/ « w,.. I ' ‘^4 J r: \ I /• ■ ■ A I ✓ \ ( > < ( 1 ' I i r /' ■f , ^•J «i0h s ' -S' / » > y « > A COMPARISON OF THE SUGGESTED METH- ODS OF BACTERIAL ANALYSIS USED IN GRADING MARKET MILK BY THEODOR MARTIN IIANFT AND JAMES ROLLAN HUDSON THESIS FOR THE DEGREE OF BACHELOR OF SCIENCE IN AGRICULTURE COLLEGE OF AGRICULTURE UNIVERSITY OF ILLINOIS 1922 Or. • «, ‘i» ■ "li' •» ■" :; ^m ' ^ i_ • ■ : ■■" ^ ‘ •■'»,^. .>«• •. "■ ■•' '. ■'I,?.'' w I I - ‘ A • —J~t ^’ XV 1 - •*•_.. yt t'» V. y^v ■, n '■ ■'> ■ yxtm '.I Iri i'47',H ;v2f ■ ,*^/ «M ^ , . f • Vn .*7 E||||' : ••■? '*r. 1^ . f 'J (*>' t. ' i-* < 'Ji ^fA'- f ^ • ^ I • > <' *~u V’ ;^-S . ) . \V ,. ivf, '^' . hiM f'"-' ■ <>. / . ,.^v u' • '. .V. ' vl - • ' ' ' %Bi' ^ ^vv v ^ ‘O ' •' .' c^ShT' •* /*J :»• JS-> •'. ,* .-Ar'.Wf V • , O , A 'A ' ' ■ nnoii iSiTJjw ■>* ‘ . ■■ (5g 1=;^ K-a PTh...-.'','? ;'i#":;'j UNIVERSITY OF ILLINOIS jy. . .S 1 9 ?.S . . . THIS IS TO CERTIFY THAT THE THESIS PREPARED UNDER MY SUPERVISION BY .T.hs.P.d.Qr. . I'fe r t.i.n. . .Ifenf t„ and_ James Rc 1 Ian _ s on ENTITLED A.. .C.pi»P:^r.Us.P.n..pf....tLe.. Sugg.es ted _ Me thod^^^ Ab& ly.8 iP . . .Va .P.d . . .In. .Grading . .f-ferPe .t . ,M i Ik IS APPROVED BY ME AS FULFILLING THIS PART OF THE REQUIREMENTS FOR THE DEGREE OF J^S.B0.l9.r...QL..Sci.snR)?...ln...Dai^^^ HEAD OF DEPARTMENT OF r&ir.y...HuaT:aniry. MV - p , I ■■ . r - ,. u , eionijj ! 10 YTJeaavrutu ¥ Vi 4 . '« n 1 ^. ,. ■ •. rui '.iM r;v»'{ iiHT 1/ HI y’-iiTvi.w:>or ai diHT ,/ % M i\. j ip tis'sfvw'3 fi-iltiTKaa ■ ' i' - ■; 1 “'^ ■Ilf ; ■■" * • iflj !(;• is 'll. ■ ■)' ) I '/•< i«i rwT.i iiiu./-: 'ne /-j ojvoa’Hi'tAat ' m M ■o . ii .-) 'jsaaan :1 ' At ; 9^ \ 'V ' I I. ' • >M I 1 3U r) .1' V ^ < \ t \" . . V » ' - r.,rrfr •■ ' . •'■• \ . ,1 I N . / j*ir . L lO 'i '/iS>A r>fk^m HO Y/Aj^'h •'*,0 ' ' ■i , .* ACiaiOV/LEDGMSHT . The authors wish to take this opportunity to express theiK appreciation for the suggestions and supervisions they have received from Dr, M. J. Prucha, Dr. H. A. Ruehe, Dr. P. W. Tanner, and Mr. B. A. Stiritz. » . r ii t Digitized by the Internet Archive in 2015 i, https://archive.org/detaiis/comparisonofsuggOOhanf TABLE OE COITTEITTS. Bac« I. Introduc1;ion._2, II. Object. 2. Ill .Method of Procedure. 3. A. Method of Sampling. 3. B. Sediment. 3. C. Plate Method, 3. 1. Dilutions. 3. 2. Plating. 4. 3 . Agar . 4. 4. Incuhation. 4. 5. Counting. 4. D. Erost’s Microscopic Plate Method. 5. 1. Preparation of Glass Slides. 5. 2. Preparation of Plates. 5. 3. Incuhation. 5. 4. Preparation of Plates for Counting. 5. 5. Counting. 6. E. Breed Microscopic Method. 6. 1. Preparation of Smears. 6. 2. Counting. 7. E. Methylene-hlue Deduction Test. 7. G. Acidity Test. 8. IV.Experimental . 9. Table I. 10 . Table II §lass "A”. 17. Table III Class ”A” . 19. Table IV Class ”A" . 21. Table V Class ”A" . 23G -L « I.IIITRODUC'TIOII. Tliere is a grov/ing tendency among milk dealers to purcliase ; milk on a grade "basis, paying a "bonus for high grade milk. This [ is an advisa"ble practice in that it tends to stimulate the pro- duction of better milk and to enable the dealer to control the quality of his supply. That the bacterial analysis of milk is of great value in 1 the dairy industry has been established beyond all doubt. It not only gives some idea as to the past history of the milk but also as to its future with reference to keeping quality, before a dealer can control the quality of a milk supply he must Imov/ the bacterial content of the m.ilk from each patron. It is also valu- able to have some loiov/ledge of the sanitary conditions under v/hich the milk has been produced. This knov;ledge can be quickly and easily obtained by the use of the sediment and acidity tests. The sediment test shows the amount of visible dirt in the m.ilk, Y/hich 2 operates as an incentive for the farmer to produce cleaner milk. The acidity test serves as an index as to the care under which the 7 milk has been produced and oi its subsequent handling. In making the bacterial analyses of milk, several different methods have been suggested, namely: Standard Plate I'ethod, krost "Little" Plate liethod, Sreed Method, and Methylene -blue Reduction Test. These methods were studied and compared in this investigat- ion together vrith methods of analysis of keeping qualities such as Sediment and Acidity tests. This investigation was carried at the University of Illinois during the fall of 1921 and the samples worked with were taken from the patrons of the University creai'iery. -'t -r ■ '? i / . J *■'. v> ;. :>h .-'XSi :3r!f liiy';-*^ - ,1 . .J ». f, I ikl; r /,-■!/ ■ «(■ M . .'•:VV 'ut -ir:iht::3_^ i/t. ,%iv-fl. . I j ■ .’lii '. X >i 3 f JTi XO' :• 541. , -•- ( * -xi..v '.y ' is» ■ ri i • ^ .. I • t . -■ &ftt ‘V ■' . ,^ ■ i‘ 'fiiii' • a*’.; 4 JO <(*'S >* f *4 L» • t < J ■ iiV:X J >.< ?v fif ’ ■ K.' ■' :r' - • V 1 >. . V-. ri_ ■_'^. , %jpv 4 r'l , /*-*!• 4 ’.tf ■•' •»:- iLj* (■ ;, J ij' a- / ' ■; .: OJ" . I'v.’ ' ■ . . 3 f ■iS' W% ■: Xk' f I ■ - /*. ' . ... ^ 4. ^ . 4 '^ fj,vaf’ ?k‘- js), ' ■ iist .,' . V,. ■ '•^.- JS'C* • \ K-f. i , ' ‘ ' j' ' -X' ‘ ■' ■.' ' V'^ : ■; .SI • ' ;• '■ ‘ . ■ ••;*'/ 4 >^>/’?fl , ,V-' ' ’ ’ 'V-, »,f It, ' : . -,p'fr‘ idikyJi^^ ' '} ..i' iv J ?».' ' '< . .. r«!M*iar* ■ ;■ y >7 ■ ' .vT' . fW . M 1 II. OBJECT. Each method of milli analysis that hears on the bacterial content and the heeping quality of milh has value in a system of grading milk. It was the aim of the authors of this study to compare the Microscopic methods of Erost and Breed and the Methyl- ene -blue Reduction test with the standard Elate method and to study the correlation, if any, between the germ content of the sample of milk and its acidity and sediment. Also to study the relation and adaptability of the above tests in a system of grad- ing market milk. \ If 5 III. KETHOD OF PROCEDimE. A. He oho d of sampling. 