SANITARY ASPECTS OF MILK BY GAIL MONROE DACK THESIS FOR THE DEGREE OF BACHELOR OF SCIENCE IN AGRICULTURE COLLEGE OF AGRICULTURE UNIVERSITY OF ILLINOIS 1922 / I \ i / L < I . : x:- Digitized by the Internet Archive in 2016 https://archive.org/details/sanitaryaspectsoOOdack TABLE OF COirrENTS Certific ate. Table of Contents. I Introduction. II General Milk Contamination. III Epidemiology of Milk. IV Relation of Milk to Infant Mortality. V Lactic Acid Bacteria. VI Milk Pasteurization. x’’ \ ^ ■ KT i^’' V.;.: avji»i4 ’ j:'i^mv:‘<4. gjBBIir : '^"‘im^isi ■' w^ '"■ Kc^Sr-v.-tv- -i; ,T "V ■ '•■■ A^i '.' ‘ . • ’.*■,... >:i‘ \ ^^^rv:vtes -SER^ »T? 4 ; v'.’.r .. '•'...« ‘ A v;\vMt * > ’■ . K‘ Jl:'>- ■' ■■ -m ; X Jp " ■■ . >■ S-; "<■' ,i T. B' r .’. V- , 5 c ' '■y *u *4 - r ! 'f' •>" ', / ’ ■(?• n,A^j V / ■.’*' ■'. ., ;V.,* ' ■ ■ ■' ■ ’ — ■;^:3 ^ ■ ■ ■ -ms: . :.^.vfe»f’:-vli« * > \ L.1 m ;?.t;V*,' :,(»,♦ ;',’i SANITARY ASPECTS OF MILK I. Introduction Since milk ie one of the best mediums in which bacteria may grow and develop, the sanitary aspects of milk are of prime importance. The normal course of milk generally brings many different types of organisms in con- tact with it. It has been the aim of the writer to bring together data showing the sources from which these organisms may gain entrance into the milk. Of the organisms entering milk those to be feared are the pathogens. In outbreaks of disease, milk is one of the first sources to be investi- gated. Too great stress is often laid on milk as t?ie spreader of disease. Some of the various diseases spread through milk will be discussed and also milk in relation to infant mortality. Pasteurization has been found to be an efficient and cheap method for eliminating disease organisms found in milk. II. General Milk Contamination. Udder. In the early days milk was thought to be sterile when drawn from the udder of the cow. Russel malces the following statement: — "it has been proven many times by experiments that milk from healthy animals when secreted in the milk gland in the udder is absolutely germ free.” It is a common belief now that milk as it is secreted in the udder of normal healthy cows is sterile. Infection may readily occur in the udder. T^ard ( examined the udders of nineteen milch cows from five differ- ent dairies. He found that all the udders harbored bacteria throughout their whole extent. The udder is so constructed anatomically that bacteria may readily 5 enter it. Hastings and Hoffman‘S (^907) report a bacteriological examina- tion of the milk from the various quarters of an animal with a leaking hind quarter. All the quarters seemed to have the similar bacterial count and the count of the leaking quarter was no larger than that of the other quarters. The numbers of bacteria found in freshly drawn milk seem to '^ary greatly. Hastings and Hoffman (^9'^7) seem to think that 1000 bacteria per cubic centimeter is not exceeded in the average germ count as drawn from tne udders of healthy cows. Harding and Wilson^ (191^) i:i en exam- ination of 1250 samples of milk direct from the udders of seventy-eight cows found an average count of ^28 bacteria per cubic centimeter. They found the bacteria to be about three times as nuiaerous per cubic centi- meter in the back quarters as in the front quarters. Also that the age 5 of the cow and the period of lactation exerted no marked influence upon the germ content of the udder. The fore milk was found to contain more bacteria than milk taken near the middle of the milking. Milk drawn toward the end of the period was found to contain relatively few bacteria. Bacteria may gain entrance to the milk from two sources. From the ducts of the teat they may easily enter. They may also gain entrance from the udder. Probably many forms that enter the udder find an environment unsuitable for their existence and are probably killed oat. This would tend to exe^'t a selective action upon the types of organisms i^ich may thrive there. Hastings and Hoffman^ found an organism which they described as a Streptococcus similar to Strept pyogenes in morphology and biochemical relations. They found that ninety percent of the udder bacteria were com- prised of this organism. In tuberculous udders the tuberculosis germ gets into the milk. Coiin^ (I9I0) states that cocci forms come mostly from the milk ducts. Harding and Conn^ (19^5) found the udder flora to be charac- terized by a lack of motility, of spore formation and of gas formation. They found them to be composed of gram positive organisms and mostly of micrococci. Evans^ ( 19^'^) divided the udder bacteria into three groups; strepto- cocci, micrococci, and bacilli. She differentiated between the long chain streptococci, which may be of a vljulent type and the saprophytic Str. lacticus (Kruse). She was able to isolate Str. lacticus only once out of 192 samples studied. She concluded from this that Str. lacticus does not localize and mviltiply in the udder. She found micrococci to occur most frequently in the udder, isolating them from 11^ out of I92 samples. The majority of staphylococci of the udder she found to be nonvlrulent. She ! h isolated s bacilli related to 3 . abortus. Moore^ (.^9^^) states that the species vary according to the care and environ-^ent of the cow. In normal cows of good health the udder bacterial flora seems to be g of little significance. In cases of disease this would not hold. Colwell (I9I7) bas shown that cows infected with mamraitis produce milk with a very high bacterial count. He found that in every instance where by physical examination one quarter was known to be infected, one or more of the appar- ently healthy quarters proved to be infected with similar organisms. This shows that even though milk from the infected quarter be discarded, the other quarters v/ould raise the bacterial count of milk. In practically all of the investigations made, very few instances have been reported where organisms of high virulence or pathogenic have been isolated from milk aseptic ally taken fromthe udders of healthy animals. Utensils. It has been known for a long time that utensils played a large part in contaminating milk ■with bacteria. Utensils v/hich are not thoroughlv w'ashed and grained form excellent quarters in w^hich bacteria may develop. 