
 14 1 
 
 iM.ft 
 
 I ! 
 
 4 
 
 14 8 
 
 24 H 
 
 14 » 
 14.3 
 
 1»4 
 
 Scnriiiu '.(' Si rifs J If, 
 
 Coinparison or b;tt, r nia.h i,< m ,„ilk pnsturized at 170 (i.-iire..s 
 th butter tiuKif froi.. ., ilk pastcuriz..! at 185 .|»Mrret;.s F. 
 
 10 
 10 
 
 Pa«teariz«d at 160 devrfei. 
 Pattear z>d at 180 deffreei. 
 
 40 7 
 
 41 U 
 
 3S 
 26 
 
 I 14 2 
 
 14 1 
 
 94 N 
 95.1 
 
 Scorinff uf Srrii'n IV. 
 
 LT made from milk pa.«s 
 
 milk pasteurize.1 at 19.'> <le;,'rees F 
 
 •^u^^'llP*"""'! "^ ''"^^''* ""'••''' *"•■"'» '"'"« lia.'steurized at 1S6 de-'ree 
 with butteriuude from •-"- ^ • ' ■'-- • I"- «->o ue^rtt 
 
 Pa«teurized at 1H5 degre«i . . . 
 Paatenrized at 196 degrep*. . . . 
 
 41 
 40.8 
 
 26 
 
 25 
 
 14 
 14 
 
 96 
 94.8 
 
 p- 
 
 i 
 
 i- 
 

 f. 1 
 
 In the fifth fleries, where vats of 3,000 lbs. milk were divided into 
 four different lots during April, May, July, and August the average 
 percentage of fat in the milk ranged from 3.7 to 3.H. The per cent, 
 of acidity in the lailk delivered was .17. and that of cream at the time 
 of adding culture was .09 ; and at the time of churning it was .55 for 
 the lots heated from 140 degrees to 195 degrees and .59 for the lots 
 separated at ninety degrees. The percentage of fat m the lots ot cream 
 rancred from 27.6 to 32. The percentage of fat in the skim-milk was 
 less^than one-tenth of one per cent, for all. The fat in the buttermilk 
 was about .15 per cent, for the pasteurized lots, and .25 for the un- 
 pasteurized samples. All the lots had the cultures added at an aver- 
 age temperature of 68 degrees, were ripened at 65 degrees, and were 
 churned at 46 degrees to 47 degrees. The average time required to 
 churn the unpasteurized lots was 47 minutes ; the 140 degrees lots, 40 
 minutes; the 160 degrees lots, 39 minutes; the 185 degrees lots, 3/ 
 minutes; and the 195 degrees lots, 42 minutes. 
 
 Scoring of Si-ries V. 
 
 Comparison of butter made from unpa-steurized milk and butter 
 made irom milk pasteurized at 140 degrees, 160 degrees, 185 degrees, 
 and 195 degrees. 
 
 No. of 
 
 Kind of Butter. 
 
 k 
 
 < 
 
 < 
 
 o 
 
 Is 
 
 I'm 
 
 u 
 
 Is 
 
 u 
 
 < 
 
 2 
 4 
 4 
 4 
 1 
 
 Unputeurized 
 
 Faateurizei at 140 dejfreea 
 
 Pasteurized at 160 degrees 
 
 Pafteurizp . at 186 deRrees 
 
 Pasteurized at 196 degrees 
 
 39.2 
 39 2 
 39.6 
 41.1 
 40.8 
 
 26 
 25 
 25 
 25 
 24.5 
 
 1 
 
 14.2 
 14.1 
 14.1 
 14.4 
 
 13,6 
 
 93.4 
 9» 3 
 93.7 
 95.6 
 93.8 
 
 i^i 
 
 In the sixth series, during March and June, 2(1,000 lbs. milk, test- 
 ing an average of :"..84 per cent, fat, was equally divided : and one- 
 half was .separated at al.out»0 dejirees and the other half was pasteur- 
 ized at KiO degrees. The per cent, of acidity m the milk when re- 
 ceived was .15.i. The acidity of the unpasteurized cream at the time 
 of adding the culture was .154, and that of the pasteurized cream was 
 131 Both lots had about the same acidity at the time ot churning, 
 viz 5 per cent. The pertenta<ies of fat in the cream were 30 per cent 
 in both cases. Tlie fat in the skim-milk in both cases was less than 
 one-tenth of a per cent., and the buttermilk averaged .15 per cent. tat. 
 Both lots were ripened at the same temperature (04 degrees) and wer.' 
 