100 cc. of raw milk v;ere taken directly from the cans as they came into the receiving room, by means of a sterile 100 cc. pipet'oe and placed into sterile ground glass stoppered bottles of 250 cc. capacity. In most cases the plating was done immediately, other- wise the samples were keep in the ice chest until they could be plated. B. Sediment. Immediately after the sample for bacterial analysis had been •uaken the milk v;as thoroughly stirred and one pint of it taken, by means of a dipper, for a sediment test. I'he amount of sediment was determined by means of a wizard sediment tester, by forcing the milk through a white cotton disc one inch in diameter which retained all the insoluble sediment on the disc. These discs were mounted on cards as shov/n in Plates I-IV, together with the patron number and the labors.tory number of the sample. The amount of sech iment on each disc was estimated comparison v/ith a standard chart made by v/eighing accurately varying amounts of dirt and de- positing them on similar discs by passing one pint of milk con- taining this dirt through the discs. C. Plate Method. 1. Dilutions. Dilutions of 1-100 and 1-1000 were used in all cases except in a few instances where the samples were Imown to be of high bacterial content in v/hich case higher dilutions were employed. Dilutions were naade by adding one cc. of the thoroughly shak- en sample to 99 cc. of sterile v/ater; of this dilution a one cc. portion was added to 9 cc. of sterile water. The dilution ¥iraters > . I y' ^u ’i .* QT- ■»*i.A '' '■' * ^ >•> 'f,'.!' ^V"\^JffM, fr* ^ii'''’:' !. ^:it''V ■ '• ;1 i.:«i fr* f.' ,.n''.-:'*_ ".ttv ■ ' ' - '* f vT . fiVi|i|j 1 /j/ j vMi ■ I ^|f * £r*iP^»»T» t:- >f¥^ ■ •J#--. *.... ■1 „P-‘*jSK •'‘•'"■••■Ag ^ ■-. 'J » . ♦ •» ■ 1 ■1-i* ;7j ! lit 'S« • ■•- •- j:i r •. . t.i iT'-?..!!: 3/u' . si ' lofri. Tsti- tl)r t .. .:■ ^ I O'j A:.. ■ji ■■ ■ i- -■ - ' '* i . ^ '' / L * 'l- C' '.jw ■ ■if»-'''^!l»'>^^ "»S7S /fy ■ ' »< if V''» ' ■ •• ^^ A ... 4 ■ *- ' . ) ' •■'.V '■ ,.' K:.: ' ,i i v'f T,?: ^ .*i:;.i 'w> ■ i,V__ -r. jit^y . ?*r '; 35*# t ft ?? ■'•• • ' ) *,f ■- ‘‘" -:o r . i. ■ •:!: : J ff ■ '‘'' • :■ ■ .V *' f '^v ..• V VH ■•; ■»■«:'«&• t 26 j^ i ■' t ■»# >•- ,y 1 ■'■ •'• **>';v . 'v^‘ .. 4^^c! .. 'V' wf • . \ : i ‘''-*i^’ t. , . . ^ 'i / t'l ‘A' 4 were sterilized in flasks containing 99cc. of distilled water and in test tubes containing 9 cc. of distilled v/ater in the auto clave at fifteen pounds pressure for one hour. The flasks and ;; tubes were stoppered v/ith cotton plug’s and a fresh supply was made, just previous to each set of saroples run. Sterile straight sided : pipettes, graduated to deliver one cc. were used to measure out the portions of milk or dilution and each pipette was used but once before it was re-sterilized. 2. Plating. Phe dilutions v/ere plated in duplicate and for each plate one cc. of the dilution was measured into a petri dish by means of a sterile one cc. pipette. Then sufficient agar (about 10 cc.) was added to cover the bottom of the dish. The agar v;as poured at a temperature of 45 degrees U. so that it would flow, and yet not be so hot as to kill an^^ of the organisms. The dish was moved in a rotary motion so as to mix the agar and sample thoroughly. o . JLgar . In this work the ordinary nutritive agar was used. This med- ium was made up as follows; 10 grams of "Difco” standardized bactO’ peptone and 5 grams of Liebigs beef extract in one liter of water. 4. Incubation. The plates were incubated at 37. 5*^0. for forty-eight hours in a well ventilated incubator. 5. Counting. In coimting, those plates containing from 30- to 300 colonies Y/ere selected and the count multiplied by the dilution was report- ed as the final count. If there were no plates v/ithin these limits, the one nearest to 500 was counted. On miaten colonies ir cxnAnp. of 3QQ-P..Q.31- I r r- T i( ' W •I -.i.j.-“. 'i : » i» s. ; ' ’-' *'i .. • r«,VK>J i *%f’t I £ ■ ' T ^ '-''^VaLh /{ . "1C' "'I r.-ne _y ■H. - .’ >n Vjjf. • iJ> 0^ ry 5T*4<> w ''Vt^--'®' ■I'- •• V -t. ':m<^ HtfXp «• ,1* I -•^’ V fi ,- .^,-03 --ir.i’^' t •J .* i. V •■ *^ , ' ■ I ■' .'/J.Hl?/ ■ ■Jl:\ .>'■ r’^ *,; ^ •;. ./iX ' ^ •?? .ffV\r'f-;’v -te;' '-‘iu^ ■ *uy- ■: \ ,. L- ■' y yv-"' ,,^W«»i»<‘ si/ V . ^iww, j sws't *r. 7 f* ^.’ ■\^ "’1 >w ; ^ , ' ft - •■ ' .ri ' ■ •'/ , T 4 ' (\.» f .... i ..« • ■^9. r '#l^.^^*'iC4 ,1 -U^ vA' ‘ .. n ■fiii j> ■ ' t !•' ^ ,^- , . V •*T U . . V- A-^* ^ '/,% ■ ' ^. , . i .. . . V.^lpJa: W'M .* 4 _. ' * ar-js: .-^t* h,rMj \ <■ ••'' ' R >■■ ' ; , 5 plate, part of the plaice was counted and the number estimated. Count inc v/as done with a lens and all reco{;nizahle colonies were included, \7herever possible both plates of each dilution were counted and the avere.ge reported as the final count. 1). Frost's Microscopic Plate Method. 1. Preparation of glass slides. The plates were made on the ordinary microscopic glass slides (2.5 X 7.5 cm.). The slides v/ere carefully cleaned and then ruJ.ecl with a grease pencil so that a 4 sq. cm. area v/as inclosed with a grease line. Two of these area v/ere marhed off on each slide by means of a cardboard frame. 2. Preparation of the plates. The slides were sterilized by passing then throug'h a flame and then 0.05(l/20)cc. of the sample of mhlh placed on it with an accurately calibrated pipette. An equal amount of sterile nutri- ent liquified agar at 46° C. was added and the two drops thorough- ly mixed by means of a sterile loop and carefully spread over the area marhed off. The agar was allowed to set firmly by placing it on a level surface under cover for a few mnnutes. This made a little plate cultured containing 0.05 cc. of milk. Samples were plated in duplicate. 