9 Stocking, Jr.' in I9O7 ma.de some studies on the various types of milk pails used. He found the covered pail to be of a distinct advantage in excluding dirt end bacteria from milk. He found that the form of cover made little difference, provided it was a device practical for use and the ares through which dirt could gain entrance to milk was reduced ns much as possible. In regard to the different strainers, the desirability of a straining devise depends upon the style used. The use of a. strainer in a pail whe’-e the dirt which fells into the opening is llkelj'^-to be driven through by succeeding streams of milk was found to be very undesirable and to in lure the keeping Vi ■* ' Nv* '■'^v wmsf. • .s» < . rf;,«i -ti'i ■>.. Jr."" -lyt'lrnff > v\* aiserjn - to f\ - .' i ' 5 •'/>'/, ^. •il-,'^.1 i.” "■ ■ il ,"■■*■■ ..**♦. «,iN * :< ;■ ’ vV , ■■-!:’ .. ■ - . ,. . ...... - ;■ , T ■ > vf f- vp,. ; .<•! , i»; . ii ?.^.v5f ’'-'^ /% Sir- ' ■"; V ' . ;' •■• ' into /..■‘•j.-; • . ..» ,.ik . -iw’ . I k-.'tr.if, j, n* i._* ;it rCLi/L.^? U/^y^x -*Jtt .*? n’t! 4 W’iPA ^lvl% 'fPVV^i { ■ ‘i r,. >tn.,t>fV 7K,^ • . ' ■■'. ; y •">; '•■ • ’ . ■■.,*•<»’* •' rC 'C. .■■:'<\?’*',i;.y' ' ' : ■ k «*.■ ’ »» c*^'ij#' jj/! 'iln»,''y.i w -;T»..t .;' . »!^»-;;-'i , . ... ...ai?/.^..v/ r^ .i , ^aKl <■£1- quality of the milk, ^beorbent cotton as a strainer v/as found to be a decid- ed advantage in preventing the entrance of bacteria into the milk. Prucha end others (I9IS) studied the germ content of milk as influenced by utensils. They found the utensils rather then the barn conditions to be the principal sources of bacteria in milk. Then all the utensils commonly used in handling milk were thoroughly strained, the bottled milk had uni- formily only about bacteria per cubic centimeter but as soon as strain- ing was omitted the bottled milk frequently contained several hundred thou- sand bacteria per cubic centimeter. They found the greatest contamination to come from the most complex apnaratus such as the clarifier and the bot- tle filler. They compared the following relative proportions of bacterial contamination from various utensils with the barn influences: — pails add about eleven times as many bacteria to milk as the barn influences; the strainer one and one-half times as many; the clarifier thirty times as many; the cooler ten times as many; and the bottle filler sixty times as many; mak- ing a total of 112 times as manv added by the utensils as by the barn factors. From what has been given it can be seen that the need for careful hand- ling of milk cannot be too strongly stressed. In selecting dairy utensils it should be kept in mind that they are one of the chief sources of contam- ination and only that apparatus which can best be cl aned and sterilized should be selected. One needs but only to visit some of the dairy farms to see how careless and thoughtless many fanners are in the care of the milk pails and cane. Much of this is due to ignorance on the part of the farmer but with proper instmction such as may be obtained from fann journal a and papers, this condition ought to be imnroved. r,v %- 1 ^ 1 ' ' ^ '\ ' 'vy-' ,4 \,.f : is^-. r ^.V'*' 4tiM-:^-i '^^^hAM^^ ‘-0 ■£ .^ .fulfil j A' .- ,/^*5,-'t! ' ''(’(k^i kym]' ■■• '■' >■ V V B ^ *■ ‘ic,f«> *M-} •■ A ,: ^ ■' V*- ' • '.V - ■ " ■■ ' 6 Low Temperr.tures. Ravenel and others (19^0) studied the bacterial flora of milk held at low temperatures. They found that in milks held at plus nine degrees centigrade there was a clumping of the casein and fat, no increase in the bacteria developing on agar and gelatin, and an increase in the amount of soluble nitrogen and a decrease in the acidity. They found a marked in- crease in the bacterial content of milks held at zero degrees centigrade v^ich resulted in an increase in acidity and an increase in the percentage of soluble nitbogen so that it eventually amounted to over seventy percent of the total nitrogen and a decrease in the total nitrogen content due to the liberation of free nitrogen. They found putrefactive organisms to grow well at low temperatures. There is danger of cream being held too long at low temperatures. This is due to the demand. They state that cream held for a long time at low temperatures may be normal in appearance end taste but it may contain the by-products of the putrefactive bacteria in such amounts as to render it harmful. Ice cream poisoning which is quite common was found to be due to bacterial by-products, Ravenel and others (19^9) made the following statement with regard to milk held at low temperatures: — "In practical effects cold storage is identical with pasteurization since it removes from the sphere of action that class of bacteria that prevent the growth of harmful bacteria to de- velop." They found that some organisms disappear during holding while others become acclimated to lowrer temperature of incubation. Micrococcus aurantiacus (Cohn) and micrococcus ovalis (Esoherich) v^ich belong to the acid forming group was found to be most predominant. 12 Pennington and others found that in milk a cream held at a temper- ature of zero degrees centigrade, proteolysis of the casein was primarily 7 of bocterial origin. They state that the proteolysis of lactalburain is due primarily to native enzjrmes in milk. They found that the bacterial flora and native milk enzymes by their combined action produced more rapid proteolytic changes tharx were produced by either agent alone. Also that the general trend of proteolysis by the different means mentioned in- volved a breaking down of true proteins and their passage through caseose and peptone to amino acids. The fermentation of lactose with the formation of lactic acid was claimed to be due largely if not entirely to bacterial action. The above changes (digestion of protein, fermentation of lactose and increased acidity) were found to be progressive changes and accompanied by lowering the point. The I. number and index of refraction of butter fat remained unchanged. From the foregoing it may be clearly seen that milk kept at a low temperature for a long time will contain a very large bacterial flora. This flora consisting largely of putrefactive types of microorganisms will render the milk unsafe for drinking purposes. Many of the decompo- sition products are very poisonous and toxic, though they may not always be detected by tast and odor. Little has been done in regard to studying the bacterial toxin formed at these temperatures. Barn Factors. Prucha and T7eeter^^ (^9^7) studied the barn factors as influencing the germ content of milk. The study was conducted in three dairy barns differing widely in the degree of cleanliness. Samples were taken from the milk of individual cows as the milk was brought from the barn to the milk room. The germ content of each sample was determined. The germ 'i ■* *?»