9 
 
 churned at the same temperature (47 degrees). The average time of 
 chuTMUg was 41 minutes for the unpasteurized cream andl? minutes 
 loi the pasteurized cream. 
 
 Scoring of Series VI. ' 
 
 Comparison of butter made from unpasteurized milk, with butter made 
 from milk pasteurized at 160°. 
 
 No. cif 
 Samplei. 
 
 Kind of Butter. 
 
 no 
 
 110 
 
 /3 
 13 
 
 { 
 
 (JnpMtrurizer) 
 
 Pasteurized at 160 degreei ....'.'.'. 
 
 UnpaHtxiirized, March . 
 Pasteurized at 160 degrees March 
 
 Unpasteurized, June 
 
 Pasteurized at 160 degrees, June! 
 
 i 
 
 6 
 
 1^ 
 
 1. 
 
 h 
 
 Average 
 Max. 
 
 < 
 
 > 
 
 < 
 
 > 
 < 
 
 38 
 
 24,8 
 
 14 4 
 
 92. VO 
 
 3».4 
 
 25 
 
 14.3 
 
 9.S 65 
 
 :«.;< 
 
 24.3 
 
 M.3 
 
 87 
 
 ;«.H 
 
 35 
 
 14.2 
 
 '.to 
 
 40 
 
 25 
 
 14 4 
 
 94.4 
 
 41 
 
 35 
 
 14.2 
 
 96.2 
 
 The keeping quality of boxed butter from milk pa-steuiized at different 
 
 temperatures. 
 
 T>ateof 
 Making. 
 
 Temperature. 
 
 July 5 
 
 Aug. 5 . . . . 
 Apr 24.... 
 May 27.... 
 
 July 5 
 
 Aug. 5 . . . . 
 Apr 24.... 
 May 27.... 
 
 July 5 
 
 Aug. 6 
 
 Anr. 24.... 
 M«y27. .. 
 July fi 
 
 Aug. 6 
 
 May 27 
 
 Unpastnurized 
 
 14 
 
 Pasteurized, 140 decrees 
 140 
 140 
 140 
 160 
 160 
 160 
 160 
 185 
 
 185 " 
 185 
 185 
 195 
 
 Scor«H for flavor at end of 
 14 days. I 60 d 
 
 42 
 43 
 42 
 43 
 41 
 43 
 42 
 4S 
 41 
 42 
 43 
 42 
 42 
 43 
 43 
 
 36 
 39 
 32 
 42 
 34 
 38 
 37 
 41 
 37 
 39 
 88 
 41 
 41 
 40 
 41 
 
 1 125 days. 
 
 j 164 days. 
 
 .36 
 
 
 
 
 42 
 36 
 
 40 
 
 
 r"v • 
 
 ' 36 
 
 "'39'" 
 
 
 41 
 40 
 
 41 
 
 
 h ' i| 
 
 U 
 
 39 
 
 41 
 
10 
 
 Keeping Quality of the 2/tt«cr.— Butter for cold storage and for 
 export must possess teep 1*1.9 quality, a point which is usually over- 
 looked in judging butter. If we are to compete in the British markets, 
 Canadian butter must overcome the prejudice which exists in England, 
 
 that it will not " keep. ' „ . j- i ^u * 
 
 Our experiments during the past six years all indicate that pas- 
 teurization improves the flavor and keeping quality of butter made 
 from winter milk In summer, when conditions are more favorable 
 for the making of fine-flavored butter, there is not so much difference 
 in the flavor of the butter when first made, whether pasteurized or 
 not However, when samples are kept for some time— 60 to 160 days- 
 there is quite a marked difference in favor of the butter made trom 
 pasteurized milk. Our experiments for the past two years also show 
 that the higher temperature of 185° is more favorable m the produc- 
 tion of " keeping quality " than the lower temperatures of 140 to 100 . 
 Bacteriological Data.— The culture media used were ordinary lac- 
 tose agar and whey gelatine. Usually 4 plates from each sample were 
 poured, two of lactose agar and two with whey gelatine. Ihe whey 
 gelatine gave very satisfactory results. It was made from whey, boiled 
 and filtered, to which was added h per cent, of peptone. ^ per cent, ot 
 Heyden's Nutriment (Niihrstcff Heyden), and 10 to 12 per cent of 
 