3. Incubation. Incubation v/as accomplished by placing the little plates in an incubator with a layer of v/ater in the bottom to maintain a saturated atmosphere. They v/ere held at 37.5° 0. for eight hours. 4. Preparation of plates for counting. After eight hours of incubation the plates were carefully dried, fixed by passing through a flame and treated in a lOp sol- ution of acetic acid. Upon drying, the plates v/ere stained in a I L . ■ I » 'r9fr>/WV- /. £i *, f ^ I ^ ... *• } . » I ^ ' .V ■{: >):sh f' <- !.'-•- 1 wr.^ . . ^ > I ^.-z r i •r - - ^ )♦ i-' »V •- 1 , / . . . .' ■» “ 1 >r. “ ■ • ' ■i . ■ *** '^ird ' . ' -..pi » ..Titim ■«?» ■ l^- Jffr^ ' V ' I?’ ✓ rt* ■ '■"• V..;’ ’ •■ ’ii'U!’ r ■ L "’ ' . «' _!k •' I I w' • ^ - '..;S| * e% :-'tM V'- iir: I ' 'ill .■W*. I I.; .r i f >/ 1 “/ 7 * T>^ w AJ i^y i* lA .'V •.'Si?/ ; ... - '.V '.‘T ‘i-r - *!■»«? '"IlLJiHWi ,., ,.t ..1...^^ f .'su;. I lA. n ' u LoeJflers Methylene -blue solution (1-4-J for a few minutes, and decolorized in a 95';i alcoholic solution, until the hacVgrounds were a pale blue and the colonies stood out prominently. 5. Counting. I?or the purpose of counting the colonies, the slides v;ere exam.ined under the microscope with the low pov/er dry lens. This revealed colonies of considerable size stained a dark blue in a light blue field. fhe microscope was standardized by means of a stage micro- meter and so adjusted that each microscopic field covered an area of 1/500 sq. cm.. This gave a microscopic factor of 4000, that is: the average count per field was multiplied by 4000 to give the final count. This is true because there v^ere 200 microscopic fields in each 4 sq. cm. area or the area covered by the plate. Each plate contained 0.05 cc. of milk; therefore, each field con- tained 1/4000 cc. of milk. Duplicate plates were made of each sample and ten fields of each plate counted and the average taken for the final count. E. Breed Microscopic Method. 1. Preparation of Smears. l/lOO cc. of the sai^ple of milk was deposited upon a glass slide by means of an accurately graduated pipette. By the use of a sterile platinum needle this drop of milk was spread over an area of 1 sq. cm.. This v/as accomplished by placing the slide on a glass coimting plate which was ruled into one sq. cm. areas. After uniformily spreading, the preparation was dried in a w v;arm place upon a level surface. After dryin^ the slides v/ere dipped in Xylol for one minute, then drained and the slides dried. They were then immersed in 90^^ alcohol and then transferred to a Ir , - ■ » , le/; r vr.j^T t I , ~. •} .'J ■• J < '■ • h ,. . . ■'•'ii: - £ ' ' t V ■ ■ -■ ♦ . ' » * .r _Ar ■ ' • « I . U, •'>5- I «, i t i- 'k* ^ ■■ "ij-: •* ic.h ’ : U' • r)ji'.:Si ip.'.,. ^ at'K" < :--.>V 7 i t) ^ m U f l .•* * c ■ ,ii6 iHMtIEVrt :% . ' i- ' t^'" 'v> X tt V- ..'■''i,':^iE' ’ ' ff • ,A_. tr ^ ’*1 1 . ', >*,.•:. •*' • ' .; .'.‘.N, - V- O WT-.„ V > ‘ ' ' '■ . 4 ■ ' ■•* if': ■ , ■ v.:",, '.m' » ■ v;fi \^t' ''/Vi';- •■« - «t . " ■ ■ ' 7'i"' ■ • 1 , y V '. , ,i „.. , It ¥»./., » , / - . . .» -*< . ’'"^ V'7-'- ■i'- 'f' ' '^t ' , ' nv ’•- •:: ;. 7 , : f *5^, • f ,fK-; ' ^'' ■ T'' ■. •■<:, •i>m.r- ♦■ ■ .•SI." 7 fresh aqueous solution of Ilethyleno-hlue , The slides remained in this solution from 5 seconds to 1 minute, or longer, depending upon the effect desired. They were then rinsed in v;ater to re- move the surplus stain, and decolorize in alcohol, dried and * counted. 2. Counting. For the purpose of counting' tho slides v/ere examined under the microscope with the high pov/er oil immersion lens. This re- vealed the individual and clusters of "bacteria stained a dark "blue in a light "blue field. The microscope was standardized oy means of a stage micro- meter and so adjusted that each microscopic field covered an area of 1/3700 sq. cm... This gave a microscopic factor of 370,000; that is; the average count per field was multiplied hy 370,000 to give the final count. This was due to the fact that there were 3700 raicrscopic fields per sq. cm., 1/100 cc. of milk was spread over 1 sq. cm. , therefore each microscopic field contained 1 1/370,000 cc. of milk. Duplicate smears \7ere made of each sample of milk and 16 fields of each smear v/ere counted and their average taken for the final count. Oonnts of "both the clusters of one or more bacteria and individual bacteria v;ere made and recorded separately, v/here the clusters consisted of large numbers of individuals an esti- mate was made. D. liethylene-blue reduction Test. A 10 cc. sample of the milk was placed into a sterile test tube by means of a sterile 10 cc. pipette. To this v/as added 0.5 cc. of liethylene-blue solution of such strenght that one part of ■ 'i^Mll(|LS4^ .» : ■- .. -rn*; *-' ■.' 4ti<. - ra^.nc:ir ■ '• ;:.’ raC-t ■ ■; V‘ ‘ y^f ir • ■• ■I a; A>Jl^ *■*• r ‘ In' ' « ..^jr f| . ■ '■ -G. ^ I 'fii « • .« • u .- ip jC % .r'v' '*' ^'r ’^4 • 'L * 4 ^ - ^k- i’ r.->i Jfei.'- - •si'*! . 1 ,. * '.l<' ' ■ ■ ■ ..» ' f :.htd XKi ■ 4 |ir :■< J >-, •. .. /? t : -,. • /* ' ^'1 < ' ^1 - ' ^ 'F '* "^' ,■. '■ • ' .-. . ;Tj ‘-ifc: 7 ^' '■ w V * • ' ' . / , 'fr'tf'.jkiv '"'i J I •. f /> , r' T.^ .f ♦ w I v-ri. .i - - .-r ^;.pf . .'p ' ' ' ’ir”;' • - k^Mriiwkl i . . ." . . ■ tA.. .^ - _ - , - . HiriMi -KMfUAiii irM(nnr|-i > A . - “'* a» rn iCmOb «i i>ri AiWmtfcAKi— '"■* '" "TtS ^' ' -Jg . - 7 i>l ' fi,; K ^ Ot ,1 ■.» 