> 1^ --viM-'-^^ . n i4 Vi <> 4. * .. ^ :’ •■■""' ' '-"MW '•• ■'t im ■ 'Si ■ ivi- VI ' ' 'i- / y/ ' .' ' It;'' ■*' ■■■■. " ,'V^' , ' i ,- '*i ^l^jFVy _'**■,•*' ’ ‘’‘‘.■'•'f'. *1' ' •*'■■ *' '•:>)■■:'" y"''' '’•* ,i‘i' ' 'wWr^ tv, V-' '■hJ y MttJVVgpV'w..-*'*, x4 ’^•y> ': ■'-' ■ '■ ''' ^',-:Wv' -^''.'v'* 'V' « -t • ,v„»^ . • •■. : ■*;*'• . 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'f*4' *k1v .'fcitfi W^>< t V ' ■ •.'^’%«r . .. , '■■■■:'■■'?- ■'•• /'>.■ ^'yassA 1^' hit (f'.C Ml iiiJSMiiiHLliii ' .k j ‘^i. 1 ,.7 .^.rv.V , K.’ir yy fu A/-*- .till *-« Ik', rS y rf-.. f. f» '^1 P >'•'/ V Jf* r *-** M,'*' '^ 9 ' 'i .V'SRr'''f^ i (♦\:^'»,'l 'ijSf^i- ^f\0^ .i>4.v'v a ■"■ - ■ •- .te^riS:' y. . •.„ ■ " ,i. Ji.'^ T! it.'W,'ihit„'<' . ' •.-., w. i^Sn mKS^^/A.t y Afi ^ ■/ c ^.vwwlte ^ ”■ ^ . .; ^ ..■' hr! .. . '.-.^-.A.'. i.JsaKsfe: v,>HE," : ' iiMti.. vr;^ »9. 11 Bibliography. 1 Russel, H.L. ; The Sources of Bacterial Infection and the Relation of the Same to the Keeping Quality of Milk. Univ. Tis. Agr, Exp. Sta. 11th Ann. Rpt.j 1^0 (189^). 2 Ward, A.R.j The Invasion of the Udder by Bacteria. Cornell Univ. Agr. Exp. Sta. Bui. 178 (IPOO). 5 Hastings, E.G. end Hoffmann,C.; Bacterial Content of Milk of Individual Animals. Wis. Agr. Exp. Sta. Research Bui. 6 pp. 1£9- ^907) 4 Harding, H.A. and Wilson, J.K.j A Study of the Udder Flora of Cows. Tech. Bui. No. 27 N.Y. Agr. Exp. Sta. (March 19^5) • 5 Conn, H.W. j Practical Dairy Bacteriology. Orange Judd Co.(l9l0) pp.59* 6 Evans, Alice C.; Bacteria of Milk Freshly Drawn from Normal Udder. Jour. Inf. Diseases 18:457> ( 19 • 7 Moore, V.A.; The Normal Bacterial Invasion 5f Cow’s Udder. Principles of Microbiology. Macmillan Co. (19^^) 8 Colwell, R.C . ; Inf luence of Gargety and High Count Cows on the Number of Bacteria in Milk. Abst. Bact. 1:^8 (19^7). 9 Stocking Jr. W.A.j Comparative Studies with Covered Milk Pails. Storrs Agr. Exp. Sta. Bui. No.'^8(May 1907). 10 Prucha,M. J. jWeeter,H.M. and Chambers, W.H. Germ Content of Milk (As Influenced by Utensils) U. of 111. Agr. Exp. Sta. Bui. No. 204 Feb. ( I 9 I 6 ). 11 Ravenel, M.P.; Hastings, E.G. and Hammer, B.W. j The Bacterial Flora of Milk Held at Low Temperatures. Journ. Inf. Diseases. Vol.7s (I 9 I 0 ). 12 Penington,M.E; Hepburn, J.S. ; St . John, E.Q. ;Witmer, E; Stafford, M.0.;and Burrel,J.I. Journal of Bio-Chem. .Bacterial and Enzymatic Changes in Milk and Cream at O^C. 15 Prucha, M.J. and Weeter, K.M, ; Germ Coritent • of "Milk (As 'Influenced by Factors at the Barn). U. of 111. Agr. Exp. Sta. Bui. No. 1p9 May ( 1917 ). 14 stocking, Jr., W. A.j Quality of Milk Affected by Coromon Doirj'’ Practices. Storrs Agr. Exp. Sta. Bui. No. 42., June, I 9 O 6 . 1 5 Harding, H. A.; The Effect of Certain Dairy Operations Upon the Germ Content of Milk. (H. A. Harding, G. L. Ruehle, J. K. Wilson, and G. A. Smith) N. Y. Agr. Exp. Sta. Bui. 565:197> I 9 I 5 . w ym^^i mmm BKf r-y ,. >x[ , sr**' ■V, v^V ■„; .-i ., < WJK. 1 ’’ ' y I > • I. ' ^ V T • ' , .' ' ^ ^ .'. »' .VA-, i. • * ' • ', . • '^'Jv •aiii^i ,i4»‘(-»*^>?tF 'o'^f \iilTO .Vj{ .W -■ A-Ar‘> :■ ' »/.y/'yyyvyi.!V . \ •“■ ■ ■/ y ■- ^>^*' "' • .r,>r ,-%f ;*!■- tiaoo ,i.'r^ff . ■. • A v;-A -A • ' ■ . ,• t' N . ’ ’ ' 4^ ' jr y •■^ .*..• k'f tM ,\k i.kjPu^x ^ 1,.* '.r .-.tT. .lAfk’-aoM'VS* . '■ :1 fa &siigjg: .c ' ■’, ji, ) ’■■,.»■'. ' i' ''i,^' ' 1 ^ lift . _Jk ''H /^ 45 12 16 North, Charles E.j The Dairyman Versus the Dairy. Am. Joum. Pub. Health, 50 19-525 19 15- 17 Bergey, D. H.; M. D.; An Investigation on the Value of Certain Sanitary and other Precautionary Measures Upon the Bacterial Content of Milk. Penn. Dept, of Agr. Pep, Part I, p. 155- 165 1900 . 18 Esten, M. , and Mason, C. J. ; Sources of Bacteria in Milk. Storrs Agr. Exp. Sta. Bui. No. 5 I 65 -IO 7 1907-19^9 15 III Epideraiology of Milk being an excellent medium for bacterial g’"owth has been one of the first sources to be investigated in epidemics of various kinds, Sorae of the diseases of human origin carried through milk as a medium are — diptheria, Asiatic cholera, diarrhea, ( shiga and flexner) typhoid and paratyphoid fever, scarlet fever, tuberculosis, septic sore throats and others. Many of the pathogenic organisms gain entrance into the milk f lo m the milker or utensils. Many such cases have been observed especially with Typhoid. A typhoid "carrier" can very easily contaminate a wiiole milk suppler. Such cases have been amply demonstrated from time to time. Diptheria. Diptheria is a disease caused by B. Diptheria. It is spread chiefly through secretions from the mouth and nose. It could readily be' spread by the handling of milk by one who is affected with it. In an investiga- tion carried on in Massachusetts by Kelly^ (191^)* diptheria transmission through raw milk was found to be of so rare occurrence that it was con- sidered negligible. In a study of twenty-eight instances diptheria existed at the farm or dairy arid in ten instances the disease was attributed directly to the cows having garget, chapoed and ulcerative affections of the teats and udder. Asiatic- Cholera, The organism Sp. cholerae was found to be the cause of Asiatic cholera. The organism is discharged in the feces of the sick and of the carriers. From this source it can be readily spread by flies, by carelessness on the >-Y :n.' ^^’- '“'> ' '■■ ■;>' ir -^r.^ ^ - '■ -WlSi ■ > '• kI1'v®’’''s.’ ' ■ ' ' ■'‘'^M''>c t^*)^’i^«!‘^' ; J'lr /•/'•» '.■ ••>■ ■ . •' ' . •■ • •'.■ V :• , , ■•i.'' , ■• ^ •■.’ ■' .^'V/‘r: 4 ' . ' ,v‘J , I ‘ A iiii"’ i' i 3 ' 4 fO f .;'“f.n' ■ ■ -’ y t •* V , r ' ... ‘^ _■ ' '' »vv, / tPtV > ■■ , >ii^-l4 l4, * ” * . , ,N..: ^ ,’ X. , Jf';.,, viv' ': "'1^^ Si ''' ■ . , '. .'