 ^^ * tS acrar plat-s were kept at 20 to 30° C. (83 to 86' F.), and the 
 gelatine pktes at 20 to 21" 0. (6S to 70'> F.). Of the two kinds of 
 media whey gelatin.- was preferable, as the colonies of the lactic acid 
 bacteria were larger: and the spreading surface colonies on the agar 
 plates made counting rather difficult. But little numerical difference 
 between the plates made from the different media, was noticed. 
 
 The samples of unpasteurized milk were taken directly trom the 
 receiving vats, after the milk from all the different patrons was 
 
 thoroughly mixed. ^ . i xv. 
 
 The temperature of the pasteurized milk was taken by a ther- 
 mometer inserted close to the outlet oi the milk from the pasteurizer ; 
 and the^e samples were taken from the outflowing milk in large steri- 
 lized test-tubes, and brought to the laboratory, where the analyses were 
 made at once. 
 
 f)il„fion.— The sample was thoroughly shaken, and i c. c. was 
 added to 10 c. c. of sterilized water, and i c. c. of this mixture again 
 added to 10 c. c. water, and a small fraction of this was added to the 
 culture medium, and plates poured. By means of this dilution, the 
 colonies were not too crowded on the plates ; so they could be easily 
 counted. With the pasteurized .sample no dilution with sterihzed 
 water was made, about 1-20 to 1-30 of a c. c. of the pasteurized milk 
 being directly added to the culture medium. 
 
 ;A 
 
11 
 
 Jiesults of Continuum Pu^horizaflo,, of At ilk at UO-IAO F 
 Thirteen tests, percentage of bacteria killed, itr).42. 
 
 Date. 
 
 April 10 
 
 << 
 
 12 
 
 11 
 
 15 ■■ 
 
 May 
 
 1 
 
 4 
 
 11 
 
 18 
 
 It 
 
 21 ■■■ 
 
 27 
 
 »i 
 
 29 ■ 
 
 June 
 
 3 
 
 »« 
 
 6 . ... 
 
 (t 
 Aug. 
 
 8 
 
 6 
 
 
 
 UnpaRteurizad. i PMtrurJMd. 
 
 Average No. of 
 Kerms per c. c. 
 
 8,090.000 
 
 ■■<.7.S6,000 
 
 3,7a5 00O 
 
 8,73fi.00O 
 
 13,400 000 
 
 14,510,000 
 
 S«,8S0,000 
 
 16,260,000 
 
 17,()00,tlOO 
 
 15 670.000 
 
 I'>,".'3.000 
 
 22 340 000 
 
 61,(t0t>,000 
 
 Average No. of 
 gerniB per c.c. 
 
 243.600 
 2.(6.000 
 218,600 
 567.000 
 367,000 
 887.000 
 800.000 
 667,000 
 a'JO.OOO 
 7L>0,000 
 672,000 
 812,000 
 1,400,000 
 
 R''.svlt>^ ofGontiniiom Pa.^trariz',t;,„i of Milk <>t WO-Pjr/ F 
 Twenty? tests, percentajre of hucteria killerl. 99.9,5. 
 
 Date. 
 
 PaateurizingI '''«•«'!*'•»• 
 tempera- l'"!* "' """' Aciditv 
 tore I ''^fo'e PM- |'*«""'y- 
 I teuri/.ing. 
 
 UDpa§teurized. Paateurize.l. 
 
 Mar 
 
 2J» 
 
 April 1 
 
 • « 
 
 3 
 
 <l 
 
 6 
 
 u 
 
 8 
 
 t 
 
 10 
 
 II 
 
 17 
 
 11 
 
 19 
 
 (« 
 
 29 
 
 May 
 
 1 
 
 
 15 
 
 (1 
 
 16 
 
 t. 
 
 18 
 
 (1 
 
 23 
 
 II 
 
 27 
 
 11 
 
 28 
 
 June 
 
 8 
 
 11 
 
 5 
 
 II 
 
 7 
 
 Aug. 
 