8 the dry d^/e \7as contained to every 200, OCO parts of inilk "by v;eiglit , This solution was made up as follows: The specific gravity of the milk was taken to he 1.032; therefore, the ariount of nilk used v/as 10.32 grams. This would require the solution of Llethylene-hlu! to contain .0000516 grains of dry dye per cc. The solution was mad(| up hy weighing out accurately .1032 grams of Medical I.Iethylene- hlue dye on an analytic balance and dissolving it in one liter of distilled viater. One cc. of this solution contained .0001052 grams of the dry dye and .5 cc. contained the required amount of .0000516 grams of dry dye. The milk in the Methylene -blue solution were thoroughly mix- ed and the test tubes stoppered with sterile cotton plugs and plae ■ ed in an electric incubator where they v/ere held at a constant 0 temperature of 37.5 G.. The time required to decolorise was note,, and recorded. G. Acidity Test. An acidity test was rim on each sample by the following meth- od: 17.5cc. of the thoroughly mixed sample of milk was placed in a white cup by means of a 17.6 cc. pipette. The pipette was rinse;, with distilled water and the rinsings placed in the cup. The per cent acid was determined by means of a j’arrington' s solution which was made up as follows: 50 Farrington's tablets were pulver- ized in a mortar and dissolved in 970 cc. of distilled water. This gave an alkali solution of such strenght that each cc. neu- tralized .Ol^'o acid in 17.5 cc. of milk. Indicator was contained in the tablets. The alkali solution was added drop by drop from a 50 cc . burette mitil a faint pink color appeared and remained for 30 seconds. The per cent acid v;as read directly from the bu- retteby the number of cc. of alkali solution required. -p.rl '■ ^ 'U '■ ’T'S 1tl*t-w: 1 i -”T ' < •^y j a t ar iBs. -I ' r T ;T 1 1 tW^- • 1 V 5-7' .r 0 • "'ii- , . J O' V jv; J/'V.' t “ -1 r^' ■ * , .v/i'. . ♦ . ,r. ^ns .V ■ ' .' J. • - If r'^^» 1 , . ff ’ iv ^ >:/ r ' J .’ ' ii-3*.9^^C.-\i' ' 0\I~V ' * JSIK". •'• '.irf Ji',. V5i -^C**' .-fe *i*-' ',**f ‘X J ( ; _-;. D^r f J'.^' _ /.I -.¥58 .^VJ -•(: /t'ft f *4*'**'^ ’jJL • {, ' * ./ i\' JC, y’-'’^', ^ : , . i* ' ',i;> * .'>, .i V-j "vQ.;oJ 1 73 ■•V, , :■ ‘.-, y ••^. . V r-^ . a . it-r;^'" ' I , .■■■ ■' ’ " ■ ■■'■ M V ;} ■ . Mj A. \T TO ;■ 5^: ■5SL-3iri&» ,; : . ■ • ‘ ■ • • ■¥ \ ., \S. ^i.-* • . ■• J- r>*.' • (. .UdM f,,' I >.■ I - 'k. *f ' At t ai' :o .. , o'’ . ^ »• , LrJ,:^ i*’" ■; ■¥ • H.:; ’..0.. •.'' S u V -;kL::ir.:<-'.- .^\a■^.- iJJi. ' ' ■’ V^‘" ■■ , o3 <-^y ’^'’ , '!;.i /jL vov ‘ vl a-i', • -Tl^-*’ -1 .'L ^ * , • # • • . - , MV* 4 ’ ,' V :l:tixh- .. "■•will Mj''! 1^ t’ , lY. HJSPERHi'LElTTAI. . The Experimental data of this investigation is presented in tabular form on the follov/ing pages. TABLE I Corcplete data in Chronological Order o [-f-1 m o ITV o irv o iTV vX) CM CM 2 o o I — r— VD IfV CO r— VO f — irv CO -H r-t rH rH rH rH rH rH rH rH t—i rH rH r*i rH O • -4J D o o U'V irv u^ o IT\ o o IfV o O o o # • • • • # • • • • • # • • rd V.O -d" C<^ r- CM irv VO CO t4-V -d- d" KV o> CO Redaction Tinr.e i? 1 O O 9 O 1 — i 1 irv irv 'T o irv rH 1 uv f-C 1 VO 2 O O CO 7-10 8 1 o o I irv J- irv CM cIj s 1 d 4^ c >s > > o o d o o o o o o o 8 CM o O o d d o -d- 2 0) o CO o CO o o o o o CO 8 o CO o o «» m «» •• «• «» -d- CO o o CM o rH 'iR CM o KV j _d- iH CM VD VO cT CM 1 » (M 1 CM VO rH CO crv 1^ KV 8 m tj K) CM CM IfV rH ov irv •• m ** M rH 4 d CM iH IfV CM rH • o o^ CVl rH -4-* d 8 o o 8 8 O 8 O 8 8 g o o g o o 8 8 8 y o o o o o o o o o o o o <» m •» m •» «• •* •* o CVJ CO o O o 1 — o irv o irv iTv o o iH rH o U"V VO t^v o iH o irv I — o to •■* d VX) crv rH rH rH PL4 (4 • <1> 1 — CO o^ o rH CM KV irv r— 05 a rH rH pH CM CM CM CM CM CM CM CM 0> rH ^ i 1 CO 0 1 — irv CM rH CM VD irv CM CO r^ CO CM S' iH '8 d CM S' rH iH rH rH rH rH rH rH rH rH rH •H iH rH CM CM CM CM CM CM CM CM CM CM CM CM CM CM t ‘ I ) ■ t < t n««!adil*a . ' I t t t , / . r. , I . , I . , ■ V » » ' I > ^ i 1 I i I s •I > I • r I I- ! I • r J V ii” I ( !. ( I ■ I » . 3 t I > .. ■?/ t . ; ^ ' >■ i I ] I I • *.• > ■• . ^ ^ c. /*7 • ■ ^ •«’ /ri ' .' *'l ,' ►* ', ' n. , ’I ■ , i > I t 3 1 { I < »• I y M X 1 ' t ■" ■’ T> \\ ■‘•r: .‘i'K A, ti\ V' 1 i>; - TV.*: nJi Mf SrfK e Xtt S W ^^ W V ' ll' } I ii I || TABLE I (Cont*d) » 4- r~- CM to CM ITN cr» CO 60 rH CM OJ r<\ *r r— rr> VD w t— CO VO r~- VO 9^ rH VD ir\ VO rr rH rH i-l fH rH rH rH rH rH rH CM rH rH rH *r c • < a £ o O O m ir> O ir» o o o O ir\ o o •r « • • « • • • • • • # • • t: ITv ITk CM CM CM lOr io> VO irv irv o ir» c CM V c o -H c £ O tH ITV rH LTV rH 8 8 ITv CM ir» CM lO rH o rH o o o o 9 35 2 s ^ E- 1 1 1 1 h 1 9 9 9 9 9 9 9 9 Tl CTv o c:> rH KV CM rH 1 — LTV CM rH O'N © rH rH rH rH rH fH rH rH C O 8 VJD o o o o O O O o o O LC\ o c a s s o CM 8 o 60 rH r— o 60 o m .g 8 O to r— o o 4J t — VO 1^ 8 CD CD r— ICD 8 r> CM a rH rH rH S' rH rH 60 o c J. rH CM rH pt r- O O o 000 o O o a O V£> O rH o CM 8. O 60 o ® t: m «k ■ft ® •«■ Jj" 1 f j j 1 VD cr> VO 9 9 rH IfV CM 1 j i 1 9 60 J- VO J 1 VO PP r KV rH P S“ K- X-^ • y — ■ Tl « O Q K\ o 8 o 1 o o VO o o 60 to rH VD oj iH rH rH o cr> crv rH PM CM cr» CM rH » cQ (D cn o rH CM -=^ ICD VD 60 (TV o rH CM «$ ^ I IT\ VO VD VO VD VO VO VD VD VO VO r- 9^ S V rH O PP PP S< a W ^ • (U 9 Pm if 1^ f 1^. rH KV 8 22 CM rH rH rH rH rH iH rH rH rH rH rH CM CM CM CM CM CM CM CM CM CM CM CM CM CM ■« • . • V , \ I I t ( t . I C r., r r I ‘ r (-T t, !Vhi>' '■' V I • \ . 1 I TABIiE I (Cont’d) > . 16 ' •fH CM ir» CM CM iH 0 ! 