•';4 »\,i^!>. % ■ ■• ';■■^'^'^.*^'^.4;•i^•‘^>^ E'li*' ' M,... a I'w-f* n.» air-i ^ .- j. ,tJJi.tiL.\i •' .. »' '4‘ .ailS '#.' 1A part of the one affected and in innumerable other ways. The vibrio requires a neutral or slightly alkaline mediuim for growth and perhaps for this reason milk does not serve as a very effective carrier. Milk apparently is not a very important agent in spreading this disease. Typhoid Fearer. Typhoid fever is one of our common diseases. The typhoid germ is discharged in the feces and from this source it can readily be spread. In outbreaks of typhoid fever often the milk is blamed and unduly so. Kelly ^ ( I 9 I 0 ) in a statistical study of milk-borne infections finds that only 5 per cent of the total cases of typhoid reported can be attributed to milk. This figure does not check popular statements which place it at a much higher lesrel. p Busey and Kober ( 19^9) in n study of 1^6 epidemics traceable to a specific pollution of the milk find that in I 09 instances there is evidence having prevailed on the farm or dairy. In 5^ epidemics the germs reached the milk by soakage into well water with which the utensils were washed. In instances milk dilution with polluted water was admitted. Scarlet Fever. Many attempts have been made to locate the causal organism for scarlet fever. As yet the causal organism has not been definitely proved. The trs-nsmission of scarlet fever through milk as a mediam has been found to assume little importance. The per centage of cases that can be traced to milk has been found to be very small. As constrasted to diptheria the percentage ofscsrlet fever cases traceable to milk is the larger. p Busey and Kober (I 9 O 9 ) in a study of 7^- epidemics spread through the medium of milk find that in instances that the disease prevailed either 15 at the farm or dairy. In 6 inatancea persona connected with the dairy either lodged in or visited infected houses. Tuberculosis. Tuberculosis is one of the common and worst menances with which sanitarians have to deal. A vast amount of money and time hss been expended m in investigating this phase of the subject. Milk has long been known to be one of the chief carriers of tuberculosis. Adults possess a great deal more resistance to bovine tuberculosis than do children. Anderson^{ I909) in an investigation of 225 samples of milk found that 15 of them or 6,72 percent contained sufficient tuberculosis organisms', to cause the typical tuberculosis symptoms in the animals inoculated. 11 percent of the dairies which he examined contained tuberculosis virulent for guinea pigs. Practically none of the pulmonary tuberculosis is due to bovine bacteria. Tuberculosis seems to run in rather definite stages. The pro- dromal stage being the stage in which incubation occurs. This stage is followed by a period of sickness. Prom this stage either death will occur or there will be a period of recovery. Long^^(l92l) reports a very interesting case. Robert Goben of Edgar County, Illinois had his cattle tested for tuberculosis end one of the covfs reacted to the tuberculin test. He did not believe in the tuberculin test and later took the condemned tag out of the animals ear. The cow looked healthy and he told his men there was nothing the matter with her. He talked so much that one of his tenants Jas. Kelly was induced to take her in payment for work he had done for Goben. Kelly used her for a family cow. In Kelly’s family there were seven children. In the spring some of the > V ft '‘if- \ I t \ ' I i % 'v I < ■ t \ i ! f ( i i 'i K i "s i 16 children commenced to complain and were sickly. A Doctor was consulted and five of the children were found to have tuberculosis. Tlie youngi^st child was still nursing and the older child was not allowed to have any of the milk as it vms thought better to give it to the younger children. The five children affected were sent to a tuberculosis ©anitarium v&iere they will be properly cared for. It is thought that one of the children will die. Goben was fined one hundred and fifty dollars for selling a tuberculous animal. The cow when killed and posted shov/ed generalized tuberculosis. Great effort has been made in the past few years to clean up the tuberculosis scourge. The discovery of tuberculin has played a large part in making this possible. Tuberculin was discovered by Koch in I89O. It is a glycerinated broth culture of tuberculosis organisms where the organisms have been killed and filtered off. This may be given in various ways. Ninety-eight percent of the positive reactors to this test show lesions on autopsying while eighty-five percent of the non-reactors show no lesions. If this test were made compulsory a greater advancement toward cleaning up tuberculosis could be made. Septic Sore Throat. Septic sore throat is caused by the Smith streptococcus. Milk afford an excellent mediam in which it may develop. The disease is character- ized by a sudden onset, high and irregular fever, inflammation of the fauces, marked enlargement of the cervical glands, particularly in the case of children. The course is much longer and the symptoms more severe than in tonsillitis. The joints are often affected and often the heart and kidneys are seriously damaged; middle ear disease and erysipelas •i ■ 'O' -V . ' ' , '■' . ♦V'-'v ., ,,'' ';• . '■'* '■ ''2^ . ' : .<^ -W- 1 , ■ t ', ;’ ’•■ ■■» '■ Vric, ^'^•^U'.- ’'W ’ ' '-f ' 1 ; Ktv ■ ^ ‘"t kv h ‘Jh;' » ■'i' »' ■ ■ .' ■ -^ If**' ' .'•"’.‘O'''',. . ■•'' .' . ■■ * A*-'’'* ‘ -v ’.*■■' , * • ' „ta, ;:^ ; ./I, ,,; tfi , ■ ,i i-^-'-'iSiW j 4 -■ ' ;r V'''> »- I; wV- >;. ■■w.vM :v*.a r • < . ,5^- i*'v • ^^1 ' .-t 3. . ’^.J t\W*' '"^ -*- ' -W » rT r; .Vi' 17 sonietimeB result, pneumonis nnd peritonitis ’nay develop and terminate CZ fatally. The above symptoms have been described by Parker'^( 17) • Septic sore throat seems fortunately, to be relatively rare. It nearly always occurs in epidemic form and is of more serious consequences. Streptococci . Streptococci seem to thrive very well in milk. Various types of streptococci are found to be present in apparently normal udders. The big difficulty arises when we try to separate the pathogenic from the non pathogenic or harmless types. ’.louth cultures from cows were found to ferment dextrose, saccharose, lactose, mannite and frequently raffinose, but were almost without effect on starch or glycerine. Udder cultures were characterized by general lack of f ermentati■■ ’ ■■ -aiM ■!;. IT- •Jv ■ .V •-:'' '■•«■¥'( ’ .