 5 
 
 Average germa Average germi 
 P^f C.C. J per c.c. 
 
 160 
 
 53 
 
 .15 
 
 160 
 
 46 
 
 .16 
 
 164 
 
 52 
 
 .15 
 
 160 
 
 54 
 
 .16 
 
 160 
 
 ra 
 
 .15 
 
 160 
 
 54 
 
 .15 
 
 160 
 
 66 
 
 .19 
 
 160 
 
 46 
 
 .17 
 
 165 
 
 60 
 
 .21 
 
 160 
 
 58 
 
 .15 
 
 165 
 
 60 
 
 .19 
 
 IfiO 
 
 60 
 
 .18 
 
 160 
 
 61 
 
 .19 
 
 160 
 
 61 
 
 .17 
 
 IKO 
 
 .58 
 
 .17 
 
 160 
 
 62 
 
 .16 
 
 160 
 
 5S 
 
 .16 
 
 160 
 
 60 
 
 
 162 
 
 68 
 
 .16 
 
 165 
 
 
 
 507,600 
 
 1,402,100 
 
 288,000 
 
 2,784,000 
 
 7,040,000 
 
 8,090,000 
 
 9,090,000 
 
 1. 820.000 
 
 25,100.000 
 
 8,7.W,0()0 
 
 4.060,000 
 
 1,511,000 
 
 14.510,000 
 
 13,276,000 
 
 16,2.50.000 
 
 23,400 000 
 
 15,670,000 
 
 16,274,000 
 
 31.113,000 
 
 51,900,000 
 
 510 
 8,9.50 
 610 
 410 
 9,026 
 650 
 2,800 
 9.<,800 
 ll,4l'.J 
 -'.■t,2f0 
 10,700 
 16,800 
 13,000 
 7,400 
 12,000 
 6,300 
 4,700 
 11,700 
 8,370 
 10,200 
 
 It 1 
 ft \ 
 
 
 !•? 
 
 
12 
 
 Resvlts of ContinuouB Pa.teurimtinn of Milk at ISo' F. (85' C.) 
 Fourteen tests, percentage of bacteria killed. 99.99953. 
 
 iHte. 
 
 PMteariziog 
 
 teiuper«- 
 
 ture. 
 
 Tempera- 
 tars of milk 
 bvfore P»«- 
 
 teurizing. 
 
 April 
 
 M»y 
 
 Jane 
 Aug. 
 
 19 . 
 
 17 . 
 33 . 
 29 . 
 
 4 . 
 IB 
 23 
 2S 
 37 
 98 
 29 
 30 
 
 4 
 
 5 
 
 185'F. 
 
 186 
 
 186 
 
 186 
 
 1H6 
 
 186 
 
 186 
 
 185 
 
 185 
 
 186 
 
 18o 
 
 186 
 
 186 
 
 186 
 
 Acidity. 
 
 UnpMtaarized. I PMtearized 
 
 63 
 
 .16 
 
 6A 
 
 .19 
 
 60 
 
 .19 
 
 60 
 
 .21 
 
 58 
 
 .17 
 
 60 
 
 .19 
 
 62 
 
 .17 
 
 61 
 
 .17 
 
 68 
 
 .17 
 
 62 
 
 .16 
 
 60 
 
 .17 
 
 61 
 
 .16 
 
 60 
 
 .16 
 
 Average No. of 
 germ* per e, o. 
 
 3.736,000 
 
 9.090,000 
 
 2,964,000 
 
 26,100,000 
 
 18,400,000 
 
 4.060,000 
 
 18,500,000 
 
 18,276,000 
 
 16,350,000 
 
 23,400,000 
 
 17,000,000 
 
 14,600,000 
 
 23,110,000 
 
 61,900,000 
 
 I 
 
 Average No. of 
 germs per c. c. 
 
 80 
 
 144 
 
 44 
 
 30 
 
 33 
 
 80 
 
 113 
 
 60 
 
 66 
 
 300 
 
 34 
 
 90 
 
 117 
 
 113 
 
 Eight tesb, percentage o( bacterii. killed, 90.99968. 
 
 Date. 
 
 Paateurizing 
 
 tempera' 
 
 tare. 
 
 April 
 If 
 
 It 
 May 
 
 15 . 
 