0 * to CM |H CM - 4 ’ T 60 r— VD VO vD t'- 60 a\ f — 60 VO N- rH 1 — i iH rH rH rH rH rH rH rH r-l rH rH rH t 0 0 0 10* 0 ir\ 0 0 ir> 0 •H • 0 tr\ • 10 • m 0 iC\ i/: • 0 • ITv • -rf • 0 • r— • ir\ o rH rH m C o ■t“ ! u o S 2 8 8 0 CM 0 rH 8 2 8 8 8 CM gr* 8 8 * 1 CM 1 CM 1 ir\ 1 LO> g cr* 1 60 .A 1 0 g 60 1 cr* ® EH K rH j: p 0 8 - 4 ' >» 0 c Q 0 0 0 8 0 0 0 0 «5 0 u § 0 0 0 VO 2 2 0 0 8 0 60 cd 0 0 VO 0 60 m m m m ,d • a 0 0 K\ 60 0 - 4 " - 4 ^ 60 - 4 - ir* 8 * c r~- 60 VO O'* o^ VO 60 60 0 0 0 rH CM EH 8 0 0 0 0 0 2 0 0 0 > 0 0 r~ 0 0 0 0 0 0 0 0 aJ 0 0 fl! V£) ITN 60 0 CM CM CM 60 0 cr* ® 0 •d p •» «k a» «• g ® ± rH rH CTv cr» 0 0 1 O'* 60 CM - 4 " ® •«- CM VX> h- VO r — t'- 0 0 CM 0 1 — ■?x P« t> CM CM VO IT\ 0 rH PP ;r m •• m. Eh r*^ rH KN rH rH P 1 - >> > , 0 0 0 0 0 0 0 0 0 0 nJ 0 0 P 0 0 0 0 0 0 h- 0 2 0 ® 0 •d « K\ CM K\ VO CT* CM VO .d CM ® *: M •• «» «» •» ! «« • 0) R CM CM CM r~- O'* 1 rH #H h- 0 0 M p rH rH 60 r-J J- j" , 4 " CM 0 rH m r- rH J- IC> CM |H fH c » 4^ C r 8 8 8 8 8 0 0 8 0 0 0 0 8 8 8 0 0 8 c 0 0 0 0 0 0 0 VO 0 0 0 0 0 0 c m m j- 0 -iS" KV 10 CM ,4" 6- 8 60 VO rH LO a CM vD CM 60 CT> CM rH to CM gH'* 60 4 : CM rH rH cr* rH - 4 ’ CM crx a 1“ 0 ft rH P . c -5 VD r — to S' 0 fH CM ir\ t cfl g 0 0 0 0 0 0 iH fH rH 4 I » t 4 1 I I ‘ t ■ I ' ; I . TABLE II CLASS "A" Comparison of Standard Plate Counts 17 ’ to Frost Counts. ITo. Plate Count Frost Count ITo. Plate Count Frost Count ' 18 18,000 14,400 47 39,000 17,600 19 100,000 8,400 48 100,000 34,000 21 60,000 24,800 49 47,750 31 , 200 22 37,000 14,800 50 18,000 19,200 23 400,000 280,000 51 23,000 28,400 24 15,000 22,000 52 31,500 27,200 25 40,000 100,800 53 40,375 32 , 800 27 55,000 258,400 54 23,750 18,400 28 75,000 17,200 55 25,800 40 , 800 31 261,000 16,000 56 28,600 19,200 33 100,000 60,800 57 30,750 22,000 34 70,000 29,200 58 26,100 28,000 35 51,000 129,600 59 19,700 34,400 36 60,000 30,400 60 6,250 7,600 38 92 ,000 149,600 61 11,900 16,400 39 182,000 148,700 62 8,800 13,200 40 26,000 49 , 200 63 19,050 20,800 41 10,000 4,800 64 4,950 14,800 42 70,000 569,930 65 203,500 490,710 43 15,000 18,800 66 9,450 10,800 44 136,000 27,600 68 4,500 35 , 600 Clas s ”A" includes all milk v/itk a PI ate Count of less than 500, 000 per cc. V .. 7 \ ? I f TiiSIiE II (Conf d) 18 ' ITo. Plate Comit Frost Count llo. Plate Count Frost Count 69 8,500 28,800 91 4,550 7,200 70 98,500 184,800 92 8,500 42,800 71 241,000 200,745 93 5,900 6,200 72 136,000 132,000 94 22,400 20,400 74 14,000 34,000 95 6,800 6,200 75 60,000 38,400 97 64,700 109,200 76 325,000 67,600 99 306,000 288,000 77 387,000 1,268,820 100 228,000 29,200 78 28,500 24,400 101 117,000 78,000 79 11,400 10,000 102 6,700 123,200 80 142,000 L, 427, 520 103 34,000 30,400 81 1,900 46 , 400 104 20,000 70,000 82 12,000 27,600 105 264,000 83,600 83 12,750 31,200 106 123,000 40,600 84 14,250 32,000 107 85,000 68,400 85 22,450 42,000 108 392,000 90,400 86 108,000 97,200 109 123,000 194,400 87 29,900 216,000 110 4,600 4-4,000 88 28,200 92,000 111 17,000 163,200 89 18,300 44,400 113 188,000 84,400 90 11,800 12,200 114 426,000 -- 115 231,000 105,600 . ; — tit..- t r * f / .49. ; Ti\3LS III CLASS ”A” Comparison of Standard Plate Counts to Breed Clusi 19 er Counts’. llo. Plate Count Breed Cluste r ITo. Plate Count Breed Cluster - 18 18,000 12,300 47 39,000 24,600 19 100,000 — 48 100,000 24,600 21 60,000 12,300 49 47,750 — 22 37,000 36,900 50 18,000 — 23 400,000 147,600 51 23,000 12,300 24 15,000 24,600 52 31,500 — : 25 40,000 98,400 53 40,375 12,300 27 55,000 258,300 54 23,750 — 28 75,000 135,300 55 45,800 . — 31 261,000 — 56 28,600 24,600 33 100,000 12,300 57 30,750 12,300 34 70,000 61 , 500 58 26,100 — 35 51,000 — '59 19,700 12,300 36 60,000 -- 60 6,250 -- 38 92,000 49,200 61 11,900 -- 39 182,000 12,300 62 8,800 -- 40 26,000 -- 63 19,050 -- 41 10,000 12,300 64 4,950 __ 42 70,000 24,600 65 203,500 24,600 43 15,000 12,300 66 9,450 12,300 44 136,000 36,900 68 4,500 — Class "A” includes all milk with a Plate Count of less than 500,000 per cc. If im y-i. T*) ] i f V f t 1 I 1 i i u ., : t 4 TABLE III Cont'd) 20 ' ITo. ?late Count I ireed Cluste] » ITo. Plate Coujit Breed Cluster 69 8,500 — 91 4,550 — 70 98,500 24,600 92 8,500 12,300 71 241,000 36,900 93 5,900 -- 72 136,000 49,200 94 22,400 49,200 74 14,000 24,600 95 6,800 -- 75 60,000 12,300 97 64,700 270,000 76 325,000 56,900 99 306,000 430,500 77 587,000 282,900 100 228,000 24,600 78 23,500 -- 101 117,000 Too heavy 79 11,400 — 102 6,700 73,000 80 142,000 356,700 103 34,000 12,300 81 1,900 12,300 104 20,000 12,300 82 12,000 12,300 105 264,000 787,200 83 12,000 — 106 123,000 12,300 84 14,250 12,300 107 85,000 147,600 85 22,450 12,300 108 392,000 479,700 86 108,000 12,300 109 123,000 47,970 87 29,900 12,300 110 4,600 -- 88 28,200 12,300 111 17,000 541,200 89 18,300 12,300 115 188,000 147,600 90 11,800 — 114 426,000 Too heavy 115 231,000 49,200 v*?i . * 1 f fl 9 9 e t 7 ? / > I f ( ? t 9 i 5 . : r . . . rjT T I i t 9 f ■V r,'v f . k« •* ■ V TABLE IV CLASS " A” 21 Comparison of Standard Plate Counts to the Breed Individual Counts ITo. Plate Count Breed Ind. Bo. Plate Count Breed Ind. 18 18,000 223,900 47 39,000 98,400 19 100,000 — 48 100,000 36,900 21 60,000 24,600 49 47,750 -- 22 37,000 61,500 50 18,000 — 23 400,000 1,512,900 51 23,000 24,600 24 15,000 86,100 52 31,500 — 25 40,000 196,800 53 40,375 36,900 27 55,000 7,537,400 54 23,750 -- 28 75,000 282,900 55 45,800 — 31 261,000 — 56 28,600 49,200 33 100,000 24,600 57 30,750 36,900 34 70,000 209,100 58 26,100 — 35 51,000 — 59 19,700 24,600 36 60,000 — 60 6,250 — 38 92,000 123,000 61 11,900 — 39 182,000 123,000 62 8,800 -- 40 26,000 — 63 19,050 — 41 10,000 98,400 64 4,950 -- 42 70,000 282,900 65 203,500 86,100 43 15,000 49,200 66 9,450 49,200 44 136,000 86,100 68 4,600 — Clas 50C, s "A" includes all milk v;ith a Plate Count of 000 per cc. less than f x-^ 'U- f 5"<-asgs TABLS IV (Cont’d) 22 ' ITo. Plate Coimt Breed Ind. ITo. Plate Count Breed Ind. 69 8,500 — 91 ■ 4 , L'L»0 70 98,500 61,500 92 8,500 61,500 71 241,000 73,800 93 5,900 -- 72 136,000 135,300 94 22,400 693,600 74 14,000 61,500 95 6,800 -- 75 60,000 12,000 96 64,700 666,000 76 326,000 73,800 99 306,000 1,940,700 77 387,000 750,300 100 228,000 196,800 78 23,500 -- 101 117,000 Too heavy 79 11,400 -- 102 6,700 430,500 80 142,000 3,161,100 103 34,000 24,600 81 1,900 24,600 104 20,000 61,500 82 12,000 615,000 105 264,000 3,271,800 83 12,750 -- 106 123,000 369,000 84 14,250 24,600 107 85,000 1,279,200 85 22,450 49,200 108 592,000 3,370,200 86 108,000 615,000 109 123,000 600,240 87 29,900 1,230,000 110 4,600 — 88 28,200 49,200 111 17,000 1,303,800 89 18,300 49,200 113 188,000 528,900 90 11,800 -- 114 426,000 Too heavy 115 231,000 172,000 -V if I 5 . . . 