>: 'J.Jm^::m:.^^i^Hi. V::& JfLL}m:^ . rr- --’ ^ '."' 'V 1. ' i. ;’.-4' '. • 4>- ' :,/ * .* - ' ■ . ■ •■■■■' > » >'iyys ikiklv^A. -A':: i^'|:»'.’* ^ ■ V-'-. ? 'vJi^, ^ '77- ,, {Ji® rf '^>1. .;V’'‘^ ;’ ik. . . *. -3. "V * » “Lt » JP •_ . . . •ii.'i. w7 '.> rw,.. /. -i A fi/irasr-'aicsi 21 deaths were in families with an income of fifteen dollars or less per week. They found that about sixty percent of the deaths from the sammer gastro- intestinal disturbances were in children who were admitted to the stations during July, August and September. Diarrheal Diseases. Diarrhea seems to be quite a common and prevalent disease among infante. The disease seems to get a better foothold in the siumner during the hottest months. It has been noted that along with a high bacterial count in milk that diarrhea’s were more common. Children who are not up to physical standard or are congenitally weak are very susceptible. It has been especially noted that babies from two to xour months of age especially those that have been recently weaned seem to be the most susceptible to the disease. The humidity has been founa to be a big factor in the diarrheas.. Carbohydrate fermentation was fo'und to play an important part in many of the diarrheas. A formula low in sugar is recommended for treatment. Hill (lolo) in a study of diarrheas, of infants gives three types of diarrhea; mechanical diarrhea, due to mechanical irritation, fermentative diarrhea, due to chemical irritation and infectious diarrhea, due to bac- terial infection. The mechanical diarrhea was found to be most common in children over one year of age. Paw fruits often cause it. The fermentative diarrhea was found to be m®re co.mmon to children under one year of age. It was said to be caused from the following;- too high sugar content in feed, parental infections, overheating, nervous exhaustion and excite- ment and constitutional weaknesses. 22 Bibliography 1 Taylor, ?.E. and Van Ingen, ?. M.D.; Infant Mortality and Milk Stations. New York Milk Committee (19^2). 2 Price, Win. H. M.C.; Some Statistics Regarding Infant Mortality, ^rd Annual Report of the International Assoc, of Dairy Milk Inspectors, pp. 95- J Helraholz, H.F. and Hoffmann, W. M.D.j An Analysis of the Mortality for 19^5 in the Infant Welfare Stations of Chicago. Am. Medical Journal (19^6) :6j p'^rt 2 pp. A Hill, Lewis Webb M.D.j The Etiology and Treatment of Diarrheal Diseases of Infants. Journal Am. Med. Assoc. 72:16^^, (^9^9)* Conn, H.W.j Diarrheal Diseases. Practical Dairy Bacteriology. Orange Judd Co. C 1910). Grover, J.I. M.D.j A Study of the Diarrheas in Boston for 19^5* Am. Med. Assoc. Journal Vol.;67 part 2 pp. 1^62-1^67 (l9^o)* 25 V. Lectio Acid Becteria. The curdling and souring of milk is a phenomona which hes been known for ages but not until within comparatively recent years has the cause for this been understood, Esten^(l69^) isolated forty seven organisms from milk. He thought them all to be identical. He examined milk from thirty widely separated localities and found with t\vo exceptions the same organism to be present. This fact led him to believe that one organism universally existed, in the territory he studied which caused the ordinary curdling and souring of milk. The organism isolated he found to be identical with the organism isolated by Gunther and Thierfielder who concluded that their organism was the same as Lister's Bacterium lactis and Hueppe's Bacillus acidi lactici . Conn and Esten~( I 90 A) found the following phases to be present in milk:- Lag phase or period at the beginning where there is no increase in bacteria. In this phase some species meeting with an unfavorable environ- ment die aut. The length of such a period depending upon the temperature. After the preliminary period, c period or phase of rapid multiplication of bacteria in the milk then follows. The temperature seems to govern the types that develop. In the next phase other forms of bacteria other than Sihe lactic acid flora seem to be killed out. This is probably due to the acid. About ^0 per cent of the flore then present is made up of the lactic acid type. The aerogenee type of lactic acid bacteria which are the gas producers seem to be favored by a temperature of 57 degrees centigrade. The aerogenes type is an enemy to the butter end cheese maker. 2h The curdling point of milk was found to be independent of the number of bacteria present. Milk was found to curdle under different donditions when having a bacterial count as low as 8,000,000 per C.C. On the other hand a count as high as 4,000,000,000 bacterir per C.C. has been obtained before milk would curdle. Various reasons which are still unsettled have been given to explain this phenomona. A great deal of confusion arose in the past in regard to the morphology of the lactic acid organism. It was known by a good many of the early investigators as Bact. lactis acidi. Kruse'Cent. f. Bac. u. Par. I. , XXXIV, P757f 1905 ) J'nd Heinemann (Cent. f. Bac. u Par. II., XVI, p.558, I 9 O 6 ) insisted that there was no such a thing as Bact. lactis acidi and that all of the organisms which had been so named were cocci which should be called Streptococcus lacticus. Conn and Esten^( I 9 O 6 ) preferred classifying the organisms separately. Esten'^^( I 9 O 9 ) isolated the Strep, lacticus from corn plants and quite frequently from the mouths of cattle. He concluded that the cow’s mouth was evidently the most abundant source of the organism so far as cow’s milk was concerned. The lactic acid organism is a very beneficial organism as far as man and milk are concerned. It is very important in giving the proper flavoring to butter and cheese. It also is of importance in that it inhibits types of bacteria which are pathogenic or otherwise undesirable from gaining much headway in milk. It is an organism that is apparently not pathogenic for man. According to Metchnikof f ’ s theory, which was later proven untrue, it is beneficial when in the intestinal tract of man as it inhibits other undesirable forme from developing. •a ,. !