 19 , 
 
 22 
 
 16 
 
 21 
 
 22 
 
 27 
 
 80 
 
 200 
 195 
 196-200 
 195 
 190 
 195 
 195 
 19b 
 
 Tempera- 
 
 
 tare of milk 
 
 \cidity 
 
 before Pas- 
 
 teurizing. 
 
 
 54 
 
 .18 
 
 46 
 
 .17 
 
 an 
 
 .12 
 
 60 
 
 .18 
 
 til 
 
 .17 
 
 62 
 
 .17 
 
 58 
 
 .17 
 
 61 
 
 .16 
 
 Unpaiteurized. 
 
 Average No. of 
 germii per c. c. 
 
 Pasteurized. 
 
 Average No. of 
 germs per c. c. 
 
 3,705,000 
 1,820,000 
 2,964,000 
 1,571,000 
 38,.*<80,000 
 18,500,000 
 16,250,000 
 14,500,000 
 
 16 
 77 
 It; 
 87 
 96 
 Mi 
 
 
 
13 
 
 The Bacteriological Results.— The milk used in the variouH paa- 
 teurizing experunents may bo sjvid to have been of goal quality fn 
 only one or two instances did the acidity exceed 0.2 per cent of lactic 
 acid, an arbitrary standard proposed bv Russell, as it was shown bv 
 that experimenter that milk having a low percenta^'e of acidity was 
 as a rule freest from spore protluciug bacteria; ami the stamlard 
 mentioned (0.2 per cent.) was found to give good results in practice 
 A comparison of the acidity with the number of bacteria per c c' 
 m any ot the tables will show, however, thut nodeHnite relation exists 
 between the two ; as, for instance, the bacterial content in one sample 
 was over as millions, and in another two millions, and yet the acidity 
 in both these owes was the same, viz., 0. 17 per cent. . he explanation 
 ot this tact IS that large numbers of Iwcteria were present which either 
 produced no acid or else but a slight amount. Bacteria belon-ring to 
 the colon group were often present in large numbers : and the.se 
 whilst producing acid, do so to a far less extent tlian the true lactic 
 acid bacteria. 
 
 The effect of continuous pasteurization at UO degrees is undoubt- 
 edly etficient.as 96.42 percent, of the bacteria an- killed ; but we must 
 remember that the effect of this temperature is just on the border 
 between efficiency and non-effieiency. In practice there is apt to be a 
 lowering of the temi)erat\ire from time to time, periiaps due to les.sen- 
 ed steam pressure, too great an inflow of milk, or other causes • and 
 when this happens, there is a great loss of efficiency, and the number 
 of bacteria which escape destruntion is greatly increased 
 
 Unfortunately, too, the desirable lactic acid bacteria necessary for 
 buttermaking are the Hrst to succumb ; and the undesirable bacteria 
 hardier and more resistant to adverse influences, are either not affected 
 or only to a flight degree by tliis temperature ; and if left, even in 
 moderate numbers, they rapidly increase when the cream is placed in 
 the ripening vat, and may give rise to " of! flavors." A glance at the 
 accompanying diagram (I. t will show the large number of bacteria 
 which remain living after continuous pasteurization at 140 degrees— 
 too many which are as a rule undesirable for the best results. 
 
 At 185 degrees, however, the results are ranch better (diagram 
 III.), probably all bacteria except those forming spores being killed. 
 We must also remember that this temperature has been shown by 
 Trof. Bang of Copenhagen to be sufficient to kill the ti cle bacillus 
 (hacdlus tuberculofiu) thus removing a source of dang o man and 
 animals. 
 
L PMtoarued fl.t 14 0* F. 
 
 IV76 Batteria per cUJi 
 
 o ceni.m'trc life drop*) 
 
 n. pMteuriied M IfcO' 
 321 BACteria^ per civcent 
 
 7. Bacteria, per tu. cen- 
 
 E pAStearised ftt 195* P 
 I B&cfftriam per cu. cent. 
 