1 25 TABLE V CLASS "A” Conparison of Standard Plate Counts to the hethylene Blue Reduetion Tests. Time Recorded in Hours and Minutes. Ho. Plate Count Reduction Ho. Plate Count Reduction 18 18,000 6-00 47 39,000 8-45 19 100,000 5-10 48 100,000 8-40 21 60,000 4-15 49 47,750 9-00 22 37,000 6-15 50 18,000 8-45 23 400,000 3-40 51 23,000 9-00 24 15,000 8-00 52 31,500 9-20 25 40 , 0.00 7-10 53 40,375 8-40 27 55 ,000 5-00 54 23,750 9-20 28 75,000 4-30 55 45 , 800 11-15 31 261,000 7-00 56 28,600 11-10 33 100,000 7-30 57 35,750 8-00 34 70,000 7-30 58 26,100 IOtOC 35 51,000 7-00 59 19,700 9-15 36 60,000 7-00 60 6,250 10-15 38 92,000 6-00 61 11,900 10-00 39 182,000 6-15 62 8,800 11-40 40 26,000 6-30 63 19,050 13-25 41 10,000 6-45 64 4,950 12-25 42 70,000 5-00 65 203,500 11-15 43 15,000 8-45 66 9,450) 7-10 44 136,000 7-45 68 4,500 12-00 Class "A” includes all milh v;ith a Plate Count of less than 500,000 per cc. p i If. A . Oc' Ah TABLE V (Cont’d) 24 ' llo; Plate Count Reduction IIo. Plate Count Reduction 69 8,500 11-40 91 4,550 9-40 70 98,500 9-35 92 8,500 8-20 71 241,000 4-40 93 5,900 8-50 72 136,000 4-40 94 22,400 12-00 74 14,000 11-15 95 6,800 12-00 75 60,000 10-45 97 64,700 4-20 76 325,000 5-50 99 306,000 5-20 77 387,000 4-40 100 228,000 12-00 78 23,500 10-30 101 117,000 00-35 79 11,400 10-30 102 6,700 12-00 80 142,000 9-25 103 34,000 9-40 81 1,900 11-05 104 20,000 12-40 82 12,000 10-30 105 264,000 2-20 83 12,750 9-00 106 123,000 5-20 84 14,250 8-20 107 85,000 5-20 85 22,450 8-20 108 392,000 3-10 86 108,000 7-00 109 123,000 5-20 87 29,900 9-00 110 4,600 9-40 88 28,200 8-20 111 17,000 8-20 89 18,300 9-40 113 188,000 5-20 90 11,800 8-20 114 426,000 0-52 115 231,000 8-20 'i . Si >'• i, F f ■ \ I ' ■ ^ ' i* t • i :.M TABLE 71 CLASS ”A" 25 ' Comparison of Standard Plate Counts to the Acidity Te sts. Eo. Plate Count •H O ITo. Plate Count fo Acid 18 18,000 .175 47 89,000 .157 19 100,000 .170 48 100,000 .154 21 60,000 .150 49 47,750 .158 22 37,000 .145 50 18,000 .163 23 400,000 .180 51 23,000 .147 24 15,000 .175 52 31,500 .147 25 40,000 .166 55 40,375 .213 27 55,000 .15E 54 23,750 . .162 28 75,000 .148 55 45,800 .164 31 261,000 .154 56 28,600 .188 33 100,000 .130 57 30,750 .188 34 70,000 .186 58 26,100 .210 35 51,000 .160 59 19,700 .177 36 60,000 .167 60 6,250 .193 38 92,000 .179 61 11,900 .162 39 182,000 .143 62 8,800 .188 40 26,000 .165 63 19,050 .174 41 10,000 .178 64 4,950 .182 4S 70,000 .165 65 203,500 .165 43 15,000 .168 66 9,450 .179 44 136,000 .169 68 4,500 .178 Class "A" includes 500,000 per cc. all milk v/ith a Plate Count of less than j- V ' I . ■■ ..-J ,( « * ^ TABLE VI (Conf d) 26 !l . 1 ♦ o Plate Count io Acid ITo. Plate Count fo Acid 69 8,500 .211 91 4,550 .195 70 98,500 .162 92 8,500 .175 71 241,000 .152 93 5,900 .182 7E 136,000 .163 94 22,400 .159 74 14,000 .154 95 6,800 .175 75 60,000 .172 97 64,700 .175 76 325,000 .162 99 306,000 .178 77 387,000 .158 100 228,000 .200 78 23,500 .162 101 117,000 .210 79 11,400 .182 102 6,700 .174 80 142,000 .161 103 34^,000 .182 81 1,900 .182 104 20,000 .175 82 12,000 .184 105 264,000 .164 83 12,750 .163 106 123,000 .162 84 14,250 .191 107 85,000 .162 85 22,450 .171 108 392,000 .171 86 108,000 .174 109 123,000 .170 87 29,900 .186 no 4,600 .175 88 28,200 .182 111 17,000 .188 89 18,300 .171 113 188,000 .171 90 11,800 .165 114 426,000 .182 115 231,000 .174 J*'r9'*Tr; ‘f* t t e ^.:7 TABLE YII CLA3;: "A" Comparison of Standard Plate Counts to the Sediment Tests. Sediment expressed in Mgs. per Pint. Ho. Plate Count Sediment Ho. Plate Count Sediment 18 18,000 4.0 47 39,000 1.5 19 100,000 3.5 48 100,000 2.0 21 60,000 2.5 49 47,750 2.0 22 37,000 5.0 50 18,000 2.5 23 400,000 3.5 51 23,000 3.0 24 15,000 6.0 52 31,500 7.5 25 40,000 8.0 53 40,375 30,0 27 55,000 3.0 54 23,750 4.0 28 75,000 4.0 55 45,800 2.0 31 261,000 3.0 56 28,600 2.5 33 100,000 1.0 57 30,750 2.0 34 70,000 1.0 58 26,100 1.0 35 51,000 8.0 59 19,700 5.0 36 60,000 2.0 60 6,250 5.0 38 92,000 7.5 61 11,900 2.0 39 182,000 10.0 62 8,800 2.5 4o 26,000 7.5 63 19,050 2.5 41 10,000 5.0 64 4,950 5.0 42 70,000 1.0 65 203,500 4.5 43 15,000 5.0 66 9,450 5.0 44 136,000 7.5 68 4,500 5.0 Class "A" includes all milk with a Plate Count of less than 500,000 per cc. * ' * . ■ ■ * ~ * 1 - < 1 .1 ■ 1 .. . ■ -Ml 1 .. . > 28 ' TABLE VII (Conf d) llo. Plate Count Sediment llo. Plate Count Sediment 69 8,500 5,0 91 4, 550 4.0 70 88,500 3,0 92 8,500 2.0 71 241,000 20.0 93 5,900 2.0 72 136,000 5.0 94 22,400 2.5 74 14,000 8.0 95 6,800 7.0 75 60,000 2.6 97 64,700 6.0 7b 325,000 6.0 99 306,000 4.0 77 887,000 0 4.0 100 228,000 5.0 78 23,500 6.0 101 117,000 9.0 79 11,400 20,0 102 6,700 7.5 80 142,000 15.0 103 34,000 4.5 81 1,900 7.5 104 20,000 3.5 82 12,000 4.5 105 264,000 5.5 83 12,750 3.5 106 123,000 5.0 84 14,250 4.0 107 85,000 5.0 85 22,460 4.0 108 392,000 15.0 86 108,000 3.5 109 123,000 3.5 87 29,900 4.0 110 4,600 4.0 88 28,200 4.0 111 17,000 5.5 89 18,300 4.0 113 188,000 5.0 90 