•; E^t'^ ■ : ■*• , '.>, ,*V' tr .t ■ ‘•■ **^ . . ^ . ,' 1 «>q, . ^ ^ V' 5(^1 'll .V ''’’I'' 4 ■ a'" ',•? ■ a™-’ ,jr ’ * ' ■ *i> _ ,,*.>■.• '/HHUt.;' \.v.' *■ k, 'M :s,f i..'T . 1 -^ . .i,sBt_ -,T- «W , v" It/* .’;-» *u^i -I'O*! .J--»a «< .'!t»iji' W-«jiu>’ 5 ^'i/ ..« :. Ij '' •f'»;^t , ■ V . .. ^ ^ * f -' ' vvao,: • ! '*' .„*■' • ,4'. ‘ft ^tniuW» j Ij '.>-■* 'f Hi ;'f V'f . taft.4> !| tO< 4* ■ '^■y. ■ ^ » Ti r^*«* r’-** ■ (*" ■'i #(fl to "♦'|'Mi9% '*C I»/d» w \ ^-i- - p, t iVk ..#»*-» '“;m . f\ Tl Ajf < . ' ■ A4 ■ ■*'' -'a' .;'''’ '■ ■ . -^ '.'* ■ ^ ■ '.^' ■ '• # F ' J ■'V.. ’ ; , ,, V" - ■ 1. ' 'J^\"miM O - H .fll'i lil vl*i|'ii ,( -.'i , Tf«-> ■ - '>■' V'i&'j i|| y. j *' -I -'^».' l/X' •', '> I '1 ,. ■ ' «,'.> ^ V, » •'■" y •, -^ 7 »' ’ ° ^Vl'' ^ • '■■ ■ ‘ ''V i.- r' T '. 'i •A /Ja f * ,t.2 .p *»■; Hi;. //' ; , jjr^ ^ i.S»f' • '■ ’■ '^' ' '^' '< t,'- '’>1 V' v' ^'r■ ■' ' '.-■ . ‘ ii- . ■ ' ,.T^' 25 Bibliography 1 Eaten, Bacteria in the Dairy. XII Bacillus Acidi Lactici and other Acid Organiaraa Found In American Dairies. 9th Annual Rpt. of the Storrs Agr. Exp. Sta. ( I896) 2 Conn,H.^. and Eaten, ; The Effect of Different Temperatures in Determining the Species of Bacteria which Grow in Milk. Storrs Agr. Exp. Sta. I6th Annual Rpt. p Conn, H.W. and Esten, ^.M. ; Classif icration of Dairy Bacteria. Strept. lacticus. Storrs Agr. Exp. Sta. Rpt. for I9O0 pp. 9^-205 E. s.R. vol.ie p. 979. A Esten, '17. M. ; Bacterium Lactis Acidi end Its Sources. Storrs Agr. Exp. Sta. Bui. No. 59 ^9^9 Rogers, Lore A. and Davis, Brooke J. ; Methods of Classifying the Lactic- Acid Bacteria. U.S. Dept, of Agr. Bureau of An. Industry Bui. 15^1 f 1912) '■'W v--.*.^M 4 ;:rX vT»'J^ 4 ' %i^,r ^ |H^^P^v w^‘ V ‘ ;ji:*afl > *r* n2 J>Jii/n]B .i^iiw ' gn “* ^ ’. ^ • ., C/ \.Vjp®fljB|f . • ..>U' J tipiife^ a • **^ «i^.l w«^:«nU ';. «-« ^'< I ' ’'f f •J«?j iaIinAi 4ifc^t - '■■gt’f'- «,T^A>un4tV^y H' ' [ .• V ' ': ' " i ?;' v --''1 ( ■- . ■. -**A>** lu' '■» . It . ^'V‘ ;*'«t, i 41 ' V; jju*r^^ .<.*!tVA''. .'i''»^liv£5 <>^'vWii..<8^; i' .*'! ,1h<. ^h»i'a5 . ' i r£^ L '1 ■ ‘ ■ ■ %''*4 ■ ' 4 . J' ■ I ,Jw - 0 X 4 'S :jx li' %ifQ^Jhy ,i*^fl'‘ ■ 5 v “ ■?.,-4 ' ^ ■v t. ,■■*■■■ i .f ' bevfiyniP -^' ' ;'i /’ VV' <^/lr ^- . #V’ v," 5 *\"lp 1 T ‘ ■' ''>'*' J.' ’ *■'* ■ ' ' 'i>. ■ ■,■•', I ■ ■ : f j. ' '. .’* ' '* • >•■ f’ v» wtW 'W' ■ .;• « •' •,' ■ '' ,*V ' ^\''..V.^,.,^ -f - » V'^ ^ ■ •'' ’ 1 *^' ': ;-^ * if' i ■^'. ' ■ 4 ’ ,• \A ' /;. -■ '■£ I >. • >^V-’ . ' • .\^ • , W;' ,*■ k&t'. 4 !.. ' ‘ ' . '<'.''»M^l -* |> 'ji^'‘''fl 26 VI Milk PaeteurizBtion. Pasteurization is now known universally. Much has been written and a great deal of woric has been done on this subject. Pasteur (1879) was one of the early workers in this field. A great deal of hie work was done on liquors. The following statement was made by Pasteur V 1679) "Our proposition concerning the causes of the disease of wort and beer might be demonstrated in several ways. The following is the simplest;- "Take a few bottles of sound beer Place some of these bottles in a hot water bath and raise the temperature to about 60 degrees centigrade ( 140 degrees P.). Permit them to cool and then place them by the side of the other bottles that have not been heated. In every case especially if we conduct this experiment in the summer, we shall find in a few weeks, the length of time varying with the temperature and quality of the beer, all bottles which have not been heated have become diseased, in some cases even to the extent of becoming undrinkable ." The term "pasteurization" was first used in recognition of Pasteur's discoveries on the causes of the deterioration of fennented liquors and the means of preserving such liquors by the application of heat. Later the term was given wider significance and applied to milk. Koplik^( I 89 I ) made the following statement:- "As intimated it would be ideal to sterilize milk in small or large quantities at the dairies, but this has never yet been attempted in this city." Pasteurization today is now used in most of the larger cities in this country. The temperatures first used in the pasteurization of milk were around 155 degrees P, for a period of 15-20 minutes. Heating milk above 1^0 degrees P. was fo'ond to change the physical conditions of the fat globules and the p‘; •" «sSW 34 l Y T "'7''f' V\t-^ i.«' ^ - .'■ yJki .a«Uf alurnttifi iifjl tr liO/Sw i' ': i' HHM ^ . '•■■■ 'jt «i 7 ... ^ iR-- * >4.4Vt ■ V ' '■ '"' ' ' " •-' ‘/if,t~ j 44 nfrf i * fjoirv i* '■» *■'? ^ ; ,'• ‘ ' *'■ v'/ •' ;* " -»''Aji- -j ’■*' ^;i; V l?t' .* «ft ft -iH ' 'I' ■ : ■ .♦tails’ lsfy» >t^ .. '.I ^ ' .' - * II . ii'i I.’ - I .•! ' i*iir •’ If' .' V, . , _ -'i i-’Hjt ;$p‘:tty »A /iJ iif M ijSr* n fll '^1^ "tio NIWU^ ' I^HSril ' *'' V liV ’ ^ ' Ct ' *1 ' V A ■ *t'"Ti '!?ii H itJj ‘»c»i tu> »fel» piJ mUt^ k ouJoJ’sroMt] j'/ r>H ^ 4'?'■ ■.•.••...’».'f- V .'!'•■ ^**’5 I -ys-j rA '* nX JtfUl, X'^f«4d,,#r ' ■;ii .'■ VI I ■4. ' ■>*3 ■ -V ■ ’~ v' .-■i ■■♦ a^XMcvi IT' ,ih-«i'o M4 •■ -*■ ■' *'• ■■-.• • ~'..l , - 'j:,- 1i ./^-iPSpBL lo'J. •«.'*> O'J i{l*v-o »4^ypy.i -^^'’■■«4»tiii»'5»»iOt^i ■«VAa'' ■V* ’^'1^ ’..-»■*' ;ifLiti^(MHX ' '■ E'' .,v ''’'^ ’■■- ,.i ' -’ *■■ ’■■ ^ ,;■ v/,'.. . •' ,' tJ4: i.'* .’* 'i ^'i' - f .*^i«S'’'*%iL3' ' ,!2c ^ojU! fti f»«r . «,i • •• . 'i>-i'.. . .'•.’■i ',' '‘•j ■isfit) t^'i'dVfUS *‘J ^Hv* ,’%t W».4‘|'e i ' « •. • ' ■ ■■ . '■'f' ' ''fir* '.' id • ■ VJI, ■' ' A A. <$iU , . Jr’irt n-i>l If? ■*■••. ■■' ■ •' “’•■ vVi‘. ^ -T ’* <'r Ife. U^.- • * ■M-.' , h* . } ivi'; • Pii ‘\9' Uo4,«X), **iU-^E**^^ ■ ' ..