 [14] 
 
15 
 
 Slmmahy. 
 
 paHteuri/ed. Tho in.lk use.l in thoHo experiments was lar.relv furnished 
 by patronn who had but oniinarv facilities for takin.' care of it ,, 
 
 n..lk^eoa«nIat.nK when heated, if it clntains ,„ore thai 2 pe"; cent, of 
 
 ;<• It was noticed that the lots heated fro.., 18.-, .Je-M-e.-s to l'>o 
 decrees produced ...ore foa... than those heated to the Im er te mer 
 atmes of 140 .le^reeH to l.iO ,le«.ee.s. This was ..1 , ot^^ ^.ble i7u J 
 saiuples heated to 19.5 dejjrees. At 18.5 .le«rees. the foam Zns . t 
 suthc.ent to cause much trouble in I.andlinL' 
 
 4. Hy co<ilin;; the Hki.n-..nlk with water to a te...pe,-ature of aln.ut 
 6o dejrrees .......ed.ately afte.- it co.,.es fro.., the sepamt r e wm 
 
 •>. The use of 10 to l.'. pe.- cent, of culture in tho i.a-teu.i^e.J 
 cream enabled us to ripen the crca... without any diffieulty ' The c-i 
 ture used was a lactic acid bacillus. ^ ^ *-"' 
 
 6. Pasteuri/atio.i of milk at IS.j d.'<rrees and the im,. nf « ,..,..„ 
 culture s the best .nethod of securing unif/Sy kl in." , .^ i^y' " J 
 the mild flavor requisite for export butter. i., |uani>,aml 
 
 milk'»;oJ-'lVr^'"\S-''7' '^'"'''' '''"" I""^'*^"^ >» t''« ''"tter ...ale f.-o,,, 
 milk heated from 18.-, decrees to 19.5 de^-rees. usually disappeared at 
 the end ot about two weeks. In one or tv.-o lots, heate.! to U^h^L^ 
 the cooked flavor remained for some ti,..e. There is appare, % no 
 dannrerot cooked flavors on butte,' made fro,.. ...ilk pasteurized at iSs 
 
 were kept m the stable, were very i.n.le.sirable. Many putrefactive 
 and fe^al bactcia were present, hence the necessity of keepino-t he 
 stable walls and rafters well cleaned. A jjootl coit of whitewash 
 increases the amount of li.ht, and ,dves a General clean etfect t Se 
 
 9. The avera^re number of bacteria per c.c (KJ drops) found in 
 To 8ir T;-''.^ ''' 140 decrees F. wa.s 631,040, at l.iO .ij.ree.s T wis 
 l.-,S48, at 18.> dej/rees F. was 81, and at 195 de-rees F. was 4() (See 
 diagrams). " ^ 
 
 ill 
 
1 
 
 The tlleet of Iht etmtinMuui patttitriMtion of milk 
 at !!/>' <« ^■^''' ''• 
 The white wiuare rt^prfteoti the b«cterj»>c»n- 
 tent of r»w n.ilk-»ver«t{e of thirteen dayn in 
 April. M«y. .Iuo« »nd Augnrt. The bl»ok 
 •mce repreient. the b»ot«ri.l content of the 
 ■•me wmple* after oontlnuont pMt«uriz»tlon at 
 140" to 14<i« F. 
 
 TKt tfttet of the eimtinuovt pa$teuriiation of mtik 
 at It'" (.. 105" F.(71''-74'' O ). 
 The white wniare repreMnU the bacterial con- 
 tont of raw uiiik -average of twenty day* in 
 March. April. May. June and AuKuit. Th« 
 black »pace re|>re«enU the bacterial content ol 
 the iame •ainile* after continuou* pMteurwa- 
 tiun at IWlt.i" F. 
 
 The etfeet of the con/''""""* rmtt^irization of milk 
 utlSSOFASS^C). 
 The white Kiuarr reprcaenti the bacterial con- 
 tent of raw milk-av«r.Ke of fourteen day* in 
 April, M«y. Ju..*- »nd Augnrt. The black Mt 
 lepresentu the b.ct>Tial content of the lame 
 ■ample after pasteurization at 185" F. 
 
 The f fleet ot the continuout parteuri:ation of b»W| 
 at 195-> to mf (F. dV^ff O.) 
 The white jquare rep reents the bacUrial cop-l 
 tent of raw milk-average of ewht dayi i»l 
 April and May. The black spot representJ tbei 
 bacterial content of the lame MmPjea »"«' '=<'"f 
 tinuouB paateurization at 190" to 200" F. 
 
 [16 I 
 
 jaiaKi * ii