11,800 4.0 114 426,000 10.0 115 231,000 7.5 - Ho. Plate Coimt Erost Coiuit IIo. Plate Count Erost Count 29 900,000 356,800 67 995,000 3,717,500 30 680,000 132,000 73 910,000 942,460 32 640,000 2,862,000 112 920,000 88,800 46 672,000 260,225 TABLE VIII class "B” CoLiparison of Standard Plate Counts to Erost Counts. Class ”B" includes all milli with a Plate Count of 500,000 to 1,000,000 per cc. TABIdil IZ OInVSS "B" Comparison of Standard Plate Co unis to Breed Cluster Counts ITo. Plate Count; 3reed Cluster ITo. Plate Count Breed Cluster 29 900,000 67 995,000 1,887,000 30 680,000 73 910,000 390,400 32 640,000 615,000 112 920,000 221,400 46 672,000 36,900 Class ”B" includes all milk with a Plate Count of 500,000 to 1,00Q,C00 per cc. TABLE Z CLASS "B" Comparison of Standard Plate Counts to Breed Individual Counts ITo. Plate Count Breed Ind. ITo. Plate Count Breed Ind. 29 900,000 67 995,000 4,566,000 30 680,000 73 910,000 2,201,700 32 640,000 1,720,000 112 920,000 1,599,000 46 672,000 98,400 Ulass "B" inciuaes ai.i m.iim *wi un a ruaue counu or 500,000 to 1,000,000 per cc, I i » • « • i ( x*r< j*'. • *'Vj TABLE XI CLASS "B" Comparison of Standard Plate Counts to Reduction Tests. Time Recorded in Hours and Llinutes. 30 ' the llethylene Blue ITo. Plate Count Reduction ITo. Plate Count Reduc tion 29 900,000 0-25 67 995,000 5-0 30 680,000 4- 0 73 910,000 4-40 32 640,000 7- 0 112 920,000 5-20 46 672,000 4-45 Class "B” includes all milh v/i’ fch a Plate Count of 500,000 to 1,000,000 per cc. TABLE XII CLASS "B" Comparison of Standard Plate Counts to Acidity Tests. ITo. Plate Count ^0 Acid ITo. Plate Count fo Acid 29 900,000 .171 67 995,000 .168 30 680,000 .180 73 910,000 .157 32 640,000 .179 112 920,000 .192 46 672,000 .179 Class "B" includes all milli uith a Plate Count of 500,000 to 1,000,000 per cc. TABLE XEII CLiiSS "B" Comparison of Standard Plate Count to the Sediment Tests. Sediment expressed in Mgs. per pint. ITo. Plate Count Sediment ITo. Plate Count Sediment 29 900,000 4.0 67 995,000 4.0 30 680,000 3.0 73 910,000 5.0 32 640,000 3.5 112 920,000 4.5 46 67^,000 6.5 Class ”B” includes all mil A v/ltli a Pla'' be Count of 500,000 to 1,000,000 per cc. • • * f 1 J f‘ : i 'J \ 3 f /• \ f 9 :■! . • vy ' « A1 Ho. Plate Counts Frost Count Ho. Plate Count Frost Court 17 6,012,000 Too heavy 45 7,100,000 10,000 20 19,650,000 Too heavy 96 1,150,000 117,200 26 1,100,000 61,200 98 1,094,000 2,253,250 37 2.490.000 1.858.750 117 10.985.000 230,800 TABLE XIV Class "C” Comparison of Standard Plate Counts to Frost Counts. 31 Class "C" includes all milk v/ith a Plate Count of over 1,000,000 per cc. TABLE XV CLASS ”C" Comparison of Standard Plate Counts to Breed Cluster Counts. Ho. Plate Count Breed Cluster ITo. Plate Count Breed Cluste]' 17 20 26 37 6,012,000 19 ,650,000 1.900.000 2.490.000 9,472,000 12,210,000 550,000 270,600 45 96 98 117 7.100.000 1.150.000 1.094.000 10,985,000 Too heavy Too heavy 1,143,900 110,700 Class "C” includes all milk with a Plate Count of over 1,000,000 per cc. TABLE XVI CL/iSS ”C" Comparison of Standard Plate Counts to Breed Individual Counts. Ho. Plate Count Breed Ind. Ho. Plate Count Breed Ind. 17 20 26 37 6,012,000 19,650,000 1.900.000 2.490.000 21.830.000 30.230.000 6,970,000 668,800 45 96 98 117 7.100.000 1.150.000 1.094.000 10,985,000 Too heavy Too heavy 3,456,300 344,400 Class "C" includes all milk with a Plate Count of over 1,000,000 per cc. : .V: , 1 r r < f f C TABLE XVII CLASS "C" Comparison of Standard Plate Counts to Methylene Blue Reduction Tests. 32 Ti m<^ iTo. : ?late Count .U UJ. U Ctllu. XdXil Reduction . u c s • ITo. Plate Count Reduction 17 6,012,000 0-45 45 7,100,000 O-IO 20 19,650,000 0-45 96 1,150,000 0-35 26 1,900,000 I- 0 98 1,094,000 I-IO 37 2,490,000 10-40 II7 10,985,000 9-50 ({Jlass "C-' includes all milk with a Plate Count of over 1 , COO , CCC vor i^- c . TiOBLS XVIII CLASS "C" Comparison of Standard Plate Count to the Acidity Tests. Ho. Plate Count fo Acid ITo. Plate Count fo Acid 17 6,012,000 .130 45 7,100,000 .383 20 19,650,000 .165 96 1,150,000 .174 26 1,900,000 .172 98 1,094,000 .181 37 2,490,000 .152 II7 16,985,000 .164 Class "C" includes all milk with a Plate Count of over I ,000,000 per cc. TABLE XIX CLASS "C" Comparison of Standard Plate Counts to the Sediment Tests Sediment Expressed in Mgs. per Pint. ITo. Plate Count Sediment Ho. Plate Count Sediment 17 6,012,000 6.0 45 7,100,000 7.5 20 19,650,000 7.5 96 1,150,000 5.0 26 1,900,000 7.5 98 1,094,000 3.5 37 2,490,000 3.5 II7 10,985,000 5.0 Class 1,000 "C" includes ,000 per cc. all milk with a Plate Count of over t ? t J Jh f t t TABLE XX CLASS "A" Comparison of Breed Cluster Counts to 33 the Breed Individual Counts. ITo. Breed Cluste r Breed Ind. ITo. Breed Clustei Breed Ind, 18 12,300 223,900 59 12,300 24,600 21 12,300 24,600 65 24,600 86,100 22 36,900 61,500 66 12,300 49.200 23 147,600 1 , 512,900 70 24,600 61,500 24 24,600 86,100 71 36,900 73,800 25 98,400 196,800 72 49,200 135,300 27 258,300 7 , 537,400 73 390,400 2 , 201 , 700 28 135,300 282,900 74 24,600 61,500 33 12,300 24,600 75 12,300 12,300 34 61,500 209,100 76 36,900 73,800 37 270,600 668,100 77 282,900 750,300 38 49,200 123,000 80 356,700 3 , 161,100 39 12,300 123,000 81 12,300 24,600 41 12,300 98,400 82 12,300 615,000 42 24,600 182,900 84 12,300 24,600 43 12,300 49,200 85 12,300 49,200 44 36,900 86,100 86 12,300 615,000 46 36,900 98,400 87 12,300 1 , 230,000 47 24,600 98,400 88 12,300 49,200 48 24,600 36,900 89 12,300 49,200 51 12,300 24,600 92 12,300 61,500 53 12,300 36,900 94 49,200 693,600 56 24,600 49,200 97 270,000 666,000 57 12.500 56.900 99 450 .500 1,09^,700 Cla£s__"A” includes all milkjzith a Pinti? rvf than_ JQO . coo . 