■■■■' " « :,(i ■’"■• ' vi" “' ''. ■^V■'4•'.A , ■ • ■ • . ' ' (1* ■ '■ I, " *i'''. ,’■ 4.1/ "'A ■i'f'V.ikA' '<.H9 E^v;iy ,' vv-‘M>'., a ■•* 3. Wm if. 27 cream loses its property of rapid creaming. A temperature of 1^0 degrees F. was found to kill out the vegetative forms in 20 minutes. The proper amount of heating has been determined in many cases from the resistance or thermal death point of tubercle bacilli. A temperature and time sufficient to kill out tubercle bacilli is much desired. A temperature of 60 degrees centigrade (1^0 degrees F.) for 15-20 minutes was found to kill tubercle bacilli when they were suspended in distilled water, physiological salt solution, bouillon and milk. The tubercle bacilli in the pellicle of milk which foms upon sterilization were found to live at least as long as 60 minutes at 60 degrees centigrade. In later types of pasteurizers, pellicle growth did not form as the milk was heated in closed containers. Preventing the formation of the pellicle in the milk upon heating thus was a great stride in making pasteurization more effect- ive. The effect of higher temperature exposures for a shorter period of time was tried . (Closed containers being used). Heating to a temperature of 160 degrees F. for a period of one minute was found sufficient to destroy the virulence of bovine tubercle cultures so that the disease was not produced in experimental animals, such as guinea pigs when inoculated with cultures ranging from 2-5 mgrs. Rogers^( I905) found that milk held at 10 degrees centigrade was in good condition from a bacteriological standpoint 48 hours after pasteur- ization. The same milk held at 20 degrees centigrade for 24 hours he considered not a safe food. He found a large number of peptonizing bacteria developing in pasteurized milk. The same phenomena was observed in raw milk and especially in raw milk held at lower temperatures. In raw milk kept at 7 ;. fir.; • -•»■" ^jgBu ■■’? r. :''i«r>Ti»' ■' jtc!#< '■%>> O-l Mg^ y ^ ‘, j > ;•■ ■'-:/■• iV ,• ■ ' , ‘ ’■ i ‘j- ■ ■ •*'' * 4 > ^v'- 'V i.v TiHL - P ,. ^ , ■ . ' ■ : ' r. P'.s R- - *- . p’ •■‘^■, . - Wi,i.l ‘ ( I '- ' ■ A , -.1 ,*'IIiV V ’ . ^ V’ ' '"■ ■'■' V '" ^ -« • *j i., ■ ' *’» •'-JPU. T. .• i V * • * ■ .. ;.. ';■■ . ,4 '*’>»*? 3ir JttlJ ' '^■' - >’''A " V//’ ,• »»i'.^i,* .^riJJwi't' fi} t)ohr-..''^iua o-- vvt' '^‘ W • . ' ■ -• if, * ff- ^ . ■ ■■ • • ■ .v"'': ,, . W" i ■* '■or. ,)'JW ^,.4‘Vft .*<'7, J i» \t,i 4a rrjv'! M^iiA fi.T' ikhfvQi ^ ( )• . 'y^ IK ;'. 1 J rt •.... V/. ■4). •■_■' ' • ' ' ' ‘" «' ' / ^ /.I.A '■ 'Ij ’’■' 7 * ■ i'- •'• . •^•rSr' .■ '*' ^ ^ 7 i y^' " • n Ot' 1 . 1 » * 'M y • I • ' ■’ ‘ • I • i«- 4 > .. ♦* i ^ ,|»' ji ‘ M ‘ ‘ ■ ' ■>> i'-*; \ .V‘‘.v ■ .'il '-,■; .^K' , '^TWirt k o* - fU.r.gt.i f T r ■' ’ ^ ':^ .p , '/'-Til ■ 'Si%S' /■•.»’ I '^As: “ii ' ' ' - . ' ^:i\.<', -«» >''i-*"/'»r/;^*" ‘ VT ■ i ^ 4 lui,^ y A ^ 1 c: ., ' -S;,. : li«';.:5;'"'ite ■ ' ■ n I ' k ' .. V. '-‘^v . , \'^‘4r^_ ' - .>:'■ miIabAmm <>^P frikrJikdfk _aK^>.A4atf Ah A y » t 4 ^ ^ - J U *♦ ' • WJ _T 4 ,f 1 fli ^ -t, 4 U 0 /f ' V ■ Ti . ■'. ■•> ► ii 9 ; ’ 4 ki< ih.trc/’ Af ** ' ' • -V^-»' 1 ' ' ' ' ' ‘*'' i ,.,; ^ i 4 T-t> ,'-o 9 i« 1 :'; V wfcvi,<# «t' i;,i{ j ■:, .•; ■ Sfe . ■^' ..is: ■ ' ’k'"?:, :*.n/^- i* i**i/ v' , ■ 'v ‘ ' ■: . ■ . • y X <)-‘V ,>1 '■■ I ’ ’ '''= )#A ', .*c41 i'lKyim el' .^rytaiifdir.tKi' t^.i>l 4'«''^,i'»rf®^i'J!|t *•?■ i'i; ,»• »’ >. .: V ^ t‘- L-‘J, V ■:•■»■, ..M fJi. .-^ titltfri‘u 26 room temperatures the acid developing from the lactic acid bacteria probably check the peptonizing flora and keep it from developing. Reinfection of pasteurized milk may readily occur and the infecting organisms may gain more of a foothold than they could in raw milk. Attention has been called to this by some authors and a few cases have been brought up to substantiate such a. belief. In later work the above statements have been objected to. Ayers and Johnson‘^’( I 9 IO) find that commercially pasteurized milk alv/ays sours because of the development of lactic acid bacteria, which on account of their hig}i thermal death point survive pasteurization. They find that and old taste developing in the milk is not characteristic of pasteurized milk. They find the relative proportion of the groups of peptonizing, lactic acid, andalkali or inert bacteria ie approximately the same in efficiently pasteurized milk as it is in clean raw milk. The "holder" process has been compared to the "flash" process in the pasteurization of milk. From work viiich has been done so far the holder precess is considered by many investigators to be the best. However there is another aspect to the problem and that is the matter of time and expense. In the matter of chemical changes, milk pasteurized by the holder process 62.6 degrees centigra.de (1^5° F) for thirty minutes was found to undergo no appreciable change. As the temperature increases the amount of coagulated albumin increases. Electrical pasteurizers have teen devised v/hich seem to work very effectively in killing out tubercle bacilli and otlier undesirable organ- isms. The disease producing organisms are likewise killed out. I^ilk has been fo'und to keep three or four days by such a treatment. The chem- v-M I •, t JJ» »•''! ^ • V . ' ■ ‘ . - -^^T.^/v * ■' V..‘‘ : ' ■ ""'.I / , ...... „. ^ ■ 'k -‘vf. ^ tSi^* i fft/fs:^[ 'ti' ■* ■■ t' 'll- “jpo '^IH ** V ,'•= '■<.■' ■ V- ■, .. ..Vv < ^ ^ m fc V ^ ^ ' . -* '^*'v * iVh » ^ ' J^ ' ^ ^ s • *'**^f. '» *■»• ■ ipr.'ir.t o*:X'h' f^ll^f ' .,' ' ' ' , .' '/■rf- . , , ,-. ■ . '. )- . ;‘> _ ^''’ 'r ' . 'Vi ‘-j - :. .,■ ' - r , rs'j >^' “FV T. ’ ik- ♦ .< ''.Ws.N-fAa ’• .?"»« , *t-i:*# «: %n : jiff r ‘''-I c.- . <) ') ' •: *>■ ,■• . . - ' '.I, J‘i'„ '. '. ." j, . -■ i tsi '*«- 1’ I i •*> f* ^ *! I •-• ■■-• .•. fjn * ;t > ' i^ro/X'iir.^^4 ^ ft t; f ^ ® 'V- - - .T ',- ' ,' - '*■ '■* h ,' ^ fw 'Jl ’ 'Z ■, ' 3 m ' 'I 0 « . • • "Mi' '''■•■‘Hi * "1 ' ■.■>' . -rr ii* v*i »i«/»lo< if -V. ;v ■ ‘.vr-;’ V;-":' ' , ■ '’ * ' •• '* j ''./i '.-•* ' .<" .‘' /.'■■'iS -j ‘J n1' en • ' 3 *.' -k*,/yv Jft O' I 'J-*^ ’"’i t i' ■ :-'■ ' . V-# ■ • , »V- ,(*■ ' i<^i T(U 4 ,t>-^ ' ^ * '(' . ^ V I ^ ' 1*1 ^ ' *' -vi ?•? ‘A v»*t . jr • ■'< v't*'- ■ '•/' ' V-. ’ \' A'V'. •»«nfli 'I 4V_» *i',<»4wtf‘t,*^. 4HHJ^/4,^w.^■,'i^’.V(f|4^ij^^ ^ ( OttT .1 ' «V1 . r ■•, ‘ , ■•',Y..?A' , ,. , ,W . - • . 1 ' (. .4 • U' ' . . '■ * >» '.* ^ .V V ’ Jp,, /{■; .f A' .i^», Vo’’" . ■'• . '•. -I- ■ ■/ ■ 4 '''i?Li'lS 1 } ■' V '■' ' i • ' - IK ' . A I • i> , ■■ o-T T. ' • I.