34 TABLE :DC(Cont’d) llo. Breed Cluste: 1 * Breed Ind. IIo. Breed Cluster Breed Ind. ' 100 102 103 104 106 107 24,600 73,800 12,300 12,300 12,300 147,600 196,800 430,500 24,600 61,500 369,000 1,271,200 108 109 112 113 115 117 479.700 47,970 221,400 147,600 49,200 110.700 3,370,200 600,240 1,599,000 528,900 172,000 344,400 TABLE XXI CLASS ”B" Comparison of the Breed Cluster Counts to the Breed Ind* Counts. llo. Breed Cluste: : Breed Ind. ITo. Breed Clustei Breed Ind. 26 52 555 .000 615.000 6.970.000 1.720.000 105 111 787.200 541.200 3,271,800 1,303,300 Class ”B” includes all milk with a plate count of 500,000 to 1,000,000 per cc. TABLE XZlI CLASS ”C" ! Comparison of the Breed Cluster Counts to the Breed Ind. Counts. ITo. Breed Cluste c Breed Ind. ITo. Breed Clustes Breed Ind. 17 20 9,472,000 12,210,000 21.830.000 30.230.000 67 98 1,887,000 1,143,900 4,366,000 3,456,300 Class ”C" includes all milk v/it 1,000,000 per cc. h a plate count of over C 35 TABLE XXIII Distribution of Milk into the three classes by the various methods used. Classes Plate Erost Breed Cluste r Breed Ind, Class "A" 85 82 83 67 Class 7 1 1 0 Class "C" 8 4 5 6 Totals 100 87 89 73 Classification was made according to the results obtained by the Standard Plate Method. -r Qjf I J ■ fr) iw ^ «-. ' i' 1 i I f J H r I rV I CHART- 1 3 J?TED - INO I V Breed- CLu^tetr 7T?06T 'PlATE so a 000 \ : I ; i 1 . _1 1 I 1 /oo <^0 zo ^0 so -fo so zo o 20 so -jta A/ur^&ER OF SAtAPLE5 breed -Indwidual -CLUSTEJ5 TF05T VLATE all others 600,000-/, 000,000 I . . , I i 1 I ; I /eo OO 3 oTv Topy ^-o 3 o ao /o o -o ao so sf> 2 5 Mgs Acidity— ./SO 25 /? 30 29 u ^.0 AAfi. Acidity-.780 55 52 , -Ik-V-Vv : iV /OMgs SOMgs 20/Y a V' : 'V.. ■1 f-:Tai ■oBJP', V 'i -jj-i ? 4 ^!’ *f > .4 • f * 1 - I .:. :rr‘ ?»♦ 1 ) f • "v " ' ..’iMH ' IIP ,i. y -C ■» .' ■■ J’" j ,i i ' ^ ^■ ' l» ^ . •. .5 , ;% ■ ' ?■ AmO . i fy ' 'irtr^ .. .... # ‘■•i ^ 4 , - ■ ' .:’ 'cf , ,j ■., ' • i : -. i, > .i;.- ' :■; -i '' V ' *Jt£i ) ' ' <1 1 -. ,'"i„ ■*‘^- • ' ... ■ :v-‘ ” l'|.. /' •,. >’S*'i ■'• ■ ' „)f --’n ■ ■ '. . '■ ■■'■ ' J . 4 'A-/. .▲ ' .1 . ^ 43 While these comparisons \:ere made according to the classiiic- , ation made on page 35, attention is called to the fact that the methods are highly reliable in grading milk having a germ content , of less than 100,000 per cc.. 59 samples of this investigation had | a Plate count of under 100,000 per'cc.; of these 59, the Prost method placed 51 in a class of under 100,000 per cc. v/hile Breed (cluster) placed 56 in this class, hut on 24 of these no count was obtainable by the latter method; therefore, it was not considered quite as reliable as Prost. Prom this it may be said that even in very high grade milk any of the three methods is quite reliable, the Plate and Prost methods being more so than the Breed. fables YIII, IX and X, XIV,XVand XVI seem to indicate that the results obtained by the Breed method correlate raore closely with the Plate counts than do those obtained by the Prost method. Prom a careful study of fables V, XI and XVII it may be con- cluded that a short deduction is of great significance, in that almost invariably a short Reduction indicates a high count, while on the other hand a high count does not necessarily mean a short Reduction. Samples 101 and 114 in fable V had a short Reduction test, v/hile the bacterial count was comparatively lov/. In fable XVII, samples 37 and 117 had a high count and a long Reduction tes1 , which would indicate that a long Reduction test does not have as much significance as does a short one. these fa,bles lead the au- thors to think that it is the kinds of organisms rather than the number of organisms that influence the Reduction time; however there is hardly enough data to draw definite conclusions. fhe data on fables VI, XII and XVIII indicate that there is no definite correlation between the acidity of the milk and its nerm con te n t ■ .. ■ - - A • t 1 ) jl 't I I i ( ( FT- t !l I m ' M <• P ' ,•■ f ft' -41 45 VI. smiMAP.Y AlID COl'IGLUSIOlTS. It was found in this investi^ntion that any of the three meth- ods of hacterial analysis of milh, namely: Standard Plate method, | ij’rost "Little” Plate method, and Breed method may he successfully used as a basis for grading market milk, fhe adaptability of each method depends upon other factors than its accuracy. The i'rost method is more reliable than the Breed method in grading milk of low germ content, but not as reliable for more highly contaminated m.ilk, unless dilutions are ma,de for the ±^rost plates . iThere the Breed method is used as a basis of grading milk, the cluster counts should be averaged for the final count rather than the individual counts if the Standard Plate method is accepted as a basis and a close correlation is desired. The authors are of the opinion that the variations between the Methylene -blue Keduction tests and the Plate counts are too great to warrant their use as a basis of grading milk, but that Methylene - blue Reduction tests have value as an indiction of the keeping quad - ity of railk. Sediment tests have no relation to the germ content of a sam- ple of milk but it is the opinion of the authors that they are an indication as to the sanitary conditions under which the milk was produced and, as such, are of value in a system of grading milk, and majr be successfiuLly used as an incentive for the production of cleaner milk. There is no correlation between the acidity and the germ con- tent of a sample of milk, but it is thought that some light is thrown upon the sanitcry conditions of its production anid subse- Quent handllnr? and that it is an index as to its koeoinr: quality.