* 29 ical constitution of it was found to vary little. A biorisator process of pasteurizing milk has also been worked out. By this process of heating no albumin coagulum results and the fat globules are the same as in raw milk. Vegetative bacterial forms and pathogenic germs are ell destroyed by the biorisator. A study of the germicidal action of the ultra-violet rays has been made. The ultra-violet rays produced by the Cooper-Hewitt mercury ai’c have a strong bactericidal action. This means of rendering milk safe for drinking purposes may, however, have some practical significance. Much improvement in regard to the organization and the control of pasteurization needs be made. It is very easy for a man of little or no experience or training along bacteriological lines to modify pasteuriza- tion in such a way as to lose all of the beneficial results or effects which should be derived from it. The two big factors to keep in mind are the proper time and temperature. Often the proper amount of attention is not given to these facts. Tonney5( 1^20) suggested that a ”shut-off” system be used in enforcing certain important measures in the pasteurization and handling of milk. By "shut-off" is meant a temporary suspension of permit to operate a pasteurizing plant. For the following reasons it is resorted 1. "Non-compliance with orders for abatement of inssnitaiy conditions. 2. Acceptance of milk from other shippers who have attempted to evade a "shut-off". 5* Failure to send thermo recorder cherts to the department. 4. Falsifying thermo recorder charts. 5* Failure in cose of a new plant to apply for a permit before ship- ,«; ■■■ -.r ■> :'..'^,i ',' j) .» :, ; •• ; ■-; i.. ■ , '’.'^ V'r''“!''' ' ,',‘i"’' hi'i ' ^ ‘ " A . •- '■ •■'*♦ Hi’' ., V _.' ' 1 »^ . e^ ' 0 lf . it m *'i' •'- 07 1< ; 1 '. .^||i»yfjl|ilt>*, 774^70 (fct' -« ^ ^ * “' ' ■' *- v-. * '7 •' ' -"■'t» '•i^lXii jWKw'vt t. ‘■' . uri : fh vi '‘hi tv»' 4 Ois^PH -*■ '■ /iV\vp <’■ i» " ‘ 7 'p'tp ’ #i:'*^- . -k^'! fcf f ■*’'* *** ' ' ' ,■ T. '■ • .WStf •'"■? '. ■ ,xi m. „ ■ V i '',ni%^,* -'VJ ' ' ■■•;■• •,Wl , ; ' J|» . , ',.*' ^* V .itfiifSRiC* • ■ i.' ■ -■ . '• ''Is. .' '-lH .1 I *. _. I • * \ ■ Vy> * ^1 tfMiwrff TiWTy j*^*J J( '■ if-^;/'. ■’;?, . \i*. ^ . ./•■? ^Mi' • ; 4- to -fj "'^1^ ffi: ;.c . :'^;~ 50 ment . 6. High terapereture of milk at the receiving platform in the city. 7- Excessive bacterial content of the milk sampled at the receiving platform. " Not until some measures toward enforcement are taken can we expect to obtain milk which has been properly pasteurized and cared for. Pasteurization is a very safe and sane process. 7?hen it is properly carried out much disease due to milk will be eliminated. Pasteurization of milk does not free it from reinfection such as some people seem to think it does. Care should be taken of it to keep it in clean places and well refrigerated. Pasteurization v^en properly carried out can eliminate disease due to milk and insure the safety of its users. -A- ■ a> DwiVv'f .■*•;«. \irJijm HI ' *.i-’’- " \i?V *-■ ■ . ' ' ■ ."S j . '’jll ’ J I Vi"-' ' fSS^ .- ‘ . J.. r>v. '- m ii ... ■’li. ' -'Aift i^W ' ■■ ^ I • ' 7*:' ■ . V"" ' . ■ VI ■’ X y. ■ ' •■ .V ■■ ’*-' ■ . VI ^ ■ ; \: » ,\ Aj, , '- . r.- . &' '-.* ' ^^' '■ 'f ;> ,r<^* .' 4 'yft,^'' ■* ’^'''‘ -w vj: J. ' p*i ,' ^ 1 ■ - ». I ^C*li * 't-.*, »Kt illJif cwf ^fh J5 •* ■'. r‘ ■ ,>' VV..": ■ ’■ ■ >■ •', ' •• ;• ■•«' t '^H /...;•.. ••■.. ■ , ‘ a'- v;;_: ;\v™ rv„ ,'IJ /••*.■-■. A \ S ■ - -^■■-♦w -SZKUIF .'A,. rtf'! T.'’a .w w(f ,-rfwoj Ti* vf*T«rV3(V? rHja^ic* ' ■ ''■ ■• V v-.‘/» .'Vm '■■ , ,v#W ' t. 'j, '. i 5 vi 0 ,-'. ,/. C , * ' « if . i'V if s ■ j ?7 ^ i* - 7 V.'^‘.,'-A • ■■■., >.' f Ij •% ' i a', »*■ 'V-V w l' *1 ’'^Ir . 'U**.,,. '. 7‘ ‘}r '}'^i ^ v/ >ASBii * . • A <..i * f',V**f •■ ’.. •.’■ ■ • .. ‘ ' 7> ' :. .i' . ' .■*V 5 \'>i 1 WiIL' ■ ' .•r.: 'i ' ■:-’'.?,'x,.ii:-.l';-5^-^’... ’ A » '\i»i^;ia0»w ^'- ".< / v' ■■ ■ . . ■ J**’’ ;"v'< Av ';,* ^.' .'•’ 'V ' ' " '“■» i't *r'*V ' ' p ’r's^yr. ■Vji/ :■■ ^ ^ :: ■':^ - '7 '--'vY Bibliography. 1 ?PBteur,L.; Pasteur’s Studies on Fermentations. Page I9 (^879)* 2 Koplik, Henry M.D.; The Sterilization of Milk and the Status of Our Knowledge Upon This Subject. Journal of the Am. Med. Assoc. Yol. 17, pp. (1891). 5 Rogers, Lore A.; Bacteria of Pasteurized and Unpe steurized Milk Under Laboratory Conditions. U. S. Dept, of Agr. Bureau of A.nimal Industry Bui. No. 75 (1905) h Ayers, S.H. and Johnson, Wm.T. ; Bacteriology of Commercially Pasteurized and Raw Market Milk. U.S. Dept, of Agr. Bureau of An. Industry Bui. 126 (I9I0). 5 Tonney, Frederick 0. M.D. ; Organization and Control of Pasteurization. Am. Journal Public Health Assoc. Vol. 10 ( I92O) pp. 716-725. Pasteur, L. ; Studies on Fermentation (English Translation) (1879). 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Public Health Assoc, pp. 664-668 V0I.I (I9 II). Morse, John Lovett M.D. ; Sterilization, Boiling and Pasteurization of Milk. Journal of Am. Med. Assoc. Vol. 60 page 875 (I9l5)» Rupp, Philip M.D. Ph.D.j Chemical Changes Produced in Cows' Milk by Pasteurization. U.S. Dept, of Agr. Bui. 166 Bureau of An. Industry (1915)» ■If t r '■* f . . p vftf’ •* ' ' ' .» ' '•■ . •‘^ ('• ,:• ,• J4? -iP-'iilP •’■''-/•■ ■:^‘lip' 'I " -• ^'v< .v's^/ieJ'.*-3i4i'fj»'f^ ;jU-..rf!) ,:oiy:«^w£rt0’ :^o ■-'y- •' .. "' M, - „ y-'" v' ■ft' >tXp ,A‘,a ^f.j,3 .V* .*#»' ;q. ■ V’j| W' • . • I **iZ- »■■ — r^n’.. ' ■ ■ ■' ^ %'-?r-,rf<^ \o. • '*' ' 'f' V'.'I- ‘ } " ' '4i;>t#-. T t*-' .^ 7i'»;'.'C: v^.O^S ’ ■•\ •-'. , ^ >*^ - TT^je^--, •. ■'••• '■ V . j;;'' * ««'o0‘-i»4 , 'i:^x^)psf (, ^ V S •? ,. i^nu^ ‘^?*- M ' mar .x’7‘ ^ ■X Q , 0 lay , , _.. ^ “ — ‘“f yj sfa si 'T iyj ' tf Tg wg * uyw t ai' W ;;^ '■ n Kershaw, John B.C.; Milk Sterilization by Electricity (Lethal Tube /pperatus Destroys Disease-Producing and Milk Souring Bacteria in Raw Product). Engineering Magazine Vol. Ay pp. 9 ^^-9 ^9 (^9^ A) The Use of Electricity in the Continuous Sterilization of Milk.(Agr. Caz. N.S. 17ales, SA (I9I5). No. 12 pp. IO79-IO8O) Exp. Sta. Records Vol. 50 PP* 7?^ (191‘^-^)* Freund, T.; Lobeck’s Biorisator Process. (Molk. Ztg. 'Hildesheim), 27 (I9I5) No. 77 pp. 1 A69-1 A9 1 j abs. in Internet. Inst. Agr.(Rome), Mo. Bui. Agr. Intel, and Plant Diseases A(1915), No. 12, pp. 1919, 1920). Houghton, E.M. (M.D.)^nd Davis, Lewis; A Study of the Germicidal Action of the Ultraviolet Rays. Journal of the Am. Public Health Assoc. Vol. A pp.22^“2A0 (I9 IA). Fouassier, M.M. ; The Microorganisms Persisting in Milk After Pasteuriaation! Their Role in the Decomposition of Hydrogen Peroxide. Compt. Rendu I7I; No. 5 527. (I92I).